INTRODUCTION - MyGradall.commygradall.com/pdf/service_manuals/80804003_Mechanical Adjustment.pdfINTRODUCTION This manual is a ... THE ROLL TEST The purpose of a roll test is to determine

INTRODUCTION

This manual is a step-by-step guide to assembly and dis-assembly of torque-hub units. It is designed for the customer orshop mechanic who is repairing a particular model of torque-hubfinal drive. Users of this manual should note that each partmentioned is followed by an indentification number enclosed inparentheses. These part numbers may be referred to in the PartsList section of this manual and on the cross-sectional view of thisunit. A print of each tool discussed in this manual is shown in theTooling section. Users should familiarize themselves with theprocedures for roll and leak testing and bolt tightening andtorquing found on the following two pages before getting started.

This manual includes the following sections.

1. Roll and Leak Testing Procedures

2. Bolt Tightening and Torquing Procedures

3. Disassembly Procedures

4. Sub-Assembly Procedures

5. Main Assembly Procedure

6. Drawings of all Essential Tools

7. Parts List

8. Cross-Sectional View of the Unit

SAFETY

Standard safety practices should be followed during thedisassembly and assembly procedures described. Safety glasses andsafety shoes should be worn. Heavy, heat resistant gloves should beused when heated components are handled. Be especially alert whenyou see the word CAUTION. This indicates that a particularoperation could cause personal injury if not performed properly orif certain safety procedures are not followed.

I

ROLL and LEAK TESTING

Torque-hub units should always be roll and leak tested beforedisassembly and after assembly to make sure that the unit’s gearsand sealants are working properly. The following information brieflyoutlines what to look for when performing these tests.

THE ROLL TEST

The purpose of a roll test is to determine if theunit’s gears are rotating freely and properly. You shouldbe able to rotate the gears in your unit by applying aconstant force to the roll checker. If you feel more dragin the gears only at certain points, then the gears are notrolling freely and should be examined for proper install-ation or defects. Some gear packages roll with more diffi-culty than others. Do not be concerned if the gears inyour unit seem to roll hard as long as they roll withconsistency.

THE LEAK TEST

The purpose of a leak test is to make sure that theunit is air tight. You can tell if your unit has a leak ifthe pressure gauge reading on your air checker starts tofall once the unit has been pressurized. Leaks will mostlikely occur at the main seal or wherever “O” rings orgaskits are located. The exact location of a leak canusually be detected by brushing a soap and watersolution around the main seal and where “O” rings orgaskits meet the exterior of the unit then checking forair bubbles. If a leak is detected in a seal, “O” ring, orgaskit, the part must be replaced.

II

TIGHTENING and TORQUING BOLTS

If an air impact wrench is used to tighten bolts,extreme care should be taken to insure that bolts are nottightened beyond their indicated torque specification.Never use an impact wrench to tighten shoulder bolts, allshoulder bolts should be tightened by hand.

The following steps describe the proper procedure fortightening and torquing bolts or socket head cap screwsin a bolt circle.

1. Tighten (but do not torque) bolt“A” until snug.

2. Go to the opposite side of the boltcircle and tighten bolt “B” untilequally snug.

3. Continue around the bolt circleand tighten the remaining bolts.

4. Now use a torque wrench to applythe specified torque to bolt “A”

5. Continue around the bolt circleand apply an equal torque to theremaining bolts.

III

MAIN DISASSEMBLY

1. Remove pipe plug (15) from cover(6)and drain the oil from the unit.

2. Roll test the unit in bothclockwise and counterclockwisedirections. Perform the same numberof turns in each direction as theratio of the unit. The ratio number isthe same as the last two digits in themodel number found on the ID tag ofthe unit.

3. Leak test the unit at a pressure of5 psi for 2-3 minutes.

4. Remove all 24 grade 8 bolts(16)from cover(6).

1

5. Lift cover(6) off of hub(1G) andremove “O” ring(5) from the counter-bore in the cover. Discard the “O”ring.

6. Remove small thrustwasher(7) fromthe counterbore in the center hole incover(6).

7. Remove large thrust washer(14),thrust bearing(13), and large thrustwasher(12) from the raised insidecircular edge of cover(6).

