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W R

D E P R T M E N T T E C H N I C L

M N U L

ORDNANCE

MAINTENANCE

105-MM HOWITZERS

M 2 AND M2A1;

CARRIAGES

M2A1

AND

M2A2;

AND C O M B A T VEHICLE

MOUNTS

M3

A N D

M4

DEPARTMENT •

SEPTEMBER 944

8/19/2019 TM9-1325 105mm Howitzer

2/219

W

 R DEP

  RTME

NT

TECH

NIC L

M NU

L

TM

 9 132

5

This Te

chnical 

M

anual s

upersedes

TM 9-1325, da

ted

28

No

vember 19

42, a

nd Changes

 No.

1,

dated

30 August 1943.

This Technical Manual

also 

supersedes TB 

ORD 49,

dated

6

May

1943;

 

T

B ORD 

110,

date

d

22 une 1

944; and

TB

 ORD

138,

dat

ed

10

Au

gust 194

4

ins

ofar as they

app

ly to

TM  9-1325.

  TB  ORD

49, TB

 

O

RD

110, and TB  ORD

138 remain

  i

n

force until

s

uch time as

they are  incor

porated

in other affec

ted manuals

or sp

ecifically

resc

inded.

O

RDN

NCE M  IN

TEN

NCE

105-MM 

HO

WI

TZE

RS

M2

  A

ND 

M2A

1;

CA

RRIA

GE

S M

2A1

  AND

  M

2A

2;

A

ND

 

C

OM

BAT

  VEH

ICL

E

MO

UN

TS

M

3 AND

 M

4

W

R DEP

 RTME

NT

•

2 SEPTE

MBER

1944

DISSEM

IN TION

O F RES

TRICTED

 

M

  TTER

[ he information contained

in

restricted

documents

and 

the

essential char 

acter

istics 

of restr

icted materia

l

m

ay

b

e giv

en to any person

 

kn

own

to

b

e

in 

the

se

rvice of

the Un

ited

Sta

tes a

nd to persons

 

o

f un

doubted loya

lty and 

discretion

 who ar

e co

operating

in Governme

nt work, but w

ill

n

ot be com

 

municat

ed to

t

he p

ublic

o

r

to the press except

by

authori

zed

mi

litary pub

lic

rela

tions

agenci

es. See

 

a

lso  paragra

ph

23i,

AR

  38

0-5, 15 Mar

ch 1944.)

8/19/2019 TM9-1325 105mm Howitzer

3/219

WAR DEPARTMENT

Washington 25, D. C, 21 September

1944

TM

9-1325,

Ordnance

Maintenance:

105-mm

Howitzers

M 2

and

M2A1; Carriages

M2A1

and M2A2; and Combat Vehicle

Mounts M3

and M4, is published for the

information and

guidance

of all

con

cerned.

1-A.G.

  O O

300.7 (23 May 44)

300.7/994

BY

ORDER OF

THE SECRETARY

OF

WAR:

G. C. MARSHALL,

Chief of

Staff.

OFFICIAL:

J.

A. ULIO,

Major

General,

»

The Adjutant

General.

 

DISTRIBUTION: A s

prescribed in

Par

9a,

FM 21-6; IBn

9 (2);

1C

9

(3);

Ord Decentralized Sub-O

(3);

P/E

(Mark

for

Ord

O)

(5);

H

R

Points (5);

Ord Dist

O

(5); Ord

Regional

O

(3); Ord Dist Br

O

(3); Ord Establish

ments (5);,Ord

Tk

Dep (3).

IBn

9—T/O 9-15; 9-75; 9-315;

T/O

E

9-65.

1C

9—T/O

9-17;

T/O &

E

9-7;

9-9;

9-57; 9-67;

9-316;

Hq Sv

Co,

Ord Base Auto Maint

Bn; 9-318;

9-377.

(For

explanation

of

symbols,

see FM 21-6.)

8/19/2019 TM9-1325 105mm Howitzer

4/219

CO

NTENTS

  Paragraph* Pages

S E C T I O N I.

Introduction .................................. 1- 4

1- 15

II. I

nspection

...

................................... 5-25

15- 39

III. Mai

ntenance, general ...

.................

26-27 39-42

IV. Ho

witzer

..

......................................

28-30 42- 5 1

V. Recoil mechanism

31-33 51- 62

VI. Equilibrator .........................

......... 34-37

62-

74

VII. Shields and bra

ckets 38-42 74- 81

VIII.

Firing

mechanism

43-46

81-86

I

Elevating

mechanism .......'............. 47—

53 86— 1 1 4

X.

Crad

le and elevating arcs

.............. 54-59 115-136

XI.

Traversing mechanism ........

.......'... 60-64 136-148

XII. Top

carriag

e and pintle p

in 65-66 149-154

XIII.

Whee

ls, hubs, tires, and brakes 67-71 154-1

68

XIV. Trails .............................

............... 72-76 168-186

XV. Axle and equal

izing support 77-83

 

186

-208

XVI. Lubrication ..........................

..........  84 208-209

XVII. References ....................................

85-87 209-211

I N D E X

'...........................

........................................................

212-214

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O

 

O

V

E

R

 

M

5

D

M

E

 

O

V

E

R

 

D

R

P

8

F

g

e

 

0

m

m

 

H

w

f

e

M

A

a

C

a

M

A

W

h

C

s

n

a

e

 

K

U

r

n

i

>

>

g  

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6/219

TM  

9 1325

 

1 2

This Technical Manual superse

des T

M

9-1325

 

dated

2

8

Novemb

er 1942 and

Ch

anges No. 1

dated

  3

0

August 19

43. This Technical Manual also

supersedes 

TB

O

RD 49 dated

6

May 1943;

TB ORD 110 dated

22 June 1944; and

TB ORD 138 dated

10

Aug

ust 1944 insofar

as they

apply to

TM 9-1325.

TB

ORD 49

TB

O

RD 110

and TB ORD 138 remai

n in force

until

such time as they are incorporated

in other affected man

uals or specifically rescin

ded.

  ection

INTRODUCTIO

N

1 SCOP

E

a.

This manual

is-published

for

the

information and guidance

of

ordnance

maintenance

personnel.

 

It contains

detailed

instructions for

in

spection,

disass

embly,

assembly,

ma

intenance, and

 repair

 

of

the

 

105-

m

m Howitzers M2 and M2A

1, Recoil M

ecnanism M2A1, an

d 105-mm  

Howitzer

Carriages

 

M

2A1 and M2A2,

supplement

ary to

instruct

ions

in 

TM

9-325.

This manual

does not contain

informati

on on operation,

adjus

tment,

an

d maintena

nce

n

ormally performed

  by

the using

 

arm,

since

such

informa

tion is

available to ordnance

maintenance

person

n

el in TM 9-325.

2 CHARACT

ERISTICS

a

Howitzer. T

he

1

05-mm Howitzer

M

2A1 

may b

e

employ

ed

for 

direct

or

indire

ct fire.

It may be

used with

effect

aga

inst nearly 

all ty

pes

of

targets.

The howitzer uses 

semifixed

am

munition of

sev

eral classi

fications: H E ; H.E.,

A.T.; Sm

oke,

B.E.;

H-Gas; and Smo

ke

(bursting char

ge). The weight of

the high-explo

sive

projectil

e

is

 33

pou

nds,

and

the maximum

 

range

with 

the high-explosive ammuniti

on

is

12,205

yards.

b 

Carriage.

The

105-mm

 Howitz

er

Car

riages M2A1 a

nd M2

A2

are

field car

riages

of

the

single-axle, split-trail t

ype. In additio

n to

having all

the

features of

a 

howitzer

car

riage,

the carriages are use

d

for

lo

w angl

e (long

range) firing.

The carriages

m

ay be tow

ed

at

spee

ds

up

t

o

35

miles per

hour. They may be

maneuvered

rapidly

i

n

and out

of

firing p

osition. 

An

equalizi

ng mechan

ism

faci

litates firi

ng

from

unev

en terrain.

c.

In  direct

laying,

a 

one-man, one-sight 

system

may 

be

used, 

wherein the gu

nner

la

ys

the

 

piece

both

for direction and

elevation,

using

the

pano

ramic

telescope located

on

the

left s

ide

of

the

 

carriage.

When a more

rapid ra

te

of

fire

is

de

sired, the two-man,

 

two-sig

ht

system

is used.

