Printed in Canada

Service Bulletin No.2790MODEL TYPE SECTION/GROUP DATE

SUBJECT

CONDITIONS

July 11, 2001102D/DL Series Coaches Product Improvement 4--Brakes and Air System

PURAGUARD FILTER AND AIR DRYER BYPASS

Parts may be purchased from MCI Service Parts, Louisville, Kentucky or from MCIService Parts, Newcastle, Ontario.

Description:Effective with unit number 53455, MCI has made design changes to the AD9 Bendix air dryer installation, adding a ballvalve and a PuraGuard filter.The PuraGuard filter functions as a filtration device for air entering the supply reservoir. The ball valve is used to bypassthe air dryer and PuraGuard filter in the event of an air line freeze---up. The bypass valve can be manually set by theoperator, restoring air supply and allowing the safe return of the coach to the garage.The emergency bypass valve is for short term use only, due to unprocessed air entering the supply reservoir.

102 D AND DL MODEL COACH CUSTOMERS CAN PURCHASE A NEW PURAGUARD FILTER AND AIR DRYERBYPASS ASSEMBLY AT A REDUCED PRICE, FOR SIX MONTHS FOLLOWING THE DATE ON THIS BULLETIN.CUSTOMERS WHO ARE INTERESTED IN PURCHASING A NEW PURAGUARD FILTER AND AIR DRYER BYPASSASSEMBLY SHOULD CONTACT MCI SERVICE PARTS IN LOUISVILLE, KENTUCKY OR NEWCASTLE, ONTARIO.REFER TO THE SERVICE BULLETIN NUMBER AT THE TOP OF THIS PAGE WHEN PLACING THE ORDER.PartsQty. New P/N Description1 4L-7-129 PuraGuard Bypass Retrofit Kit

Kit contents are:1 4L-19-210 PuraGuard bypass assembly2 19-1-1095 Capscrew, hex, 5/16---18 x 1 inch, SS1 19-10-1472 Elbow, male, 3/4 inch T, 1/2 inch MPT2 19-10-1495 Fitting, straight, 3/4 inch NT, 1/2 inch MPT2 19-10-1684 Elbow, 90 degree, 3/4 inch NT, 3/4 inch MPT1 19-10-2283 Fitting, 3/4 C tube, 1/2 inch MPT1 19-10-544 Tee fitting, 1/2 inch FPT8 19-11-258 Tyrap9 19-11-259 Tyrap3 19-12-27 Grommet, 7/8 inch ID.1 19-12-4 Grommet, 3/8 inch ID.2 19-2-198 Lockwasher, 5/16, SS4 19-2-62 Flatwasher, 5/16, SS2 19-3-314 Hexnut, 5/16---18, SS2.3 ft. 21-7305-5 Pipe insulation, 7/8 inch ID x 3/8 wall26 ft. 24-54-0011 Pipe, tube, 7/8 inch ID x 3/8 wall1 4L-10-16 Decal, air dryera/r 21-7203-2 Sealant1 7L-13-4038 Air Dryer Bypass Switch Kit

Kit contents are:2 19-1-632 Screw, #10---24 x 3 / 8 inch1 19-11-258 Tyrap1 19-11-322 Connector, water tight6 19-11-569 Tyrap2 19-2-48 Lock washer, #104 19-2-7 Washer, flat, #101 4L-19-211 Plate, switch, bypass valve1 7K-8-209 Switch1 7L-12-3281 Harness, Air Dryer Bypass1 7L-13-4067 Schematic, Air Dryer Bypass

Printed in Canada

PAGEDATE 2Service Bulletin No. 2790PartsQty. New P/N Description1 7L-14-0145 Electrical Installation Kit, Air Dryer Bypass

Kit contents are:1 7L-8-3658 Tell tale light, air dryer bypass1 3L-1-1573 Plug, snap--- in1 7L-12-3323 Harness10 19-11-569 Tyrap1 7L-14-0144 Schematic

Service Information:1. New parts will be available for service replacement.

Service Procedure:General notesRead this entire procedure before beginning work.Use Safe Shop Practices At All Times.

1. Turn the main battery disconnect switch to OFF.2. Open the LH, front side service compartment door. Pull the front bumper release handle to access the

spare tire compartment ( Figure 1 ). Carefully remove the spare tire to gain access to the spare tirecompartment.

Figure 1. Front bumper release handle.

CAUTION

Wheel and tire assemblies weigh morethan 100 pounds. Use caution if re-quired to handle the wheel and tireunits.

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PAGEDATE 3Service Bulletin No. 27903. On the rear wall of the spare tire compartment, use a pencil and tape measure to mark the center of the

three air line holes, 1.5 inches from the bottom of the angle ( Figure 2 ). Mark intersecting lines ensuring 2.0inches between the centers of the holes. Using a 1 1/4 ( 1.25 ) inch hole saw, cut three holes ( located on theback wall of the spare tire compartment ) at the intersection of the lines. Install grommets ( part number19---12---27 ) into the three holes.

angle

Figure 2.4. Open the front, side service door. Using a tape measure, mark a line 9.0 inches from the outer wall, and

13.0 inches from the floor, on the rear wall of the compartment. Position the PuraGuard bypass assembly( part number 4L---19---210 ) on the rear wall, with the RH bracket hole centered over the intersection of thetwo lines ( Figures 3, 4, and 5 ).