8. Remove input gear(8) from meshwith the planet gears in first stagecarrier assembly(3).

9. Lift out first stage carrierassembly(3).

2

10. Remove small thrust washer(9)from the top of second stage sungear(11).

11. Remove thrust bearing carrier(10),large thrust washer(14), thrust bear-ing(13), and large thrust washer(12)from the counterbore of second stagecarrier assembly(2).

12. Remove second stage sun gear(11)from mesh with second stage carrierassembly(2).

13. Lift out ring gear(4).

14. Remove “O” ring(5) from thecounterbore in hub(1G) and discard.

3

15. Lift out second stage carrierassembly(2) from mesh with outputshaft(1A).

16. Using retaining ring pliers,remove retaining ring(1L) from groovearound the outside of output shaft(1A).

CAUTION: Safety glasses should beworn during this procedure.

17. With a screwdriver or chisel andhammer, straighten out the tang onlockwasher(1J) which has been bentinto the notch on locknut(1K).

18. Using an AN-18 locknut wrench(tool no T-156766), loosen locknuts(1K). Remove the locknut from outputshaft(lA) and discard.

NOTE: The output shaft must be heldsecurely enough to resist turningwhen the locknut is loosened.

19. Remove lockwasher(1J) and tangedwasher(1H) from output shaft(1A).Discard the lockwasher.

4

5

20. Raise hub(1G) above your worksurface and support it fromunderneath in a manner that willallow output shaft(1A) to fall throughthe bottom. Press the output shaftout of the hub. The output shaft willcome out with bearing cone (1D)attached and seal(1B). Discard theseal.

21. Remove bearing cone (1D) fromoutput shaft(lA).

22. Lift bearing cone(1F) out ofhub(1G).

23. Using a soft punch and hammer,remove bearing cups (1E) and (1C)from hub(1G). Be very careful not tostrike the counterbores of the hubwhere these cups are located whenusing the punch.

24. Remove all four pipe plugs (1M),(1N), and (1P) from hub(1G).

25. At this point the main disassemblyis complete.

FIRST STAGE CARRIER DISASSEMBLY

1. Locate dowel pin(3D) which holdsplanes shaft(3E) in carrier housing(3A).

2. Drive the dowel pin(3D) down intoplanes shaft(3E) until it bottomsagainst the carrier housing. If thedowel pin is not completely driveninto the planet shaft, damage to thecarrier could occur when the shaft isremoved.

3. Remove planet shaft(3E) fromcarrier housing(3A). The four thrustwashers(3B) and planet gear(3F) willslide off.

4. Using an alignment punch andhammer, drive dowel pin(3D) outthrough the end of the dowel pinhole in planet shaft(3E) that itoriginally went into.

6

5. Remove needle rollers(3C) frominside planet gear(3F).

6. Repeat steps 1-5 to remove the two remaining planet gears.

7. At this point the first stage carrier disassembly is complete.

7

SECOND STAGE CARRIER DISASSEMBLY

1. Locate dowel pin(2G) which holdsplanet shaft(2E) in carrier housing(2A).

2. Drive dowel pin(2G) down intoplanets shaft(2E) until it bottomsagainst the carrier housing. If thedowel pin is not completely driveninto the planet shaft, damage to thecarrier could occur when the shaft isremoved.

3. Remove planet shaft(2E) fromcarrier housing(2A). The four thrustwashers(2B) and planet gear(2F) willslide off.

4. Using an alignment punch andhammer, drive dowel pin(2G) outthrough the end of the dowel pinhole in planet shaft(2E) that itoriginally went into.

8

9

5. Remove needle rollers(2C) andspacer(2D) from inside planesgear(2f)

6. Repeat steps 1-5 to remove the two remaining planets gears.

7. At this point the second stage carrier disassembly is complete.

FIRST STAGE CARRIER SUB-ASSEMBLY

1. Apply grease to the inside of onefirst stage carrier planes gear(3F).

2. Line the inside of planet gear(3F) with 19 needle rollers(3C).

3.Stand first stage carrier housing(3A)in an upright position.

4. Insert a planet shaft(3E) intoone of the planet shaft roles whichhas a dowel pin hole on carrierhousing(3A). The end of the planetshaft that does not have the dowelpin hole should be inserted into thecarrier housing first.