In

this case,

the gunne

r lays for

 

dir

ection

only,

an

d

the

nu

mber cannoneer

lays

for ele

vation, employi

ng

the

elbow

telescop

e at

tached

to

the

right

side

o

f the

 

carriag

e.

 

8/19/2019 TM9-1325 105mm Howitzer

7/219

^

^

K

 

T

H

K

 

C

D

W

B

M

1

A

M

B

D

3

 

S

G

H

R

L

A

M

B

 

i

t

p 

J

K

J

 

T

R

A

L

R

G

H

R

 

P

D

 

8

F

i

g

u

r

e

 

m

H

w

z

M

A

a

C

a

M

A

 

g

 

i

 

8/19/2019 TM9-1325 105mm Howitzer

8/219

T

M

I

N

T

R

O

D

U

C

T

I

O

N

9

 

1

3

2

5

 

2

 

0

0

 

O

 

O

)

 

a

 

O

)

8/19/2019 TM9-1325 105mm Howitzer

9/219

8/19/2019 TM9-1325 105mm Howitzer

10/219

T

M 9 1325

 

2

I

NTRODUCTION

SHIELD.

UPPER  

LEFT Cl

45537

FLAP

TOP

LEFT B292127

SHIELD 

UPPER

RIGHT C145536

FLAP TOP

RIGHT 6292

126

BRACKET

/C93046

SHAFT 61576

47

PIECE

-

A17

2496

RA PD

83584

Figure 5

105

 mm Howitzer

M

2A1

and Carriage

M2A

2 Rear

 

View

 

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11/219

TM

9

 1325

 

ORDN

A NCE

 

M

A INTE

NANC

E- 

105-

MM HOWITZ

ERS

M

2 

A N

D  

M2A1;

 

CARR I

AGES M

2A1 A ND

  M2A

2; A N D

COM

B A T VE

H ICLE

 

M

OUNT

S

M3 A ND

  M4

IN  

I

N

t

 

o o

^  9

 

_£

ftV

 

£

sv

 

.

 

_

  •< L

U L

U I LJ

LUL

U

— i i

— t/1

 

?n

 

in

o

o

CO

 

O

 

o

u

O

8/19/2019 TM9-1325 105mm Howitzer

12/219

TM

  9 

13

25

INT

RO

DU

CTI

ON

l t

•

o

4

N

 «

t

t

 

8/19/2019 TM9-1325 105mm Howitzer

13/219

T

M

9

 13

25

O

RDN

A NC

E MA

IN TE

NA N

CE  

05

 MM

  HO

W IT

ZER

S

M2

 

A ND

 

M2A

1; 

C

A RR

IA G

ES

M2

A 1 A ND

 

M2

A2 ; A

ND   CO

MB A

T

VEH

IC L E

 MO

UNT

S

M3 A ND

 

M4

00

8/19/2019 TM9-1325 105mm Howitzer

14/219

T

M

 

9 

1

32

5

RA

  P

D

45

84

2

F

igu

re

 

H

o

wi

tz

er

 I

ns

ta

lle

d

 in

 

M

ot

or

 

C

a

rr

iag

e

 

M

7

Re

a

r Vi

ew

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15/219

TM 9-1325

O R D N A N C E MAI NT ENANCE

05-MM HO W IT Z ERS

M2 A N D M2A1 ;

C A R R I A G E S

M2A1

A N D

M2A2 ;

A N D

COMBAT V E H I C L E

MOUNTS

M3

A N D

M4

R A PD 322345

Figure 70

— Howitzer

Installed in Motor

Carriage

M7B1 Rear

View

10

8/19/2019 TM9-1325 105mm Howitzer

16/219

TM 9-1325

3

IN TRO D U C T I O

N

3

DIFFEREN

CES

AMONG

  M O

DELS.

a.

Howitzert .

The 

only

d

ifference between the

Howitzer M2A1

and the Howitzer

M2

is 

that

the

M2A1 model

has two bearing strips

on

t

he bottom

  of

the

 

breech ring  which

are not present on the

M2

mode

l.

h.

Recoil

Mechani

sms

The

chief

difference betwe

en Recoil

Mechan

ism

M2A

1 and

Recoil Mechan

ism

M

2 is the respirator

pro 

vided at 

the

rear

end of

the

M2A1

Recoil Cylinder. The

M2 model

is bein

g ch

anged

to

M2A1  by

MWO

OR

D  C21

-W10

or

  (FSMWO

C21-W10)

.

The

Recoil

Mechanism  M2 is not

 cov

ered

in this

manual.

c

Carriages

(1) The

C

arriage

M

2A2 differs from

 

the

other

m

odels

mofet

notably in

havi

ng two

shields

, a

main

sh

ield and

an

au

xiliary shield

(figs. 1

2

, 3,

4,

and

5). New M2A2

Carriag

es

ha

ve

the

screw-type

traversing

mechanism.

However,

M2A2 C

arriages which have been

mo

dified

from

 M2A1 or

M2 Carriages

have a worm and r

ack

traver

s

ing mechan

ism. Hand

parking brakes, only,

are p

rovided. New

hand

 

parking brakes

are equipped

with clasp-

type

brake

levers.

(2)

  The

Carriage M2A1

has

the 

old type of

shield and a

worm

and

  rack

 

trav

ersing

mechanism (

fig. 6).

Hand

  parking bra

kes, only,

are prov

ided.

(3)

M2

Carriages

have

electric

br

akes,

o

perated fro

m  the

prime

mov

er, as well as ha

nd

park

ing

brakes. M2 Car

riages

are

bein

g

con

verted 

to

M2A1

Carriage

s

by the

removal of the elec

tric brakes. This

m

odification is

being made by

MWO

O

RD C21-W

9. The  M

2

Car

riage

is

no

t described in

 

this ma

nual.

d.

Mounts The

105-mm Ho

witzer

Moun

t

M3 (fig. 7),

t

ogether

with Howitzer M2A1, is

mounted in the

Motor C

arriage T .19. The

105-

mm

Ho

witzer Mount

M4, together

w

ith 

Howit

zer

M2A

1, is

mounted in the 

Motor

Carri

age 

M

7

or

M7B1 (

figs.

8, 9, a

nd 10).

Some of the

differences

between

the

mount

s

and

ca

rriages are noted

below.

(1)

The e

levating

arcs

for

the mounts ha

ve been

cut

t

o

allow for

only

 

30 degrees

45

minutes 

elevation, 

the

equalizing support and 

axle have

been shorten

ed,

the

axle is sec

ured to

th

e  chass

is

of the

vehicle,

  and different shie

lds are used.

(2)

Sighting and

fire con

trol

instruments

used

with

Mou

nts M3

•and

M4 are

different  from

those used

with Carriages M2A1 an

d

M2A2.

11

8/19/2019 TM9-1325 105mm Howitzer

17/219

TM 9 1325

ORDNANCE MAINTENANCE 05

-MM HOWITZERS  M2

AND

M2 A 1 ;

C A R R I A G E S

M2A1 AND M 2 A 2 ;

AND COMBAT

V EH

ICLE M

OUNTS   M 3

AND

M 4

4. DATA.

a.

Howitzer 105-mm.

M O D E L

M 2 A

1

Caliber of

 

howitzer

10

5-mm (4.134

in.)

Total weight of

howitzer (tube and breech mechanism)

(approx) ................................

.......................................... 1,064' Ib

Weight

 

of

 

tube

(approx) .................................

....................... 7Q6 Ib

Weight of tube

and

b

reech ring

(approx) ..............................

973-

Ib

Weight 

of

tipping

parts

(howitzer,

recoil

mechanism, cradle,

sight mount, and range

quadrant)

(ap

prox) ..

..............

2,028 Ib

Length of

how

itzer (muzzle to rear face

of breech ring).... 101.35

in .

L

ength

of tube

............................................

..........................

93

.05 in .

Length of

bore ...........................................

..................:...... 78.02 in .

Muzzle

velocity

(averag

e^ velocity with a new h

owitzer)

Shell, H.E.

  (maximum  zone charge, Carriage M

2 or

Motor Carriage

M7

............

........................

1,550

ft

per

sec

Shell,

H.E.,

A.T.

(Carria

ge M2 o

r

Motor Carriage

M7) ............. 

1,250 ft

per

sec

R

ange (

maximum):

Shell, H.E. (maximum

zone charge at 778.6 mils,

Car

riage M2)

 

....................

............................................ 12,205 y

d

Shell, H.E., A.T. (154.6

mils,

C

arriage M2)....................

