Steering Wheel - Vibration on Rough Roads
14/01/9457/01/94/US
SUBJECT:
Steering Kickback (Vibration) Coil Spring Suspension With Sway Bar
MODEL:
Range Rover
AFFECTED VEHICLES:
All coil spring with sway bar derivatives from VIN LH 610295
DETAIL
Prolonged steering wheel vibration over uneven road surfaces, after crossing a ridge or travelling on a poor condition road surfaces. The resultant action of the steering is that initial sudden steering movement does not cease after the first disturbance but is gradually damped out over a series of steering wheel movements, typically four in quick succession. The steering wheel movement reduces in severity with each oscillation.
NOTE:
This Bulletin replaces the provious Bulletin P93/57-002
NOTE:
Radius arm bushes NTC 6860 were introduced coil spring vehicles at VIN LH 633740
NOTE:
Front and rear shock absorbers STC 241 and STC 242 were introduced onto coil spring vehicles at VIN LH 639407.
ACTION REQUIRED
In the event of customer concern carry out the procedure detailed following. Please submit a Product Report on vehicles that exhibit steering kickback after VIN LH 639407, (coil spring derivatives only).
PARTS INFORMATION
NTC 6860 Front radius arm bushes.
STC 241 Front shock absorbers.
STC 242 Rear shock absorbers.
RTC 6825 Harmonic damper kit.
WARRANTY
Normal warranty policy and procedure applies.
Claim Type: R
Fault Code: W
Front shock absorbers
Rear shock absorbers
COMP. CODE: N/A
SRO
Procedure 1 only
57.10.30 road test and checks 01.20 hours
Procedure 2 (includes PROCEDURE 1 time)
60.31.10 Road test, checks, fit harmonic damper and front and rear shock absorber kit.03.45 hours.
PROCEDURE
In the event of customer concern carry out the preliminary checks 1 to 7.
NOTE:
When replacing radius arm front bushes NTC 6781 with NTC 6860 the harmonic damper kit must also be fitted. (Note NTC 6860 have been fitted as standard on all coil spring vehicles since VIN LH 633740). If the vibration still exists on vehicles fitted with radius arm bushes NTC 6860, fit the shock absorber kits.
Note, these shock absorbers were fitted to vehicles at VIN LH 639407.
PROCEDURE 1 (Before any parts replacement)
1) Road test vehicle to confirm customers concerns.
2) Check tire condition and pressures.
3) Check all steering and front suspension fixing torque values. Refer to the Workshop Manual sections 57, 60, 64.
4) Check and adjust front wheel balance.
5) Check front hub end float. Refer to the Workshop Manual section 54.
6) Check and reset steering box on centre position.
7) Re-assess vehicle, if the original concern still exists proceed as follows:
PROCEDURE 2
8) Replace the front radius arm bushes NTC 6781 with NTC 6860.
9) Fit harmonic damper kit if required.
10) Fit front STC 241 and rear STC 242 shock absorbers.
11) If it is necessary to adjust front hub preloads refer to section 57 of the workshop manual.
NOTE:
Under no circumstances should the swivel pin preload be set higher than the recommended settings. Should the preload be set higher than that stated premature wear of the bearings will take place and steering feel will be affected. Refer to the Workshop Manual section 54.
Should steering kickback be evident after carrying out these checks, please submit a Product Report to Technical Service.