10

NOTE: One end of the dowel pin hole on the planet shaft has achamfer or gradual slope. This end should be up to allow easyalignment.

11

5. Place two thrust washers(3B) ontothe end of planet shaft(3E) whichhas been inserted through the planetshaft hole in carrier housing(3A).

NOTE: Grease or petroleum jelly maybe used to hold the washers togetherand in place on the planet shaft.

6. Following the thrust washersplace planet gear (3F), with needlerollers, onto planet shaft (3E).

7. Following the planet gear, placetwo more thrust washers(3B) ontoplanet shaft(3E).


8. Now insert planet shaft(3E)through the opposite planet shafthole on carrier housing(3A).

9. Using an alignment puch orsimilar tool, align the dowel pinholes on carrier housing(3A) andplanet shaft (3E).

10. If you examine a dowel pin (3D)carefully, you will notice that oneend is smaller than the other. Drivethis end of the dowel pin (3D) downinto the aligned dowel pin holes. Itshould be driven to just below (1/10in.) the surface of the carrierhousing.

ll. Repeat the procedure in steps 1-10 for installation of thetwo remaining first stage planes gears(3F).

l2. At this point the first stage carrier sub-assembly is com-plete.

12

SECOND STAGE CARRIER SUB-ASSEMBLY

1. Apply grease to the inside of onesecond stage planet gear(2F).

2. Line one half of planet gear(2F)with 18 needle rollers(2C).

3. Place one spacer(2D) insideplanet gear(2F) so that it rests ontop of the needle rollers (2C).

4. Line the remaining half of planetgear(2F) with 18 needle rollers(2C).

13

5. Stand second stage carrier housing(2A) in an upright position.

6. Insert planet shaft(2E) into aplanet shaft hole that does not havea dowel pin hole on carrier housing(2A). The end of the planet shaftwith the dowel pin hole should beinserted into the carrier housingfirst.

7. Place two thrust washers(2B) ontothe end of the planet shaft whichhas been inserted through the planetshaft hole.


8. Following the thrust washers,place planet gear(2F), with needlerollers, onto planes shaft(2E).

NOTE: One end of the dowel pin hole on the planet shaft has achamfer or gradual slope. This end should be up to allow easyalignment.

14

15

9. Following the planet gear, placetwo more thrust washers(2b) untoplanet shaft(2E).


10. Now insert planet shaft(2E)through the opposite planet shafthole on carrier housing(2A).

11. Using an alignment punch orsimilar tool, align the dowel pinholes on the carrier housing andplanet shaft.

12. If you examine a dowel pin(2G)carefully, you will notice that oneend is smaller than the other. Drivethis end of dowel pin(2G) down intothe aligned dowel pin holes. Itshould be driven to just below (1/10in.) the surface of the carrierhousing.

13. Repeat the procedure in steps 1-12 for installation of thetwo remaining second stage planet gears(2F).

14. At this point the second stage carrier sub-assembly iscomplete.

1. Apply a light coat of “Never-Seize” to the four hub pipe plugs(1M), (1N), and (1P).

Note: Pipe plug(1P) is a magneticplug.

2. With hub(lG) standing on itslarge diameter end, tighten pipeplugs(1M) into the two pipe plugholes nearest the small diameter endof hub(1g).

NOTE: Notice that pipe plugs(lM) aremuch smaller than pipe plugs (1N)and (1P).

3. Turn hub(1G) over so that itrests on its small diameter end andthe two pipe plug holes nearest thehub’s large diameter and are facingyou. Tighten magnetic pipe plug(1P)into the right-hand pipe plug hole.

4. Mark the location of magneticpipe plug(1P) so that it may bealigned with the pipe plug hole incover(6) in a later step.

HUB-SHAFT SUB-ASSEMBLY

16

5. Install pipe plug(1N) into the left-hand pipe plug holenearest the large diameter end of hub (1G).

6. With hub(1G) still standing onits large diameter end, press bear-ing cup(1C) into the small diameterend of hub(1G) usina a bearing cuppressing fixture (tool no.T- 156792).

NOTE: Make sure that the cup sitssquare with the counterbore of thehub before pressing.