3,500 yd

Shell, H

.E., A.T. (

778

.1 mils,

Carriage

M

2 ) ................... 8,590 yd

Sh

ell,

H.E.,

 A.T. (152.5 mils, Motor Carriage

M7)........ 3,500 yd

Rate

of fire:

Normal .........

....................................................... 2 rounds

per

min

M

aximum

..

........................................................

.. 4 rounds

per

 min

Type of breechblock .. .

..... ...............

..

........ Horizontal

sliding wedge

Weight

of

breechblock

(approx)

................................................

74

Ib

Type

of

firing mechanism

Co

ntinuous

pull

b

. Carriage

Howitzer

105-mm.

Mode

l

M 2 A 1

M2A2

Time to emplace

(normal) ............

..:........................... 3 min 3 min

12

8/19/2019 TM9-1325 105mm Howitzer

18/219

TM

9 132

5

INT

RODUCTION

Model

M2A1

M2A2

W

eights:

Howitze

r

a

nd carriage

complet

e

wi

th ac

cessories,

traveling

position) 

(approx)

 

.....

...................

...................

. 4,475

Ib

4,980 I

b

Wheel 

with

combat tire (9

.00 x

20)

(appro

x) ............

...............

........

287  Ib

287

Ib

Wheel

with

combat tire

 

and

hub

(

approx) ............

.:.................

......,......

345

Ib 34

5 Ib

At lunette (a

pprox) ......

....................

.... 235

Ib  

235 Ib

Dimensions

in

traveling

position,

over-all:

Length

(approx)

 

.

...................

..............

19 ft

19

  ft

Width

(over hub c

aps) (appro

x) .......

. 84 V z

in.

  8

4Vz

in.

Height (approx

) .................

.................

60 in.

62

in.

Road

clearance

 

(ap

prox) .

...................

.... ISVa in.

13

in .

Turning

 

radius

(approx)

.........

...............  l

ift

11'ft

Towe

d  by prim

e

move

r:

2*/2

ton ...........

...................

........ 6

x

 

6

cargo

truck

6x6 cargo truc

k

13 ton 

..................

.......... H

igh speed

trac

tor

MS

 

Hi

gh sp

eed trac

tor 

MS

Lim

its of elev

ation:

M

aximum (a

pprox)

1,180

mil

s

1,1

80

mils

Depre

ssion

(approx)

................

........ -84

 mils

-84 mils

Elevatio

n per turn o

f handwhee

l ..........

10 mils 1

0

mils

Li

mits of

  traverse (degrees

 righ

t or

lef

t

(appr

ox)) ..........

...................

............ 23

'deg

23 deg

Diam

eter of

 

c

ircle of

 

emp

lacement

(approx)

............................................

21.1ft 21.1ft

Traver

se

p

er turn

of handw

heel (screw-

 

type

traversin

g

mech

anism) .

......... 19

mils

  19 m

ils

Traverse per

turn

of handwhe

el

(

worm

and

 rack tra

versing

m

echanism)

21 mils

21

mi

ls

M2AJ and

M2A2

Recoil m

echanism:

Mod

el

..

....................

......

e

..

...................

.......

?

&/*.-«*

Norma

l leng

th of recoil

lgf.630 

inches  ............

42

in .

\ |f.x»>

Maximum

allowable recoil

'

inches ..........

.. 44 in .

Eleva

tion at which maximu

m r

ecoil occurs m

axi

mum

eleva

tion) ...................

........;..........

........

1

,180

m

ils

Type .............

...................

...................

..................

.

H

ydropneum

atic

Weight

(com

plete with

sleigh and

 filled)

—

pound

s (approx) .........

...................

..................

463

Initi

al

gas p

ressure at

70° F, w/o reserve

 o

il .... 1,1

00

I

b

per 

s

q

in.

13

8/19/2019 TM9-1325 105mm Howitzer

19/219

T

M

9

 1325

4

O R D N A N C E M

AINTENANCE 05-MM

H O W I T Z E R S

M2 A N D M2A1 ;

C A R R I A G E S

  M2A1

AND M2A2 ; A N D C O M B A T  V E H I C L E

MOUNTS M3 AND

M 4

M 2 A1 a n d

M 2 A 2

Recoil

oil:

T

ype

................................

..................................

See

par.

33

Reserve in

recuperator (fills

of oil

screw

(filler) gun)

.................

.................................

1

V

Type  of

equilibrator

..............................

................

Spring

Tires:

Type and size

...............

.....................................

9.00 x 20 combat

Type

and

size tubes ............

.............................. 9.00 x 20 combat

Type

and

size

......................................

(8-ply)

7.50

x

24

standard

Type and

size tubes ..............

............................ 7.50 x 24 standard

P

ressure (combat

or

 standard) ........................ 40

Ib per sq in.

Brakes,

type

.....

.......................................................

.. Hand

parking

c. Oil-carriage

Sigh

ting Equipm

ent.

Range

Q

uadrant M4.

T

elescope Mount M21A1 with

Panoramic Telescope

M12A2 or

M5A3.

Teles

cope Mou

nt

M23

with Elbow

Telescop

e Ml6.

d. Off-car

riage 

Sig

hting

and

Fi

re Control Equipment.

Aiming

circle Ml or M1918.

Aiming

 post

Ml.

Aiming post light M14.

B.C.  te

lescope

M19

15A1.

B.C.

telescope M65.

Binoculars.

Compass

M2.

Compass

 (prismatic) M1918.

Firing table 105-H-3.

Firing table (graphi

cal)

M4.

Fuze

 

setter M14.

Fuze

setter

M22.

Gu

nner's quadrant Ml or M1918.

Range finder (1

meter base)

M

1916.

Range

finder

M7.

Testing target C76012.

Watch.

e. Subcaliber

Equipment Gun Subcaliber 37-mm

M13.

We

ight of

gun

..................................

............................................

86

Ib

Length of

gun

.......................

...................................................

33.4 in.

Length of

bore

.................................................

....................... 29

.11

in.

14

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20/219

TM

9-1325

4-5

I N S P E C T I O N

Range:

SHELL,

practice, M63—Mod.

1 , w/FUZE, base,

practice,

M58 ................................................................................

4,980yd

SHELL, practice, M92, w/FUZE, P.D., M74

..................

5,165 yd

Muzzle

velocity:

SHELL, practice,

M63—Mod.

1 , w/FUZE, base,

practice,

M58 ...................................................................... 1,100

ft

per sec

SHELL,

practice,

M92,

w/FUZE,

P.D., M74 .... 1,276

ft per

sec

Se c t i o n

II

INSPECTION

5.

PURPOSE.

a.

Inspection of the weapon is vital. Thorough, systematic

in

spection

is

the best insurance against an unexpected breakdown at

a

critical moment when

maximum

performance is absolutely necessary.

Never let materiel run

down

Keep

it

in

first class fighting

condition

by

vigilant

inspection.

b. The immediate aims of

inspection

are:

(1) To

determine

by critical examination the

condition

of the

materiel.

(2) To detect faulty or careless

preventive

maintenance, espec

ially

inadequate

lubrication.

(3)

To determine

whether

adjustments, repair, or replacement of

parts is necessary.

(4)

To

verify

that

all modifications

authorized

by

Modification

Work Orders have been made.

c.

Inspection should always be accompanied

by corrective

meas

ures

to remedy

any deficiencies or defects found. When properly car

ried

out,

inspection and necessary corrective maintenance will

insure

the

maximum performance of

the materiel.

d.

The results of inspection should be noted in the

Artillery

Gun

Book (O.O.

Form

5825). Any unusual condition which

might

result

in

improper

operation, damage

to

materiel,

or

injury to

personnel,

will

be remedied

immediately.

e.

Suggested improvements in design, maintenance, safety, and

efficiency of

operation

prompted

by

chronic failure or malfunction of

the

weapon,

spare parts, or

equipment

should be forwarded to the

Office of the Chief of Ordnance, Field Service Division, Maintenance

Branch,

with all

available

pertinent information. Such suggestions

are encouraged in order that other organizations may benefit.

15

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TM 9 1325

O R D

N A N C E

MAINTENA

NCE 05-MM H O W I T Z E R S

M2 AND M 2 A 1;

C A R R I A G E S

M2A1 AND

 

M2A2;

AND

C

O M B A T

V E H I C L E

MOUNTS M3

AND M4

 

Figure

— Tools

for Inspection

and Maintenance

of Recoil Mechanism

16

RA PD 22576

8/19/2019 TM9-1325 105mm Howitzer

22/219

CAUT

ION:

th

orized 

6.

