ACE TSB:
No: 60/02/99/NAS
Ref:*Issue: 2*
Date: 06/25/99
Ace Noise and Vibration Reduction
AFFECTED VEHICLE RANGE:
DISCOVERY Series II (LT) All
* indicates updated information
SITUATION:
EXCESSIVE NOISE FROM ACE SYSTEM
A customer may complain of noise or vibration especially at low engine rpm. The ACE system may be the source of this disturbance. The noise may be more apparent during cornering, or when the system is cold.
RESOLUTION:
INSPECT ACE PIPEWORK FOR CLEARANCE
If any ACE pipework is crimped or damaged, or if it is in contact with any other part, carefully correct the interference allowing a minimum of 5-10 mm (0.200 - 0.400 inch) clearance. At no point should any ACE pipework cross or contact other piping or vehicle components except at specific mounting locations. It may also be necessary to remove, adjust and refit any locating clips (see diagram) so that the rubber isolator holes are not distorted by the pipe.
PARTS INFORMATION:
No Parts Required
WARRANTY CLAIMS:
60.60.89/29 Time 0.70 hrs.
Isolate ACE Plumbing To Reduce Noise
Fault Code: K
Normal warranty policy and procedures apply
REPAIR PROCEDURE:
PREPARATION
1. Place vehicle on flat level surface.
2. Verify that gear selector is in PARK, handbrake is engaged, and ignition is off.
INSPECTION
CAUTION: Corrections must be made by hand to avoid small kinks and radii, which could increase the noise/vibration problem.
NOTE: The pipes in this system are labeled A, B, P, and T at the valve block and on the lines by using plastic tags. Gentle correction of the pipes is permitted by hand in most areas except the black sleeved "A" and "B " pipes on the actuators. A clearance of 5 - 10 mm (0.200 - 0.400 inch) should be maintained around all pipework.
NOTE: Other factors that could influence ACE system operation include:
^ Small stones trapped between the valve block and the chassis
^ The fastening of other vehicle components to ACE pipework
^ Incorrect torque on ACE pump pulley bolts
1. Follow both the high pressure and return hoses from the ACE pump (Figure 1 Position 3) and reservoir down toward the front chassis cross-member.
2. Inspect for possible interference with power steering lines.
3. Correct routing by hand where necessary.
4.* Verify that the ACE pump return line is correctly positioned and secured by the pipe support bracket and clip (Figure 2, Ref. 1).
5. Inspect for possible interference between the left and right oil cooler tube ends and the inner fender area on either side (Figure 2, Ref. 2).
CAUTION: If adjustment of the cooler tube ends is necessary, exercise extreme care. Alter the direction of the tube gently and gradually, only as much as required.
6. If contact is determined, carefully position the oil cooler tube ends away from the inner fender area (Figure 2, Ref. 2).*
7. Verify that the rubber isolator holes in the locating 'P' clips are not distorted.
8. Adjust any locating clips affected by the pipe alignment.
9.* Verify that the negative battery cable eyelet is oriented as shown in Figure 3, Ref. 1.
10. Verify that the negative battery cable runs in a smooth arc over the ACE jump hoses not forcing them into the inner fender panel flange, as this can cause chafing.*
11. Raise the vehicle.
12. Inspect the flexible high-pressure hose below the lower crimp (Figure 1 Position 2) toward the rigid (green) section.
NOTE: Light contact between the sponge sleeving of the flexible hose, and the radiator cowl is permitted, however all hose crimp ends should be isolated.
13. Correct routing by hand where necessary.
14. Verify that the rubber isolator holes in the locating "P" clips have not been distorted.
15. Adjust any locating clips affected by the pipe reworking.
16. Inspect the two-way "P" clip (Figure 1 Position 4) for interference.
NOTE: It is acceptable if the protected hoses from the front actuator contact the plastic shield.
17. Remove the three screws supporting the plastic shield forward of the right front wheel well.
18. Move the plastic shield aside.
19. Check for interference at the right front corner of the chassis, either with the chassis itself, or with other vehicle components.
20. Verify that the ground cable is routed from the base of the shock tower, inboard of all four pipes, onto the inner fender.
21.* Verify that the main body to chassis wiring harness is not trapped between ACE pipes and the RF inner fender panel (Figure 4, Ref. 1).
22. If the harness is trapped, perform the following:
^ Manipulate the fender panel outward, 10 - 15 mm, to free the trapped harness.
^ Carefully feed down any slack in the harness from the engine bay.
^ Route the harness in a non-interfering path.*
23. Examine the integrity and configuration of the 4-way isolators (Figure 1, Positions 7 & 8).
24.* Adjust positions 4 and 8 isolator as follows (Figure 5):
^ Remove outer nut from cushion stud.
^ Slide isolator bracket off of outer cushion stud.
^ Slacken inner cushion stud and then torque to 7 Nm (62 lbf.in).
^ Install isolator bracket and nut.
^ Torque outer nut to 7 Nm (62 lbf.in).
^ Verify isolator "P" clip is not in contact with the chassis frame at the bottom of the clip.*
25. Check for interference at the diagonal sections of pipe on either side of the shock tower.
26. Verify that there is no transfer of ACE system vibration to the chassis through the electrical harness, or by contact with the inner tender.
27. Inspect the remaining length of pipe routing over the chassis outrigger (Figure 1), looking for direct contact with the chassis, body or wiring harness.
28. Correct routing manually where necessary.
29. Verify that the rubber isolator holes in the locating "P" clips (Figure 1 Position 9) have not been distorted.
30. Adjust any locating clips affected by the pipe reworking.
31. Inspect ACE tubing to the rear actuator for contact with the frame, electrical harnesses or other components.
32. Correct routing by hand for proper clearance as required.
TORQUE PUMP BOLTS
1. Loosen all three of the pump bolts (Figure 5, References A & B).
2. Torque upper pair of pump bolts to 25 Nm (18.5 lbf. ft.) (Figure 6, Reference A).
3. Torque single lower pump bolt to 25 Nm (18.5 lbf. ft.) (Figure 6, Reference B).
4. Loosen the three pulley securing bolts (Figure 7).
5. Torque each pulley bolt to 25 Nm (18.5 lbf. ft.).
6. Evaluate ACE system noise level.