7. Turn hub(1G) over so that itrests on its small diameter end.Press bearing cup(1E) down intohub(lG) using a bearing cup pressingfixture (tool no. T-130717).

NOTE: Make sure that the cup sitssquare with the counterbore of thehub before pressing.

8. Spray the inside of bearingcone(1D) with oil.

9. Press bearing cone(1D) onto out-put shaft(1A) using a bearing conepressing fixture (tool no.T-158049).

17

18

10. With small diameter end down,lower hub(1G) onto output shaft(1A).

11. Spray the inside of bearingcone(1F) with oil.

12. Press bearing cone(1F) ontooutput shaft(1A) using a bearingcone pressing fixture (tool no. T-146588). Reduce the pressure appliedto the bearing cone and press thecone again. This time rotate thehub in both clockwise and counter-clockwise directions while pressing.Stop pressing when the hub starts toresist the rotation.

a) Tighten a bolt into one of thebolt holes on the hub. The bolt usedshould be one that fits the hole.

13. Now measure the initial rolling torque of hub(1G). To dothis, follow steps a-d.

b) Place a torque wrench on the bolt so that the arm of thewrench lines up on a tangent to the circumference of the hub asshown in figure 1.

19

c) Keeping the wrench in thisposition at all times, use the armof the wrench to guide the hubaround in one rotation.

14. Place tanged Fwasher(1H) ontooutput shaft(1A).

d) Read the gauge on the torque wrench. The initial rollingtorque should be 25-30 in.-lbs. Measure the rolling torqueseveral times to insure an accurate reading.

NOTE: If the initial rolling torque is less than 25 in.-lbs.,apply more pressure to bearing cone(1F). If the initial rollingtorque is higher than 30 in.-lbs., strike the top of outputshaft(1A) with a soft face hammer to release the load on theshaft, then repeat steps 13b - 13d.

Rolling Torque Procedure

THE CORRECT READING CAN ONLY BE MADE IF THETORQUE WRENCH IS PULLED SLOWLY (APPROX. 3.5 R.P.M.)AND SMOOTHLY TOWARDS YOU.

Figure 1.

20

15. Place lockwasher(1J) onto outputshaft(1A).

NOTE: Notice that lockwasher(1J) hastangs and tanged washer(1H) doesnot.

16. Spray the inside of locknut(1K)and the exposed sides of outputshaft(1A) with Locquic Primer T.Allow two minutes drying time.

17. Apply Loctite 277 Adhesive/Sealant to the second screwthreadfrom the bottom of locknut(1K).

NOTE: The bottom of locknut(1K) hasa chamfered or inward sloping edge.

18. Place locknut(1K) onto outputshaft(1A) and screw into place.

NOTE: Loctite 277 is an anaerobic adhesive. Once it has beenremoved from air, it sets. Therefore, once the locknut has beenplaced on the output shaft, it must be torqued immediately or theadhesive will make it difficult to turn.

21

22

19. Using an AN-18 locknut wrench(tool no. T-156766) and a torquewrench, apply 225 ft.-lbs. of torqueto locknut(1K).

20. Measure the final rolling torqueof hub(1G) using the same mannerdescribed in steps 13a - 13d. Thefinal rolling torque should measure35-60 in.-lbs.

NOTE: Remove the bolt from the hub.

21. Bend the aligned tang onlockwasher(1J) up into the notch onlocknut(1K).

22. Using a center punch and hammer,stake locknut(1K) in four equallyspaced positions around the cir-cumference of the locknut and at adistance of 1/8 in. from the insideedge of the locknut.

23. At this point the hub-shaft sub-assembly is complete.

NOTE: One tang on lockwasher(1J) must line up directly with onenotch on locknut(1K). If one tang does not line up with alocknut notch, apply sufficient increased torque to the locknutuntil it does. Never loosen the locknut.

1. Turn hub(1G) over so that itrests on its large diameter end.Spray oil on all exposed surfacesinside the hub while turning outputshaft(1A).

2. Spray the inside of seal(1B) withoil.

NOTE: The open face of the seal mayhave a waved surface. This is anintentional design used to keep dirtout.