TM 9 1325

 

5 6

INSPECTION

No

modific

ation of materiel will

foe made unless a

u-

T

OOLS FOR INS

PECTION

a. Tools

for ordnan

ce m

aintenance of the 

105-

mm howitze

r

m

a

teriel are listed

in

SN

L C-18. N

o special tools ar

e

issued

t'o o

rdnance

mainte

nance personnel for inspection o

f the howitzer

and carriage.

Special

tools

are 

issued for insp

ection of the

 recoil mechanism

, and

those tools are

illustrated in figure

 

11 

and

described

below

.

b

Tool

s for Inspectio

n  of

  Recoil

Mech

anism

Use

oo ls

GAGE

, pressure,

w/connec

tion, 45-G-290

  (

fig. 11).

JA

CK, retractin

g, 41-J-159-

160

(fig.

11).

PLUG,

fi lling,

(fig. 1

1).

45-P-1490

Used for

testing gas pressure in

 

re

cuperator cylinder.

This gage

is

calibrat

ed

from 

zero

to 2,844

pounds

per square inch.

Used

to

retract

the howitzer

when

perform

ing the m

anometer

test

(par. 11).

This

is

a

spare

recoil

cylinder

plug

for use wit

h press

ure

gage conn

ec

t

ion B17128.

Used to

  measure the temperature 

of

the

  recoil oil

 

when 

perfo

rming

the

manom

eter

test. T

he ther

mometer

is

calibra

ted

from

minus

10° F to plus 22

0° F.

Used

to

remo

ve recoil cyli

nder 

r

espir

ator

in

mano

meter

test

and

 

in

maintenance of recoil mech

anism.

WR

ENCH, piston  r

od wiper

followe

r, 41-W-3248-525

 

(fig.

11).

WRE

NCH, recoil 

s

tuffing

bo

x

head, 41-W-3248-

553

(fig. 11).

c Tools

fo

r Che

cking Pressure G

age

U

sed

in

Manometer

Test

(1) The

contents of the

pressure

gage

  tester chest

(fig. 12) are

used

 

wh

en checkin

g

the 

service pr

essure 

g

age again

st a m

aster gage.

The pressure

 

gage teste

r is

 

filled

with recoil

oil

which

is

subjected to 

pressur

e by a screw. The

pressure is transmitted

equally

to

both pres

sure gage

s, thereby

s

howing

wheth

er the

service 

pressure g

age is

readin

g

p

roperly.

T

HERMOMETE

R,

Fahren

 

heit,

18-T-1321

(fig. 11).

W

RENCH, respirator, 41-

W-1999-300 (fig.

11).

Face-spanne

r-type wrench u

sed to ad

just

piston rod wiper follow

er.

Face-spanner-

type wrench us

ed to ad

just rec

oil

stuffi

ng box head.

17

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TM 9-1325

O R

D N N C E

M AIN

T EN AN CE-105-MM

HOW I T ZERS M 2 A N D

M 2A1;

C R R I G E S M2A1 AND M2A2; A

ND  C

OMBA T V E H I C L E

MOUNTS

M 3

A

ND M 4

(2)

The following

equipmen

t

is

provided:

T o o l

*

ADAPTER, pressure ga

ge

tester, 4>A-199-501 (fig.

12) .

ADAPTER, pressure

gage

tester,

45-A-199-500 (fig.

12).

U ie

Used to connec

t

pressure

gage to

tester.

Issued w

ith

all outfits bu

t not used

with master ga

ge

45 -

G-288.

This

adapter

is

used only with 1 5 5

-mm

and 240-mm howitzer

 

m

ateriel.

GAGE,

pressure, hydraulic,

0 Kg.

-200

Kg., master,

45-G

-288 (fig. 12).

Used

to

check  accuracy of

service

pressure gage. I

t

is gradua

ted

from

zero to 2,844 pounds per square

inch. The

ga

ge should be re

turned

to

an arse

nal once a year

for verifi

cation

of its accuracy. Care must

be

exercised 

not to

jar

instrument

at any time.  This

gage

is never

used

 to

perform

a

manometer test.

GASKE

T,

oil

re servoir, 33-G-99

9-30;

GA

SKET, suction piston, 3

3-G-999-

2

0;

GASKET, adapter, 33-

G-999-10; and

GLA SS, gage, 45-G-1903-50 a

re

spare

parts.

Used to remove service pressure

gage

indicator hand

 when service

gage

is

not

in

agreement

with

master

gage.

Used

to place 

serv

ice

gage indicator

hand in

agreement

with master.

gage.

(3) USE O F P RESSURE

GAGE 

T E S T

ER. Clamp

tester

securely

 in

the

vise by

means

of the lug on

the under side. Withdraw

the

screw

and fill th

e

a

pparatus

with recoil o

il before assembling the pressure

gage

in order

to eliminate possible

 

air

bubbles in the

connecti

ons.

S crew

the

master

gage

in to

one

arm

of

the tester

and

the

gage

to be

tested

 into the other arm, us

ing the adapters 45-A-199-50

1 (fig.

13).

Apply

pressure by

mean

s

of the

operating

screw and handle, and

compare readings over the

entire

range

of

the

ga

ges.

If

the gages

are not

in agreement, pull the

hand

o

ff

t

he service pressure

gage

sp indle, using the

gage

h

and jack  (fig. 14), and

reset the hand in

agreement with the master gage. Use a

small hammer and the

gage

hand set

when resetting the hand (fig. 15). Tap

ve

ry 

lightly. The

18

GASKETS and

GLASSES

(fig. 12).

JAC

K, gage hand 41-J-105

 

(fig. 12).

SET,

gage hand 4 1 -S-213 5

(fig. 12).

8/19/2019 TM9-1325 105mm Howitzer

24/219

IN

S

PE

C

TI

ON

T

M

9

 1

3

2

5 

6

 

2

O

O

£

19

8/19/2019 TM9-1325 105mm Howitzer

25/219

T M 9 1325

6 7

O R D N N C E MAINTENANCE- 105-MM 

HOW

ITZERS

M 2

AND

M2A1;

C R R I G E S M2A1 AND M2A2; AND

CO M BAT

V E H I C L E

MOUNTS M 3 AND M 4

 

RA

PD 87856

Fig u

re Service

 

Pressu

re

Gage

most

effective

rea

dings are between

430

and

2,300 pounds per square

inch.

7. BO

RE.

a. General

The bore should be free

from

dirt,

grit, rust, and

powder

fouling.

Do not confuse powder fouling with coppering

of

the

bore. A

clean bore 

is not necessarily

a

shiny bore

and

migh

t

fre

quently

h

ave

a

dull g

ray appearance. A

  shiny,

polished

bore may

indicate

 

that abrasives

have been

used in cleaning

oper

ations.

b

Damage to Forcing Co

ne Scratches,

nicks,

pi

tting, and s

cor

ing of the bore

may permit

leaka

ge of gas

past

the rotating

band of

the projectile w

hich will cause erosion of the b

ore, loss of velocity,

and conse

quently loss of

range. Such

defects

must be smoothed and

rounded

and, depending on their

location,

character, and

extent,

deci

sion

must

be

made 

as 

to

whether the 

weapon

is 

serviceable from

the

standpoint of

gas

 leaka

ge. No definite

rules

of thumb on serviceabil

ity of the weapon

can be given.

c

Deformation

of

Rifling

Particu

lar

attention should

be paid 

to deformation

at the origin of rifling. In g

eneral, it consis

ts

of

sheared lands and

a

flo

w of metal in the grooves so that the

 

pitch

of

the r

ifling

for the

first inch or two

is considerably reduced and pres

sures increas

ed.

This

is a serious defect and howitz

ers showing it to

20

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26/219

TM 9-1325

I N S P E C T I O N

R A

P D

87857

Figure

4

Removing

S erv i ce P res s u re

Gage Hand

R A P D

87858

Figure 15 —

R e s e t t i n g S erv i ce P res s u re Gage

Hand

21

8/19/2019 TM9-1325 105mm Howitzer

27/219

T

M 9 132

5

7 9

O R D N N

C E M A

I N T E N A N CE

 

0 5 M M  

H O W I T Z E R S  

M2 A N D

  M2A1;

C R

R I   G E S

M 2

A 1 A N D M2A2; 

A N D C O M B A T

  V E H I C

L E M O U N T

S M 3  A N D M 4

a

marked deg

ree 

are

n

ot to b

e

reissued.