13 inches

9inches

Figure 3.5. Using the bracket of the PuraGuard bypass assembly as a template, mark two holes. Place the PuraGuard

bypass assembly aside and drill the two holes using a 11 / 32 inch diameter drill bit.

Note: Use a drill bit depth gauge to avoid damage to other components.

Printed in Canada

PAGEDATE 4Service Bulletin No. 27906. Mount the PuraGuard bypass assembly to the compartment wall using the two capscrews ( part number

19---1---1095 ), four flat washers ( part number 19---2---62 ), two lock washers ( part number 19---2---198 ),and the two hex nuts ( part number 19---3---314 ) ( Figure 4 ).

“ A “

“ B “ “ C “

position the RH brackethole over the intersectionof lines, that were madeat 9 inches from the outerwall and 13 inches fromthe floor

mounting holes forswitch plate installation

Figure 4. PuraGuard bypass assembly.7. Using a 5/8 inch drill bit, drill a hole through the floor ( approximately 2 1/4 inches from the back wall ) in line

with the drain tube. Install the grommet ( part number 19---12---4 ) into the hole. Position the drain tubethrough the grommet ( Figure 5 ).

8. Slide the switch plate ( part number 4L---19---211 ) over the valve handle. Install the switch plate to the valveusing the two screws ( part number 19---1---632 ), four flat washers ( part number 19---2---7 ) and twolockwashers ( part number 19---2---48 ) ( Figures 4 and 5 ).

Note: To ensure proper alignment between the valve and the switch plate, the flat washers( which function as shims ) must be installed between the switch plate and the valve.

handletyrappedto switchplate

switch

drain tube

decal2 1/4 inches (+/-- )

Figure 5.

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PAGEDATE 5Service Bulletin No. 27909. Raise the coach to the desired height. Position jackstands at the front and rear frame support points,

according to Figures 6 and 7, to ensure that the coach is securely supported before attempting workunderneath the coach.

Note: Refer to Section 3G / Jackstand Support Points, in the MCI 102D Series MaintenanceManual, for the basic rules, procedures and safety precautions that must be followed before acoach is to be lifted.

Figure 6. D Series -- Under Frame Jackstand Support Points ( Section 3G / Maintenance Manual )

View from underneath frame --- looking upward

Front ofCoach

Rear ofCoach

Roadside

Curbside

axles not shownfor clarity

D Series Coach

FrontBogieSupportBeam

RearBogieSupportBeam

Figure 7. DL Series -- Under Frame Jackstand Support Points ( Section 3G / Maintenance Manual )

View from top of floor --- looking downwardRoadside

Curbside

DL Series Coach

Front of Coach

axles not shownfor clarity

Side View of Lower Frame --- Curbside

Tag AxleBogieSupportBeam

Drive AxleBogieSupportBeam

FrontAxleBogieSupportBeam

Rear ofCoach

Printed in Canada

PAGEDATE 6Service Bulletin No. 279010. Locate the air line from the air dryer delivery port to the wet tank. Remove and discard the air line.11. Remove the insulation over the copper tube ( air dryer supply line ) ( Figure 8 ). Cut the copper tube, 3

inches below the tunnel floor.12. Remove the existing elbow at the supply port of the air dryer. Install the elbow ( part number 19---10---1684 )

at the supply port of the air dryer ( Figures 8 and 9 ).13. On a workbench, pre---assemble the two fittings ( part number 19---10---1495 ), the tee fitting ( part number

19---10---544 ), and the copper tube connector fitting ( part number 19---10---2283 ) ( Figure 8 ).

Note: Apply sealant ( part number 21--7203--2 ) to the threads, before assembly.

tee fitting( 19--10--544 )

fitting( 19--10--1495 )

copper tubeconnector( 19--10--2283 )

1 foot piece ofnylon tubecopper tube

insulation

fitting( 19--10--1495 )

Figure 8.14. Cut a 1 foot piece off of the nylon tube ( part number 24---54---0011 ). Install the tube into the bottom of the

tee assembly and connect the tube to the elbow, installed in Step 12. Connect the copper tube connectorto the copper line.

15. Cut the nylon tube ( part number 24---54---0011 ) into three pieces, 7 feet, 8 feet and 10 feet.16. Install the nylon tube ( 7 feet long ) from the tee connector to the PuraGuard assembly, at location “ A “

( Figures 9 and 12 ).17. Install the nylon tube ( 8 feet long ) from the delivery port of the air dryer to the PuraGuard assembly, at

location “ B “ ( Figures 9 and 12 ).