3. Press seal(1B) into the smalldiameter end of hub (1G) using a sealpressing fixture (tool no.T-156799).

4. Turn hub(1G) over once again sothat it rests on its small diameterend. Using retaining ring pliers,insert retaining ring(1L) into thegroove on output shaft(1A).

CAUTION: Saftey glasses should beworn during this procedure.

MAIN ASSEMBLY

23

24

5. Place second stage carrier assem-bly(2), with spline connections down,into hub(1G) so that the carrier’sspline connections mesh with thespline connections on output shaft(1A).

6. Spray oil on all exposed surfacesinside hub(1G).

7. Grease “O” ring(5).

8. Place “O” ring(5) into thecounterbore of hub(1G). Make surethat the counterbore is oil freebefore installing “O” ring.

CAUTION: Beware of sharp edges andburrs in the counterbore while in-stalling the “O” ring.

NOTE: “O” rings may be stretched to fit the counterbore. If an“O” ring has been stretched too much, simply squeeze the “O” ringtogether bit by bit as you place it around the counterbore. Itcan be made to fit exactly.

25

9. Spary oil on the inside of ringgear(4).

10. Place ring gear(4) with smalldiameter end down, into hub(lG) sothat it fits over second stagecarrier assembly(2).

11. Place second stage sun gear(11),with large diameter end down, intomesh with the planet gears of thesecond stage carrier assembly(2).

l2. Place large thrust washer(14),thrust bearing(13), and large thrustwasher(12) in that order into thecounterbore of second stage carrierassembly(2).

NOTE: Notice that thrust washer(14)is much thicker than thrustwasher(12).

13. Place thrust bearing carrier(10), with small diameter end down,into the counterbore of second stagecarrier assembly(2). It should fitover the thrust bearing set(12, 13,14) described in step 12.

26

14. Place first stage carrierassembly(3), with spline connectionsdown, into mesh with the secondstage sun gear(ll) and the ringgear(4).

15. Place small thrust washer(9) ontop of second stage sun gear(ll).

16. Place input gear(8), with smalldiameter end down, into mesh withthe planet gears of first stagecarrier assembly(3). The input gearshould be centered on the smallthrust washer(9).

18. Grease one side of large thrustwasher(12), thrust bearing(13), andlarge thrust washer(14) and placethem greased side down in that orderover the raised inside circular edgeof cover(6).

NOTE: Notice that thrust washer(14)is much thicker that thrust washer(12).

17. Set cover(6) down on its small diameter end.

19. Grease small thrust washer(7)and place it in the counterbore ofthe center hole in cover(6).

20. Grease “O” ring(5) and place itaround the counterbore in cover(6).

CAUTION: Beware of sharp edges andstalling the “O” ring.

21. Place cover(6), with largediameter end down, on top of ringgear(4) so that the cover ’s pipeplug hole aligns with the magneticpipe plug hole in hub(lG) accordingto figure 2.

NOTE: “O” rings may be stretched to fit the counterbore. If an“O” ring has been stretched too much, simply squeeze the “O” ringtogether bit by bit as you place it around the counterbore. Itcan be made to fit exactly.

27

28

Pipe Plug Timing

This figure shows the most commonpipe plug timing for this series.Pipe plug timings may vary amongunits with different model numbers.Refer to an original assembly printfor your particular unit to deter-mine its correct pipe plug timing.

22. Place the 24 grade 8 bolts(16)into cover(6) and tighten.

23. Using a torque wrench, apply 35-45 ft.-lbs of torque to each grade8 bolt (16).

Figure 2.

29

24. Apply a light coat of “Never-Seize” to pipe plug(15).

25. Tighthen pipe plug(15) into thepipe plug hole in cover(6).

26. Roll test the unit in bothclockwise and counterclockwisedirections. Perform the same numberof turns in each direction as theratio of the unit. The ratio numberis the same as the last two digitsin the model number found on the IDtag of the unit.

27. Leak test the unit at a pressureof 5 psi for 2-3 minutes.

28. At this point the main assemblycomplete.

TOOLING

The following specialized tools are used in the assembly ofthis unit. The tool diagrams included in this manual are intendedfor the customer who may wish to have a tool made. All tools mustbe made from mild steel. All dimensions are given in inches.