Stripping

  or

gougi

ng of

lands

occurs

especially

at

or

near the

origin 

of rifling.

d 

Pastil

les.

Thes

e

are small dep

ressions occasio

nally  f

ound in

the

howitzer

tube. Th

e effect of

pastilles up

on  the saf

ety  and ac

cu

racy of the pie

ce is thought

 to

 be neglig

ible. How

ever,

as

  a pre

cautio

nary

measure

, tubes having

more than

  three

pastill

es

the size

 

of

a

5-cent piece

 

will

be w

ithdrawn from

service, if

pract

icable.

e.

Star gagin

g. T

he average life of the

  tube

  is   approxim

ately

7,500

roun

ds. Ho

witzers in ser

vice should

be star-gaged a

fter

ap

proximately

90

percent

of 

their estimated accuracy

life,

and there

a

fter at

each

10

percent

during the

remain

der

of

 

th

eir service

. T

ubes 

m

ay be

 star-g

aged

an

y time

an

in

spector finds

it a

dvisable. D

ecop-

perin

g

of

bores of tube

s is

prohib

ited.

Ins

tructions for

star

-gaging

are given

in TM 9-1860.

8.

TUBE A

ND

BREECH R

ING par.

30).

a. Exami

ne the bre

ech

r

ing 

and howitzer tube for

 pro

per

a

ssem

bly

and

tightness. 

The

breech

recess

should be

clean

and

free

from

rust,

pits, burs, sco

res, or

other damage. 

The level

ing plates

 should

be free

from dirt, burs

, scratches

, roughness

, and  p

aint, and  parallel

with

 

th

e axis of

 the bore. 

The

operat

ing lever ca

tch

s

hould

be

tig

ht 

and free 

from

wear

 

or da

mage. Rem

ove 

th

e

screw  from the

recoil

mechanism

 

b

racket

locking ring,

remove

 the locking ring,

and inspect

 

the

 con

dition of l

ocking

ring

th

reads on tube

and in

ring.

  Also  ex

amine

the

conditio

n a

nd tightness

 

of the

recoil me

chanism bracket

seat ring  before

 repl

acing

lock

ing ring

and

scre

w.

9.

BR

EECH MECHA

NISM AN

D

FIR

ING

LOCK

p

ars.

28 and 29).

a. The

bre

echblock  sho

uld open and

 

clos

e wi

thout binding

  and

lock

positiv

ely in

the 

closed

position. A

ll  sliding

surfaces,

threads,

 

etc.,

should

be smooth

and  free fro

m

burs

or scra

tches.

Parts m

ust

be clean a

nd

pro

perly

lu

bricated. Ex

amine

the 

breechbloc

k

bu

shing 

for

 

worn

firi

ng

pin

ho

le and

tight

ness

in

breechb

lock.

Th

e su

rface of

th

e

breec

hblock

b

ushing shou

ld be flush

with

 

the

surface of the

bre

ech

block.

Screw 

should be secure

and

flush 

with or

below surface.

In

spe

ct

the follow

ing spe

cific parts fo

r sa

tisfactory op

eration, scores,

deformatio

n,

cracks

, breakage,

  wear,

or

o

ther da

mage;

breechbl

ock

op

erating  lever

assem

bly, operatin

g lever pivot,

ex

tractor, trigg

er

shaft, trig

ger shaft detent

and t

rigger shaft de

tent spring,

firing lock

,

an

d

f

iring

sprin

g.

Exami

ne

con

dition an

d check

protrusio

n

of firin

g

pin

.

Firing pin must

not be

 broken

 

or

deforme

d and mu

st

have suf

fi  

cient

 

forc

e to

fire

  prim

er.

22

8/19/2019 TM9-1325 105mm Howitzer

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T

M  9 1325

10-11

INSPECTION

10

RECOIL

MECHANISM.

a.

T

he

howitzer should recoil the

 

prescribed

distance smoothly

and

return

to 

battery

completely and

without

shock.

b. Check

that

recoil

slides are clean, free

from

rust, burs,

and

scratches, and

properly lubricated. Note that sleigh

rails fit cradle

guides snugly.

 

S ee

th

at

the threads on the

piston rod and

 

outer nut

 

are

not

burred or

stripped. S ee that the piston rod

outer

nut

is

secured

by

a cotter pin. E

xamine

fi llin

g

hole

threads and recoil

cylinder filling plug th

reads for stripping and burs. See 

that purge

plugs are

tight. Note that respirator in

reco

il cylinder is

clean and

operating.

c. The

prescribed 

recoil

oil should be used.

(Refer to para

g

raph 33 for changing from heav

y

recoil

oil to special recoil oil.)

Test the

recoil

oil for wat

er (TM 9-325).

Chec

k for leakage of

 

n

itrogen, as

s

hown

by

emulsified

appearance of reserv

e oil drained

from

  the

recoil

mechanism

(par.

12).

Note whether 

t

he oil index

functions smoothly and indicates

the proper

reserve.

d

.

C

heck for

ex

cessive oil

leakage

at

oil

in

dex, filling plug,

and

recoil stuffing

box head. NOTE: The

recoil stuffi

ng

box

packings

normally

permit

a

slight leakage

of

oil

which insures

lubrication.

How

ever,

if

clear oil leaks past the pac

kings,

th

e

leakage

is

excessive.

e.

Check  tightness of

recuperator and recoil cylinders in

front

sleigh yoke.

Two special box

-spanner wrenches (fig. 23) are pro

vided for

tightening

the

cylinders.

CAUTION:

T

he spanner

wrenches

41-W-3294-100 and 41-

W-3294-75 are to be

u

sed tor tight

ening the

cylinders

o

nly, not

for

dismounting

the cylinders.

{.

Meas

ure

pressure of compressed

nitrogen (par.

11).

11

M

A N O M E T ER TESTS

a. Pur

pose  The

manometer

tes

t determines the nitrogen pres

sure

 

in

the

rec

uperator cylinder. Frictio

n

of t

he floating piston and

 

combined friction of

the recoil piston and stuffing box wi

ll not

be con

sidered as affecting

serviceability. Previously,

inspection

of

the recoil

mechanism has

provided for

the

determination of

frictions

by the

manometer test, and when

above or below .certain limits

the mecha

nism 

was

declared

unserviceable.

Present regulations presc

ribe that

mechanisms will .not be declared

unserviceable because of

friction

determina

tions.

The

nitrogen pressure i

s determined in the field

by

the

indirect method, that

is,

by

 

me

asuring

the pr

essure transmitted

to

the oil by the compre

ssed nitrogen through the medium of the floatin

g

piston. 

The gas

pressure,

when

determined by the

direct

meth

od,

that is,

w

ith

th

e gage tapped directly

 into

the

 nitrogen

chamber

(arsenal

operation only), will differ

by approximately

15 pounds

per

23

8/19/2019 TM9-1325 105mm Howitzer

29/219

TM 9-

1325

O R D N N C E

  M A I N

T E N A N C E

05 M M H O

W I T Z E R S M 2

A

N D

M 2

A 1 ;

C R R I G

E S   M 2 A 1

A N D  

M

2 A 2 ;

A N D  

C O

M B A T

V

E H I C L E

M O U

N T S

M 3

A N D   M4

square

 inch

fro

m

pre

ssure ob

tained

b

y the

indirect

method,

due

to

the

fact

that

the

volume

of

the

nitrogen 

chamber

is 

decreased slightly 

when the oil re

serve

is

prese

nt in th

e mec

hanism, as it

is when 

the

indirect  m

ethod is u

sed. In amoun

t,

th

e

reVenfe oil represents

a vol

ume co

rresponding

 

to the

m

ovement o

f the 

floatin

g

piston

of about

one-half inc

h. Re

serve oil

normal

ly

se

parates

the floating

 piston 

from the regulator

. Compresse

d

nitrogen within

the system

for

ces

the 

floating

 

piston ag

ainst the res

erve oi l

, creating

 

p

ressure on the

oil.

