Usage:
NOTE: The information supplied in this service letter may not be valid after the termination date of this program. Do not perform the work outlined in this Service Letter after the termination date without first contacting your Caterpillar product analyst.
NOTE: This Program can be administered either before or after a failure. In either case the decision whether to apply the Program is made by the dealer. When reporting the repair, use "PS8647" as the Part Number and "7755" as the Group Number. If administered before failure, use "56" as the Warranty Claim Description Code and use "T" as the SIMS Description Code. If administered after failure, use "96" as the Warranty Claim Description Code and use "Z" as the SIMS Description Code.
Termination Date
June 30, 1997Problem
External water and condensation may enter the cab and accumulate on the floor of certain D250E and D300E Articulated Trucks.
Affected Product
Model & Identification Number
D250E (5TN1-382)
D300E (7FN1-255)
Parts Needed
- 1 - 1352933 Gasket
Action Required
See the attached procedure.
Service Claim Allowances
NOTE: This is a 4-hour job.
Parts Disposition
Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.
Attach.
- (1-Rework Procedure)
Rework Procedure
1. Remove the 4 bolts which hold the unit cover, and remove the outer cover and fresh air filter.
2. Raise and secure the cab.
3. Release the tie wraps securing the coolant and refrigerant lines.
4. When removing the outercover mounting bracket mark its location so that it can be reassembled in the correct position.
5. Release the quick disconnect at the orifice tube.
6. Loosen the two hose clips that secure the accumulator and rotate the accumulator to provide excess hose at the HVAC unit.
NOTE: Use gloves when releasing the quick disconnect coupling.
7. Clamp the coolant hoses to the heater coil.
8. Remove the tie wrap from the chain link on the top cover and withdraw the capillary tube.
9. Remove the 14 bolts and washers from the top cover.
Reassembly Note: Torque bolts to 9 ± 3 lb-ft.
10. Remove the 2 bolts that secure the infill plate. Remove the infill plate.
NOTE: Care point: The coil fins are sharp and can cut skin.
Reassembly Note: Torque the 2 bolts to 9 ± 3 lb-ft.
11. Remove the 2 nuts and washers from the left hand end of the evaporator coil.
Reassembly Note: Torque the nuts to 32± 5 lb-ft.
12. Remove the nut and washer from the right hand end of the evaporator coil.
Reassembly Note: Torque the nut to 32 ± 5 lb-ft.
13. Carefully move the evaporator coil away from the cab to disengage the 3 studs and remove the coil with the refrigerant hoses attached.
NOTE: The coil fins are sharp and can cut skin.
14. Place the evaporator coil as shown. Do not damage the coil fins or contaminate the coil with dirt.
15. Release the hose clip from the lower heater coil connection and remove the coolant hose. Drain the coolant from the coil into a suitable container.
NOTE: Ensure the coolant is at low temperature to avoid skin burns.
16. Repeat Step 1 for the upper heater coil connection.
17. Remove the heater coil and store in such a manner that the coil fins will not be damaged or contaminated with dirt.
NOTE: The fins are sharp and can cut skin.
18. Disconnect the wiring harness at the HVAC unit.
19. Clamp the coolant hose below the water valve. Loosen the hose clip and disconnect the hose from the water valve.
20. Place a nylon strap around the HVAC unit. Remove the eight bolts and washers securing the unit to the cab. Lift the HVAC unit (Approximate weight is 34 kg or 75 lbs) away from the cab with appropriate lifting device.
21. Remove the existing mounting gasket from the HVAC unit.
22. Reinstall the HVAC unit to the cab using new 135-2933 Gasket. Connect the coolant hose to the water valve and connect the wiring harness.
23. Ensure the 4 transfer holes in the baffle plate are not blocked. Remove any obstructions.
24. Using room temperature vulcanizing silicone sealant (RTV) seal joints on the drain pan perimeter. Pay special attention to the joints under the coil support plate. Do not seal the baffle plate transfer holes (4 off) or the drain holes (2 off located under the coil support plates).
25. Seal the air discharge aperture to the cab ductwork along the lower edge and for 50 mm up each side.
26. Seal all around the blower outlet ducts.
27. The frame on which the HVAC unit mounts to the cab may only be skip welded to the cab skin. If so, apply RTV all around the frame.
28. Ensure all drain pan joints are sealed at both sides and that the tack weld under the front coil support plate is sealed. Also seal around the 2 drain tube locations. Do not allow sealant to block the drains.
29. Remove the recirculation filter from inside the cab, and seal the HVAC unit to the cab side wall through the recirculation aperture.
30. Allow the sealant to vulcanize for approximately 30 minutes.
31. Reassemble the unit. The reassembly procedure is the reverse of dismantling.
32. When the unit has been reassembled, seal the HVAC unit to the cab wall along the top edge and both sides. Ensure the seal bridges the unit gasket and forms a water tight joint between the cab and the unit.
33. Seal the top cover all around and down the gaps on both sides.
34. Complete the assembly process. Remove the coolant hose clamps. Reconnect the refrigerant line to the orifice tube and secure the accumulator. Lower and secure the cab.
35. Reconnect the tie wraps to secure the hoses in the original positions.
36. Inside the cab behind the seat, remove the three allen head screws securing the cover for the EPTC II box. Remove the cover.
37. Apply RTV all around on the rectangular multi-pin connector plate that is skip welded to the cab skin.
38. Install the cover.