OPTIONAL: In order to improve tool life, tools may be carborizedand hardened. If this is done, however, the tools must be groundon all surfaces labeled with a “G” on the tool diagram.

1. TOOL NO. T-130717BEARING CUP PRESSING FIXTURE for CUP(1E)

2. TOOL NO. T-156792BEARING CUP PRESSING FIXTURE for CUP(1C)

3. TOOL NO. T-158049BEARING CONE PRESSING FIXTURE for CONE(1D)

4. TOOL NO. T-146588BEARING CONE PRESSING FIXTURE for CONE(1F)

5. TOOL NO. T-156766AN-18 LOCKNUT WRENCH

6. TOOL NO. T-156799SEAL PRESSING FIXTURE

30

SCALE: 3/4 ONE PIECET-130717

BEARING CUP PRESSING FIXTUREfor CUP(1E)

31

T-156792SCALE: 3/4

BEARING CUP PRESSING FIXTUREfor CUP(1C)

32

T-158049SCALE: 3/4 ONE PIECE

BEARING CONE PRESSING FIXTUREfor CONE(1D)

33

T-146588SCALE: full ONE PIECE

BEARING CONE PRESSING FIXTUREfor CONE(1F)

34

T-156766SCALE: 2/3 ONE PIECE

AN-18 LOCKNUT WRENCHUSE 3/4 in. DRIVE SOCKET

35

T-156799 SCALE: 2/3

SEAL PRESSING FIXTURE

36

PARTS LIST

ITEM

hub-spindle sub-assemblyoutput shaftsealbearing cupbearing conebearing cupbearing conehubtanged washerlockwasherlocknutretaining ringpipe plugpipe plugmagnetic pipe plug

second stage carrier sub-assemblysecond stage carrierthrust washerneedle rollerspacerplanet shaftplanet geardowel pin

first stage carrier sub-assembly1 first stage carrierthrust washerneedle rollerdowel pinplanet shaftplanet gear

ring gear“O” ringcoverthrust washer

input gearthrust washer

QUANTITY DESCRIPTION

1A1B1C1D1E1F1G1H1J1K1L1M1N1P

2A2B2C2D2E2F2G

3A3B3C3D3E3F

37

11111111111211

1121083333

11257333

1

2

3

456789

1

1

1

121111

ITEM

thrust bearing carriersecond stage sun gearthrust washerthrust bearingthrust washerpipe plugboltdrive screwID plate

QUANTITY DESCRIPTION

101112131415161718

1122212441

38

CROSS-SECTIONAL VIEW of S6A

39

Gradall Industries, Inc.

GRADALL Product Support Information

Subject: Drive Belt Routing

Affected Model: All GRADALL Series III and Series IV Hydraulic Excavators

This informational bulletin shows the removal, replacement and routing of the Drive Belt for Series III and Series IV Gradall Hydraulic Excavators equipped with or without Air Conditioning units. The process of removing and replacing the Drive Belt is as follows:

1. Swing idler pulley down to release tension on drive belt (15mm socket needed). Remove drive belt.

2. Swing idler pulley back into original position. 3. Check condition of idler pulley and related components. Replace as needed. 4. Route the new drive belt in the order shown in the appropriate illustration below (do not

route drive belt over idler pulley at this time). 5. Swing idler pulley down and route drive belt over pulley. 6. Swing idler pulley back into original position and inspect drive belt for proper alignment

and routing.

Drive Belt routing order for machines not equipped with A/C option:

1 – Alternator 2 – Coolant Pump 3 – Crankshaft 4 – Idler Pulley

Gradall Industries, Inc.

GRADALL Product Support Information

Drive Belt routing order for machines equipped with A/C option (or when adding A/C option):

1 – Alternator 2 – Coolant Pump 3 – Guide Pulley 4 – Compressor 5 – Crankshaft 6 – Idler Pulley

406 Mill Avenue SW, New Philadelphia, Ohio 44663 Telephone 330.339.2211 Fax 330.339.8468 www.gradall.com

GRADALL Hydraulic Excavators use a telescopic boom which requires periodic adjustment and maintenance to ensure correct operation and performance. This service information has been released as a reminder of key maintenance and adjustments required for the telescope boom. For additional information, please refer to the Operation and Safety Manual and Service Manual provided with each machine.