Oil

pressu

re exists

 

only

as lon

g

as th

ere

is

oil

betwee

n the

r

egulator

and

floating

piston

; 

theref

ore, the oil

  reserve m

ust be

 

pre

sent w

hen

making 

the

indirect test.

b. Nitrogen

Pressur

e

1)

The

 

initial

nitrogen pr

essure i

n the mechanis

m is

1,100

poun

ds per sq

uare inch

 at 7

0°

F

 without

reserve oil.

ith re

serve

oil, the

initial pressu

re will b

e

appro

ximately

15 poun

ds per sq

uare

inc

h higher

or 1,

115

po

unds pe

r square inch

at 70° F.

 

Varia

tion

is

appr

oximately 2.

07 pou

nds per s

quare inch

for each

  degree Fa

hren

hei

t) change in te

mperature.

The

  table

b

elow represents

  norm

al

nitro

gen press

ure

wit

h the

 

re

serve oil pr

esent:

Nitrog

en Pres su r

es at Different 

Temperatures

wi

t Reserve

Oil

T

emperature

Tempera

ture

Pr

essure

Centigrade)

Fahrenheit)

pound

s per

squa

re in c

h

0

 

3

1

36

5

41

1,055

10

50

  5

 

5

9

20

68

25

77

30

86

35 

95

,073

,092

 111

,130

,148

,167

 186

0

1

04

45

113

1,204

5

0

122

1,223

55

131

1,242

60

1

40

1,260

c.

Procedu

re

1) 

GENERAL  

Oil

within

the

mechanism becomes

sluggish 

at

low

tempera

tures,

hence its actio

n

th

rough the

smal

l

orif

i es

is

erra

tic and

the reliabi

lity of measur

ements

is dou

btful. When

pressure mu

st be

measure

d in

cold weather,

 

bot

h th

e recoi

l

mechanis

m and

extra recoil

o

il

m

ust

be kep

t in a

 

room w

armed to

at least 

50° F for 24

 

ho

urs

p

receding the

test. Provid

e a clea

n pla

ce to lay all

tools

an

d equip

 

ment re

quired. See

that all

tools

, containers

,

and o

il are

free from 

s

and or dirt.

Contamina

ted oil

must not

be put in

to the mecha

nism.

8/19/2019 TM9-1325 105mm Howitzer

30/219

T

 

9

 

1

3

2

5

 

IN

S

P

E

C

T

IO

N

VI

 

CO

o

 

D

>

1  

0>

 

8/19/2019 TM9-1325 105mm Howitzer

31/219

TM

  9 1

325

 

ORD

NANC

E

MA IN

TEN A

N C E

05-M

M

HOW I

TZERS

 M2 A N

D

M

2A1;

CARR

IAGES

 M2

A T A

ND

M2A2

;

A

ND

CO

MB A

T V tH

ICLE   M

OUNT

S M3

A N D

 M4

R P

D 45  9

Figu

re

77 —

 Refra

cting

  Jack

 

in

P

ositio

n

for Re

tract

ing

Ho

wifz

er

T

ube

RA PD

  87859

Fig

ure

8 

Meas

uring

 Nitr

ogen

 

Pre

ssure

 With

 H

owitz

er Tube

 

in

Pla

ce

26

8/19/2019 TM9-1325 105mm Howitzer

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T M 9 1325

INSPECTION

(2) USING

T H E R ETRACTING JACK.

 a) Bring

the

how i

tzer to

zero

degree ele

vation. See that the

recoil slides

are clean

and

well

lubricated.

 b)

Connect the retracting jack

41-J-1 59-160

(figs.

16 and 17).

 c)

Remove

the

plug fro

m

the recuper

ator

c

ylinder front

head

and

screw in

its place oil

releasing tool 4

1-T -3 251-611

(fig. 18).

D

raw

off any

 

oil

reserve that may be

in

the mechan

ism and catch it

in

the thermom

eter cup. After

se

veral minutes, read and record

the

te

mperature. The thermometer

 

read

ing is

the

tem

perature in s

ide

the

recoil

mechanism.

 d) Attach

the

pressure

gage connection and t

he

press

ure g

age

45-G-290

to

the

end 

of

the

oil

releasing tool

but

do

not

tighten.

 e)

Turn the crank until

oil

 leaks

from around the

thr

eads o

f

the

plug. This w il

l

pu

rge the line (remove air from the oil). Tighten

the plug.

NOTE:

All 

joints

must

be

absolutely

oil tight when making the

test.

 f)

At this

point, the

end

of the 

oil

index in recuperator cylinder 

head

will

be

near the bottom of the cou

nterbore which

 

indic

ates no

re

serve.

By

 turning the

crank,

retract

the howitzer until the oil

index

stops

moving.

At this

point, the

oil

index will be slightly beyond  the

face

of

 the

cylinder

head w h

ich

indicates

full

reserve.

 

Wh

ile

turni

ng

slowly—at

  the

rate of

four

turns

per

minute—

read the gage. The

gage

h

and will be

stationary and the

reading

will

represent

P + F, or

gas pressure plus

floating piston

friction.

CA

UTION:

Re

adings

must

be

taken

as

close

to the

exact

time the  index stops moving as

p

ossible

and the

gage should be tapped light

ly with finger

s

to insur

e

that

the

gage hand

movement

is complete.

  Continue to turn the crank

approximately five

more turns.

 g)

R

everse

the

mo

tion of the crank to counte

rclockwise 

and

while turning

at the

s

ame rate—four turn

s

per minute—rea

d the gage

when the

gage

hand

becomes s

tationary (at

app

roximately the fifth

turn). This reading r

epresents P — F or gas pressure min

us

floating

piston

friction.

 

h) Example—co

mputation of gas pressure

:

Temperature of

re

coil oi

l (step

c),

above) .............................

.......

6

8° F

Gage rea

ding,

P F (step

 

C/J, abo

ve) .............

..........f................ 1,235 psi*

Gage readin

g, P.-F

(s

tep g),

above) ............................

............ 1,037 psi*

Add 

these

gage

readings together

..................................................

2,272

psi*

Then divide by

2 ........................................................................

......

1 ,1

36

psi*

Gage

pressure is con

sidered

satisfac

tory

at 125

pounds 

per

square

in ch above or

below the

pressure

shown

in table I

for

correspond

ing 

temperature

readings. The table shows

 

that

at 68° F the 

pressure

should

be

1 ,1 11 pound

s

per

square inch.

A llowable limits

  for this

  Pounds  per square inch

27

8/19/2019 TM9-1325 105mm Howitzer

33/219

TM

9-13

25

O R D N A N C E M A I N T E N A N C E 05 MM

H O W I T Z E

R S M2 A N D M2A1;

C A R R I A G E S M2A1

A N D M2A 2; A N

D

C O M

B A T V EHIC

L E M O U N T S

M

3 A N

D

M4

temperature

are from 986

pounds per squ

are inch

to 1,236 pounds

per square

inch.

The

reading

1,136

pounds per

square

inch

falls

within this

r

ange

and is therefor

e

acceptable

. Should

the pressure

no

t come with

in this range,

replace the  recoil mechanism

.

(3)

U S IN G S C R E W J A C K

.

 a)

Level the

 

sleigh

and cradle and

remove the

howitzer

from

the

carriage.

 b)

Disconnect recoil 

piston r

od by removing

recoil piston rod

outer

nut.

 c) Push

 

sleigh

back on cradle guide

s

until

rea

r en

ds

of sleigh

rails project back 

of

the rear

end of the

cradle about 5 or

6

in

ches.

 d

) 

Remove recoil cylinder

respirator assem

bly

B19

5116, using

wrench

 

41

-W-1999-300 (fig.

19).

 e)

 

Assem

ble screw jack in

the rea

r

of

  the recoil

cylinder and

screw the nut

up firmly

against th

e

recoil cy

linder (fig. 20

).

NOTE

:

Before installin

g b

e

su

re the

s

crew of

the jack is backed out u

ntil

the

jack hea

d contacts the

nut.

 f) Drain

  the reserve

oil, install the pressu

re

ga

ge (f i

g.

2

1), and 

proceed

as

described

in

subparagraphs

c

(2)

c)

through

c

(2)

h),

ab

ove.

NOTE: Operation of

the screw j

ack will retr

act

the recoil

mechanism

on

ly, 

since the h

owitzer was

removed from the

carriage

in

step

 (3) a), ab

ove.

d.