Printed in Canada

PAGEDATE 7Service Bulletin No. 2790

elbows19--10--1684

7 ft. length of tube connectsto location “ A “ on PuraGuardassembly from tee connector

8 ft. length of tube connects to location“ B “ on PuraGuard assembly from thedelivery port of the air dryer

tee assembly10 ft. length oftube connectsto Port “ C “from wet tank

Figure 9.18. Install the nylon tube ( 10 feet long ) from the delivery port of the PuraGuard assembly to the wet tank, at

location “ C “ ( Figure 10 ).

Figure 10.

Printed in Canada

PAGEDATE 8Service Bulletin No. 2790

19. In the spare tire compartment, secure the nylon tubes using tyraps ( part number 19---11---259 )( Figure 11 ).

Figure 11.20. Route the tubes up and around the fresh air intake. Using three tyraps ( part number 19---11---259 ), secure

the tubes to the existing harnesses and airlines ( Figure 12 ).

part number 19--11--259

A

B

C

fresh air intake

Figure 12.21. Install the insulation ( part number 21---7305---5 ) over the air dryer supply line and elbow ( Figure 8 ).22. Lower the coach to the ground.23. Open the LH front side service compartment door. Using a clean cloth and isopropyl alcohol, wipe clean

the area where the air dryer decal is to be applied ( Figures 5 and 12 ).

Note: Allow 10 minutes for isopropyl to flash off.

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PAGEDATE 9Service Bulletin No. 279024. Apply the PuraGuard bypass decal ( part number 4L---10---16 ), 3.50 inches from the outer wall and 5.00

inches from the floor ( Figures 5 and 12 ).25. Using an allen key, remove the four screws from the LH switch panel, in the drivers compartment.

Figure 13.Note: The harness ( part number 7L--12--3323 ) will be routed from the ADBP switch locatedin the front, side service compartment to the air dryer bypass telltale light installed in thedrivers instrument panel. One end of the harness will have routed up through the electricaljunction box to the drivers instrument panel. The other end of the harness will have to berouted down through the electrical junction box to the front, side service compartment.

Note: The air dryer bypass telltale light should be installed in one of two designatedlocations, either a blank plug in the LH switch panel or in the blank plug beside the windshieldwiper controls ( Figure 13 ). If the telltale is to be installed in the location beside thewindshield wiper controls, the existing snap-- in plug will have to be discarded and replacedwith the plug provided in the parts list.

26. Open the front junction box door, located on the roadside of the coach. Feed a fish wire up through theharness tunnel in the front junction box, leading up to the LH switch panel ( Figure 14 ).

Printed in Canada

PAGEDATE 10Service Bulletin No. 2790

Figure 14.Note: If the telltale is to be installed in the location beside the windshield wiper controls, thenthe instrument panel will have to be pulled forward to route the harness. Use an allen key toremove the eight screws from the instrument panel, to allow the panel to be pulled forward.

27. Route harness ( part number 7L---12---3323 ) from the electrical junction box so that:a. wire 55BP ( with #10 ring terminal ) is routed to Stud 55,b. wire 36BP ( with #10 ring terminal ) is routed to ground studs,c. wires ADBP and 55BP ( with fast---on terminals ) are routed up to the blank telltale location,d. wires 36 BP and ADBP ( with #8 ring terminal ) are routed down to ADBP switch.

28. Attach the end of the harness ( wires ADBP and 55BP ) to the fish wire, and pull the harness up into thedrivers compartment through the LH switch panel ( Figure 14 ).

29. Secure wires 55BP and ADBP ( using fast---on terminal ) to the telltale. Secure the telltale into plug.30. In the front side service compartment, remove the switch housing from the switch on the air dryer bypass

control lever, by removing the two screws on top of the switch. Feed the harness through the water tightconnector ( part number 19---11---322 ) and secure wires 36BP and ADBP ( using ring terminals ) to the NCand C contacts on the switch.

31. Re--- install the switch housing on the switch, using the two screws removed in Step 28. Tighten the watertight connector.

32. Install the switch ( part number 7K---8---209 ) to the switch plate, mounted on the valve assembly, using thetwo screws ( part number 19---1---720 ), two lockwashers ( part number 19---2---83 ) and two nuts ( partnumber 19---3---26 ) ( Figure 5 ).

33. Secure wire 55BP ( using ring terminal ) to Stud 55 ( Figure 14 ).34. Using tyraps ( part number 19---11---569 ), secure the harness every six to eight inches.35. Re--- install the LH switch panel.36. Turn the main battery disconnect switch to ON position.37. Turn the valve handle on the air dryer pass assembly to the “ bypassed “ position. Enter coach and verify

that the telltale is illuminated on the instrument panel.

Note: If the telltale is not illuminated, turn the main battery disconnect switch back to the OFFposition and verify installation.

38. Once installation is complete and verified, turn the valve handle back to the normal position.39. Secure the handle into position using a tyrap ( Figure 5 ).

Procedure complete.