Affected Units: All Series III, IV & V GRADALL Hydraulic Excavators. For GRADALL Industrial

Maintenance machines, please refer to Service Information 41200124.

Corrective Action: The GRADALL telescope boom moves in and out within the main boom on

rollers. The telescope cylinder is supported within the telescope boom by a spider with spider

pads during the boom in and out movement. The rollers and spider pads require maintenance

and adjustment for proper operation and performance. Failure to properly maintain the rollers and

spider pads may cause damage to the boom weldments, rollers, spider assembly and telescope

cylinder.

TO: GRADALL Excavator Service Managers AFFECTED MODEL: All Current Production GRADALL Excavators

SUBJECT: Boom Adjustments and Maintenance REVISION DATE: August 14, 2017 BULLETIN NUMBER: 41200123 - A

Main Boom

Telescope Boom (shown Retracted)

Main Boom Roller Bracket (Single Rollers Shown)

Telescope Boom

Telescope Boom Roller Bracket

Boom Bar (3 corners of the main boom)

Boom Pipe (3 corners of the telescope boom)

Typical GRADALL Excavator Boom Assembly


Eccentric shaft and lock plate

Main Boom

Front of main boom showing main boom rollers and telescope boom. Note the main boom has flat rollers at the 2 lower pipes and a concave roller at

the top pipe.

View of rear of telescope boom showing telescope boom rollers. All 3 rollers are flat rollers running on the flat bar of the main

boom.

Telescope Boom

Roller, eccentric shaft and lock plate shown.

Lock plate retains position of eccentric shaft after adjustment.

XL5000 Main Boom Roller Arrangement shown

Side rollers are singles, all others are double rollers

Lock plate and

retaining bolts

Eccentric Shaft

Single Roller - Side

Double Roller & Bracket Bottom & Top Locations


A typical GRADALL Hydraulic Excavator boom assembly is shown on the previous pages

highlighting the important parts involved with the boom rollers, bars, and pipes. A single roller

bracket is shown on the end of the main boom. XL5000 series machines (XL5100-IV & V,

XL5200-III & V, XL5300-III & V) use double rollers on the main boom roller bracket. Maintenance

and adjustment of the double rollers are simlar to the single rollers.

Roller maintenance and adjustment highlights are listed below. For additional information, please

refer to the Operation and Safety Manual and the Service Manual:

• Boom rollers should be greased every day or every 10 hours (whichever comes first)

• External boom pipe and bars must never be greased. This will cause sliding of the rollers

and damge to the rollers, boom bar, or boom pipe.

• Boom rollers should be replaced when the roller becomes loose on the roller bushing.

• Boom adjustment should be checked every 2 weeks or 100 hours. If noticeable

movement exists between the main and telescope boom, roller adjustment is required.

• Booms should be adjusted to allow the telescope boom to be centered within the main

boom. Adjustment to align the rollers in the center of the boom pipe or boom bar aligns

the 2 booms.

• Boom adjustment should always be made with the telescope boom fully extended.

• It may be necessary to adjust the main boom bottom rollers to “rotate” the telescope

boom for proper centering of the rear rollers on the main boom bars.

• At the end of the main boom, the top concave roller and side flat rollers must be centered

on the pipe. The bottom rollers may not be centered on the 2 bottom pipes.

• At the rear of the telescope boom, all 3 rollers should be tracking in the center of the main

boom bars.

• When adjusted correctly, the main boom side rollers will not be tight against the boom

pipe. With light side pressure on the telescope boom, the side roller(s) on the unloaded

side of the boom will turn free by hand.

• The roller at the rear of the telescope boom should also not be adjusted tight. With slight

down pressure on the telescope boom, the top roller should turn free by hand.

• Roller adjustment is achieved using eccentric shafts that rotate to adjust the roller. Lock

plates are used to hold the eccentric shaft in correct position. Always correctly torque the

lock plate hardware after adjustment.

• Lock plates have a square hole for a ratchet to be used to help rotate the lock plate and

eccentric shaft.

• Machines with less than 200 hours will require more boom adjustment due to normal

break in than machines with more than 200 hours.