De

termination o

f

Service

ability or

Unserviceab

ility of

Re

 

coil

Mechanisms Recoi

l m

echanisms

wi

ll not be cond

emned as

un

se

rviceable becaus

e o f

low

nitrogen pr

essure u

ntil

the

mechanism  h

as

bee

n

test-fire

d,

except when

 

the

  loss in pressure is

  such that firing

might re

sult

in d

amage  to

the

r

ecoil mechanism. The

following de

tailed

steps 

will

be

taken

in 

analyzing

the serviceability

of a

recoil

mechanism

  with low pressure.

(1)

If results

of the  m

anometer test indicate

that the minus

deviation

from  normal p

ressure (table

I) is le ss

th

an — 1

00 pounds

per square inch, the

mechanism

 

will

 

be

 considere

d serviceable w

ithout

further test.

(2) If

the minus deviation

is grea

ter

than

— 1 00 pounds

per

squa

re

in ch

, the

mechanism will

 

be

test-fired, exc

ept when

 

th

e

deviation

is

greater than

— 1 5 0

pounds per square

inch.

(3)

Mechanism

s with

pressure lo ss greate

r

tha

n

— ISO

. pou

nds

per

 

squ

are inch will be

considered un

serviceable

without

furth

er tests.

(4)

To

test-f

ire, the

mechanism will be

fired one

round maximum

charge at 10

degrees elevation.

If the length

of recoil exceeds

42

inches,

firing will cease a

nd the m

echanism

w

ill be

considered  un

servi

ceable. I

f the mechanism function

s 

satisfactorily when fire

d

at

28

8/19/2019 TM9-1325 105mm Howitzer

34/219

TM 9-13

25

IN S

P E C T IO N

RA

PD 80075

Fig

ure

19

— Recoil Cylind

er Respirator

10 degrees elevat

ion, it

will then be fired at

50 degrees elevation

.

If

the length of

recoi

l ex

ceeds 43  A inche

s, the

m

echanism

will be con

sidered unser

viceable.

(5) The

length  of

r

ecoil

will be measu

red

on all 

test rou

nds an

d

counter

recoil action  should b

e carefully ob

served, since the usual

effec

t

of low nitrogen p

ressure is 

f

ailure

to

return 

to

ba

ttery.

Coun

terrecoi

l

should

be smooth,

and return into

battery should

be com 

ple

te and

with s

mooth buff

er

action,

tha

t

is,

without slam

or shock. 

If the

mechanism functions

satisfactorily

as

determined

by

test-firing,

it will be considered

serviceable. A

 

mec

hanism which

fails

to

func

tion satisfactorily

will be declared unservic

eable.

If

d

oubt as to serv

iceability exist

s, further rounds should

be fired

as

de

emed  necessa

ry.

(6) If the 

lengt

h of

reco

il

is

44Vi inches 

or more,

permanent

damage will occu

r due to

 

metal-to-m

etal c

ontact

betwee

n th

e

recoiling

 

parts

and

the

nonrecoi

ling parts

.

29

8/19/2019 TM9-1325 105mm Howitzer

35/219

TM 9 1325

O

R D N A N C E

M

AINTENANCE 05-MM H O W I T Z E R S

M2 AND M2A1 ;

C A R R I A G E S

M2A1

AND

M 2 A 2 ; AND COMBAT

V E H I C L E MOUNTS

M3

AND M4

RA PD 19390

Figure 2

  — Using

 

Screw J

ack in

Manometer

Test

(7

) If

test-firing

cannot

be accomplished becaus

e of

inadequate

facilities,

disposition

will be

requested of the

Chief

of Ordnance

(Zone

of

Interior) or Chief

Ordnance

Officer

(Theater 

of Operation) on

all

mechanisms

which 

require

test-firing

within

the 

provisions

of

the

above

paragraphs.

e. Evacuation 

of Recoil Mechanisms.

Imm

ediate evacuation of

unservic

eable recoil

m

echanisms through

normal

ordnance channels

i

s to be

accomplished, as a continuing 

supply

of

mechanisms

de

pends

on

 prompt evacuation

 

of

unserviceable

 

mechanisms to overhaul

facili

ties.

Precautions

will

be

ta

ken to see that the

assembly arrives un 

damaged

from corrosion

 

or

handling. All exposed and threaded

por

tions

of

th

e mechanism, including the recoil

piston rod,

will

be

cov

ered

with preservative material. T

he respirator

will

be

sealed

with

tape.

The recoil piston ro

d

will

be wired

in place

to prevent dis

placement

in

transit. Recoil mechan

isms

will

be evacuated

 

in crat

es

or

boxes

similar

to those in

which they are

received.

Crates

are to

include

supp

orts to

pre

vent 

bending of

r

ecoil piston

rod.

30

8/19/2019 TM9-1325 105mm Howitzer

36/219

TM 9-1325

1 1

I N S P E C T I O N

4

4 )

N

 

£

2

i n

0 )

D >

D

0)

O )

31

8/19/2019 TM9-1325 105mm Howitzer

37/219

T

M 9 1325

12 13

O R D N

A N C E MAINTENANCE-

105-MM HOWITZERS M2 AND

M2A1;

C A R R I A G E S

M2A1 AND M2A2 ; AND COMBAT V E H I C L E MOUNTS

  M3 AND M4

12.

E M U L

SIFIED OIL.

a.

Emulsified

oil

in

a

hydropneumatic

recoil mechanism may be

due to

eith

er or both of the following

causes:

(1)

IMPROPER

FILL

ING TE

CHN IQUE.

Re

establishing of the re

serve oil

may

cause

some

air to be forced into

the mechanism. In

this

case,

the emulsion

will

usually not be excessive and will

not affect

the  se

rviceability

o

f the mechanism. Repeated forcing

of air into the

recoil oil

during rees

tablishment of the

re

serve oil will result in a

serious emulsification of the

oil which

wil

l

affect

the recoil

and

coun-

terrecoil

action

of the me

chanism.

(2)

NITROGEN

LEAKAGE

PAST

THE FLOATING

PISTON. 

In

cases

where the nitrogen is

leaking

past

  the floating piston

, the degree of

the emulsion may be such as

to cause overreco

il

a

nd

an unsteady

thr

ottling

eff

ect resulting in sud

den and serious strains

to

the recoil

me

chanism.

b.

I

f the oi

l

released from

the recoil

mechanism

comes ou

t

sput

tering and foaming, there is probably a

leakage of nitrogen past the

float

ing piston. If there is

any doubt as to whether the

emulsification

is d

ue to

a

leakage of

nitrogen

past the floating piston,

the mechanism

should be

completely

drained

of

the

emulsified recoil

oil

and

refilled.

If

the recoil o

il again becomes emulsified, nitrogen is

leaking

past the

floati

ng piston.

c. Leakage

 

of

 

n

itrogen past the floating

piston resulting in em

ul

sificat

ion of the recoil oil

may or may not be

indicated by low ni

trogen

pressure. A combination of

low

nitroge

n pressure and exces

sive

emulsification of the recoil

oil

is

a

good

indication

of leakage

past the floating pisto

n. Leakage of

nitrogen

past

the floating piston

is

a progressive co

ndition

which

can only be corrected by  overhaul

in

authorized recoil

overhaul shops. If it

is established that

em

ulsifica

tion of the recoil

oil

is due

to leakage past the floating pist

on, the

recoil mechanism will be decl

ared unserviceable.

13.

MAINTENANCE

OF

  RECORDS

FOR

R EC OI L

 

MECH

A

NISMS.

a. A

complete and

accurate

rec

ord

of recoil 

mechanisms must be

kept in

the

Artillery

Gu

n

Book O.O.

Form 5825).

The

following 

information

should be entered:

(1)

The

serial num

ber,

m

odel number, co

mplete

designat

ion,

manufac

turer,

date of

manufacture, and

period

of service

.

(2)

Record of all Modificatio

n

Wo

rk

Ord

ers performed on recoil

mecha

nism.

(3)

Record of

al

l parts broken,

repaired,

or

replaced.

(4)

Complet

e

record of  all inspections.

32

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TM 9-13

25

INSPECTION

b. If

the recoil mechanism

is separa

ted from the

 

howi

tzer, the

records pertaining to

it shall

be

ex

tracted and kep

t with the item

.

These

records

will

be

entered

on 

a

plain sheet

of

paper,

headed 

R

ecoil

Mechan

ism Record, a

nd will include

the following informa

tion

(1)

  Se

rial

num

ber, mod

el

numb

er, complet

e design

ation,

manu

facturer, date o

f manufacture

, and period of  s

ervice.

(2) Caliber,

 

serial n

umber, m

odel number,

designation, manuf

ac

turer,

 

and

date  of

 

manufa

cture o

f

wea

pon with

which the recoil

mechanism

was

 

u

sed.

(3)

Number of

rounds fi

red

w

hile recoil mechanism

was

in 

use.

(4)

All entr

ies

made in

gun book

pertai

ning to

subject recoil

mechanism.

c. At 

the

time

a recoil mechanism

is declared u

nserviceable,

the

ca

use 

will

be entered 

in

the

 records and

signed and dated by

 

th

e

condemning

 officer.

d.

Whe

n the re

coil mechanism is to

be shipped,

 the recoil mecha

nism record

will be placed

in

a

  waterproof

envelope a

nd attach

ed

securely to th

e mechanism with wate

rproof t

ape.

e.

The recoil mechani

sm record will

be at

tached

to the

r

ecoil 

mechanism

when it is pl

aced in storage.

f.

Whe

n 

the

re

coil

me

chanism

is

aga

in ma

ted with a weapon,

the

info

rmation contain

ed on

the rec

oil

mechanism

record 

will be entered

in the g

un

boo

k for that weapo

n.

14. CARRIAGE IN GE

N ERAL

a. Examine

condition

of all welds and

rivets.

See

that

there are

no loose, broken,

or mi

ssing

plates,

bolts, nu

ts,

screws,

or cotter p

ins.

Check that all

exposed parts

 

are cle

an, free  fro

m

rus

t, and properly

lubrica

ted.

See that all

parts

are

  properly

adjusted and

tightened.

Note wh

en the ca

rriage

wa

s last

exercised

.

b.

Pay particular atte

ntion

to

condition of pa

int

and

 general

state

of

preservation. Note that

pai

nt has not deteri

orated or becom

e

damaged

, leaving

exposed por

tions

o

f bare or shiny

surfa

ces

a

nd

necessitating repain

ting.

See

th

at prescribed

surfaces are

well coated

and

that

there

is 

no 

paint

on

the 

bearing

surfaces.

Necessary

letter 

ing should

be in

blue

-drab luster

less

s

ynthetic

enamel. Lettering

 on

n

ame pla

tes and direc

tion plates should

be legible.

c. Lubricating

fittings shou

ld be clean and s

hould  functio

n

prop

erly.

The

y

sho

uld be

identified by

3

/4-inch red circles

.

d.  Note whe

ther all

Modification

 

Work

Orders have

  been

per

formed.

33

8/19/2019 TM9-1325 105mm Howitzer

39/219

T

M 9 1325

 

1

5 16

O R D N

  N C E

M A

IN T E N A N C E

0 5 M M

H O W I T Z E R

S

M

2 A N D M2A1;

C R R I G E

S M 2A

1

A N D

 

M 2 A

2 ; A N D

 

C O M B

A T

V E H I C L E   M O U

N T S M 3 A N D

M4

15  LUNETTE

 

ND

 

D

RAWBAR

  par.

75).

a.

Inspect the lunette

for

condition,

particularly

for

excessive 

wear

of loop, and t

ightness in

 drawbar.

b. Check

rotational

mov

ement

of

drawbar

 

as

sembly. Th

is

ass

em

bly

should 

be free

and

movement

 

should be

 u

nobstructed

.

Exa

mine

drawbar for cr

acks in

metal and for

bent

 

p

ortions. Try dra

wbar lock

 

for hard

 places id

for

obstruc

tions

or

undue

 

lo

oseness in the

back

 

and fo

rth

m

ovement.

16

SPADES

ND 

TRAILS sec.

XIV).

a.

Examine spades for

 crack

s

an

d distorti

on, conditio

n of we

lding

and re

inforcemen

ts, loose rivets

, a

nd

excessive

  we

ar of met

al

in

points.

b.

Examine

 

trails fo

r  straigh

tness and w

elding alon

g the

 

seam

s.

Exam

ine trai

l handle,

handspik

e

bra

cket, c

leaning staff s

upports, aim

i

ng

post supports,

han

dspike

b

ody,

and cleanin

g staff

br

acket for

 

c

on

dition of w

elding. Inspe

ct

tra

il

traveling lock lo

op,

p

in,

and cotter

 

pins

for

wear

and

damage.

Try

trail

traveling

lock 

handle,

hook,

and

latc

h. Latch sh

ould

b

e free,

but  not

loose.

Note

th

at han

dles and

levers of sta

ff suppo

rts press down

 withou

t effort and go a

ll the way

down.

  Note

that quick

  opening devic

es which

hold 

handspike

 

in

traveling

position

 

fu

nction

properly

.

c. Check

traveling

lock b

rackets  for p

roper 

adj

ustment

an

d

cor

rec

t alinem

ent

w

ith tr

aveling 

l

ock sh

aft pieces.

d. Mov

e

lef

t trail

to op

en

an

d close

d position

  by

u

se  of h

and

spike.

Move

right trail to

open  and

closed

position

using

drawbar.

The

  trails

shou

ld

o

pen an

d

c

lose 

without

exce

ssive pla

y or

bind

ing

at trail

hinge

p

ins. S

ee that hinge

 

pins

are

 properly

 

lubr

icated

and

not scored

 

or badly

 worn.

e.

Check

 tolerance

s

of trail

 hinge

pins as follow

s:

Unlock  trail

trave

ling

lock

assemb

ly and

 open trails

to a parallel

 position, m

aking

sure tha

t traveling lock

shaft pieces

 and trave

ling lock

brackets

are

not engaged.

  Fasten

  a rope loo

p arou

nd

the r

ear end of

  the

trail.

Attach to 

hoist

and 

raise

until  trail

clears

the

floor 

approximately

2

in

ches. Ta

ke

hold of spade a

nd mov

e

trail 

up and d

own. I

f

a

ny

mo

vement is

noted other than

 

the nat

ural

spring

 

in the

tr

ail, measure

 

clearan

ce between

 

trail

hinge p

in

a

nd  equa

lizing sup

port par. 73).

f. Cle

arance betwe

en

the

bearing

surface on th

e front end

of the

t

rail

and

th

e ax

le

lock 

lever

  assembly

should be 0.0

04

inch

. A

piec

e

of

notebook

 

paper

is approxi

mately 0.004

 inch

 

thick.

34

8/19/2019 TM9-1325 105mm Howitzer

40/219

TM 9

-1325

17-1

8

INSPECTION

17

.  AXLE EQUALIZ

ING SU P

PO RT W HE

ELS AND

TIRES.

a. Inspect

axle and equalizing

support

 

for

alinement.

A

bent

axle or

equalizin

g support should be

replaced

(se

c.

XV).

b. Inspe

ct welding

around tow hooks

and all

machined

surfac

es

noting

burs and rust spots.

 

c. Rot

ate axle 

lock

 

lever

asse

mblies to

  open and  closed

positions.

Assemblies

should operate  freely

. Note any burs, rust spo ts,

or

ex

cessive looseness.

L

ock shaft

gui

de screw

 A157025 and nut BB

DX1E

s

ometimes become loose and wo

rk down

obstruc

ting movement of the

traveling

lock

assembly.

These 

are to 

be

adjusted

in 

the manner

prescribe

d

in

paragraph 8 3.

d.

Clearanc

e between equaliz

ing support

gib

bearing

s should

be

approximate

ly

0.004

inch

 

for ease

of movement

during  firing.

This

may  be determ

ined by in

serting a piece of not

ebook paper

between

 

the bearing

surfaces.

e

. To check the

hand brakes,

it

is

necessary to

jack up  the wheels.

Using

one hand, spin the

wheel vigoro

usly;

a

t the sa

me

t

ime, using the

other

hand,

slowly

pull

back

on

the hand brake

lever

assembly,

feel

ing the brake take

hold a

nd

observi

ng the

reaction  on the wheel.

The brake when

properly adjusted

  should be

gin to

take 

hold w

hen

the leve

r assembly

has

moved

about inc

h from the off

position

and the wheel

should be comp

letely

stopped

in

approxi

mately one

more

inc

h o f trave

l.

f. Wheels wil

l

first

 be

checked for alineme

nt. Wheels out of

alinement will cause u

neven w

ear

o

f

the 

tires. (This

is us

ually the

first indic

ation.) The straightness of the

  wheels and

  rims and

  tight

ness 

of

the 

lug

nuts

are to 

be

noted.

Note 

that

valves are serviceable

and have valve

 

caps.

g. Tires

are to be ins

pected for

breaks