• After any boom roller adjustment, the boom should be run slowly in and out and look for

tight spots. Tight spots will make a “popping” noise during operation. If tight spots are

found, the boom rollers must be readjusted to eliminate the tight spots.

Boom Cylinder Spider

Inside of the telescope boom, a “spider” is used to support the telescope cylinder during

operation. The spider is affixed to the rod end of the boom cylinder and rides on the telescope

boom pipes using spider pads in contact with the boom pipe. The spider does require

maintenance and inspection for wear to provide proper support for the telescope cylinder.


Spider maintenance and inspection highlights are listed below:

• Spider pads are to be lubricated every 10 hours or daily (whichever comes first) with

grease.

• Always verify spider pads are taking grease. If the spider pad does not take grease, the

spider pad should be disassembled and cleaned to determine why the spider pad does

not take grease.

• Spider pads that have not been properly lubricated will make a grinding or squealing

noise in the boom.

• Spider retainer nut should be checked to verify it is tight every 750 hours or 6 months

(whichever comes first). If the spider retainer nut is not kept correctly tightened, the

spider, telescope boom cylinder, and telescope boom will be damaged if the spider

comes off the telescope boom cylinder.

• The inside of the telescope boom should have any dirt or debris that has accumulated

removed to avoid damaging the spider pads.

• Spider pads should be checked for wear every 100 hours or 2 weeks (whichever comes

first). Running with worn spider pads can cause damage to the telescope boom cylinder.

See drawings below showing wear limit. When spider pads are worn, it is recommended

all spider pads and hardware be replaced at the same time.

• If “legs” of the spider plates are bent, the spider plates and pads must be replaced.

Spider Pad (6 per boom)

Spider Plate

Spider Retainer Torque to 55 ft/lb (75 nM)

Grease Fitting - 3


Boom Cylinder Spherical Bearing

A spherical bearing is attached to the end of the telescope boom cylinder rod. The spherical

bearing is attached to the telescope boom at the tool (bucket) cylinder bracket. The spherical

bearing is retained to the cylinder rod with a heavy nut that is tightened during cylinder assembly.

The cylinder rod and bearing are retained to the tool cylinder bracket.

3/16” (4.8 mm) chamfer

3/32” (2.4 mm) chamfer or less

Cross section of a new spider pad showing chamfer

Cross section of a used spider pad showing allowable wear on chamfer. If remaining chamfer is less than

shown, the spider pads must be replaced

Boom Telescope Cylinder Rod

Spherical Bearing

Heavy Hex Nut


Spherical bearing maintenance and adjustment highlights:

• Bearing should be greased every 10 hours or daily (whichever comes first)

• Bolts that retain the bearing should be checked every 750 hours or 6 months (whichever

comes first) for correct torque.

• If the boom begins to have a “banging’ noise when starting or stopping, check the

spherical bearing for looseness. If the bearing is loose, the bolts retaining the bearing

must be checked for correct torque, the nut retaining the bearing to the telescope boom

cylinder rod must be checked for correct torque, and the bearing should be checked for

looseness or damage.

• If the spherical bearing is worn, it must be replaced.

• Running the machine with a loose bearing can damage the tool cylinder bracket which

cannot be replaced in the boom.

Regular maintenance and adjustment of the boom does not require significant time or expense.

By properly maintaining the boom assembly, your customers will be able to receive the best

performance from their GRADALL boom.

Recommended Action: Provide this Service Information to your service technicians and

customer service personnel. This Service Information has been provided for information only. No

warranty repairs are authorized or expected to be done as a result of this Service Information.

Contacts: Should you have any questions or require further assitance concerning this bulletin,

please contact your GRADALL Regional Service Manager or the GRADALL Service Department

at 1-800-445-4752.

Telescope Boom

Tool Cylinder Mounting Bracket

Spherical Bearing Retainer Plates and Bolt

Spherical Bearing @ Boom Cylinder Rod End

Documents

INTRODUCTION - MyGradall.commygradall.com/pdf/service_manuals/80804003_Mechanical Adjustment.pdfINTRODUCTION This manual is a ... THE ROLL TEST The purpose of a roll test is to determine