Land Rover/Range Rover Service Bulletin 8/86
From: Marit & Bjornung (bjjen13b@telepost.no)
Subject: Range Rover front propshaft
Date: Sun, 26 Nov 1995 21:50:51 +-100
To: Land-Rover-Owner@uk.stratus.com
Item 527
RR 86 MY
51/54 VIBRATION DIAGNOSIS
The following is intended as an aid for the diagnosis and solution of
vibration problems on 1986 model year Range Rovers.
When investigating complaints of vibration in the vehicle, it is important
that the vehicle is assessed in a logical manner, so that, by a process of
elimination, it is possible to determine the exact source of the problem.
Therefore the first part of this bulletin gives a step by step sequence for
the diagnosis of vibration sources and their elimination. Before initiating
any investigation, however, check the vehicle to ensure that the cause is
not due to an obviously simple fault. For example: check that all engine
and gearbox mountings are of the correct specification and are correctly
fitted; check that all exhaust mountings are correctly fitted, in
particular check that there is no metal to metal contact between the
mountings and the body; check the torque of the propshaft drive flange
bolts, the universal joints for excessive play and transfer box and
differential bearings for excessive wear.
If your initial investigations do not identify a problem it will be
necessary to carry out the following procedure, which will involve some
testing of the vehicle.
NOTE
Should it be found at the outset that several vibrations are evident at
different road or engine speeds, each must be treated individually. It is
highly unlikely that the vibrations will be due to the same problem and
therefore each will require a separate cure.
Similarly, if a vehicle is found to be suffering from a particularly harsh
vibration, it may not be possible to detect other, less noticeable vibra
tions which may exist. However, once the primary vibration has been
eliminated, the secondary vibration, which again will only be evident at
different road or engine speeds, will then become prominent. Again each
vibration must be treated separately, allowing the causes to be isolated
and the necessary remedial action taken.
RANGE ROVER VIBRATION DIAGNOSIS PROCEDURE
1. Road test the vehicle. Does the problem always occur at the same road
speed irrespective of the gear selected? (SEE NOTE A).
YES: CHECK 2.
NO: Confirm that the problem occurs at the same engine RPM in all gears.
CHECK 21.
2. Does the problem occur at 30-50 mph (48-80 km/hr) in all the available
gears?
YES: Check that the front propshaft is correctly phased. The rear yoke
must lead the front yoke by two splines. Fit correctly if necessary and
re-test. If problem persists CHECK 3.
NO: CHECK 9.
3. Mark the drive flange and remove the front propshaft, engage the diff
lock and re-test. Has the vibration been eliminated?
YES: CHECK 4.
NO: Check balance of front and rear wheel and tyre assemblies, using
ON-CAR balancing equipment. Check that tyres have even wear
characteristics with no evidence of flat spots. If wheels and tyres OK
Check 19.
4. Check drive flanges (front output drive flange and front differential
pinion flange) for eccentricity and run-out. (SEE NOTE B). Do the flanges
conform to the tolerances?
YES: CHECK 7.
NO: CHECK 5.
5. Replace the flange(s). Recheck the eccentricity and run-out. Does the
flange(s) conform to tolerances?
YES: CHECK 6.
NO: Fit 2nd replacement flange. Recheck eccentricity and run-out. If
tolerances are still incorrect, the differential unit (or alternatively
the transfer box) is suspect and should be checked separately. If
tolerances correct CHECK 6.
6. Re-test the vehicle with the front propshaft fitted. Is problem still
evident?
YES: CHECK 7.
NO: ------.
7. Substitute a replacement propshaft from a donor vehicle and Re-test. Is the problem still evident?
YES: CHECK 8.
NO: Replace propshaft with new unit (or leave on donor unit).
8. Fit the vibration damper assembly to the front axle, (see Attachment 1).
(The attachment contains some figures. For further information, please
contact Internet E-mail address: bjjen13b@telepost.no).Refit the front
propshaft and road test. Is the problem still evident?
YES: Repeat diagnosis.
NO: ------.
9. Does the problem occur at 80-80 mph (112-129 kph) in ALL the available
gears?
YES: Check that the rear propshaft is correctly fitted. The front and
rear yokes must be IN LINE. There should be no phase
difference. Realign if necessary and re-test. If problem persists,
check ALL wheel and tyre assemblies for balance. If problem still
evident CHECK 10.
NO: CHECK 19.
10. Mark the drive flanges and remove the rear propshaft. Secure the
transmission brake drum with the propshaft flange nuts. With the
differential lock engaged, re-test the vehicle. Is the problem still
evident?
YES: CHECK 11.
NO: CHECK 15.
11. Remove the transmission brake drum and re-test. Is the problem still
evident?
YES: Cause of problem is unknown. Re-check diagnostic procedure.
NO: CHECK 12.
12. Check the rear output flange on the transfer box, where the DRUM SITS,
for eccentricity and run-out (See NOTE B). Does the flange conform to the
tolerances?
YES: The handbrake drum is suspect and must be replaced with a known
good component. Then CHECK 15.
NO: CHECK 13.
13. Replace the output flange and recheck the eccentricity and run-out.
Does the flange conform to the tolerances?
YES: CHECK 14.
NO: Fit 2nd replacement output flange. Recheck eccentricity and run-out.
If tolerances still incorrect, transfer box is suspect, and should be
checked separately. If tolerances correct CHECK 14.
14. Refit the original handbrake drum and secure to flange with propshaft
nuts. Re-test the vehicle without the propshaft fitted. Is problem still
evident?
YES: The handbrake drum is suspect and must be replaced with a known
good component. Then CHECK 15.
NO: CHECK 15.
15. Check the rear differential pinion flange for eccentricity and run-out. (See NOTE B). Does the flange conform to the tolerances?
YES: CHECK 17.
NO: CHECK 16.
16. Replace the flange. Recheck the eccentricity and run-out. Does the
flange conform to the tolerances?
YES: CHECK 17.
NO: Fit 2nd replacement flange. Recheck eccentricity and run-out. If
tolerances are still incorrect, the differential unit is suspect, and
should be checked separately. If tolerances correct CHECK 17.
17. Re-test vehicle with rear propshaft fitted. Is problem still evident?
YES: CHECK 18.
NO: ------.
18. Substitute a replacement propshaft from donor vehicle and re-test. Is
the problem still evident?
YES: CHECK 20.
NO: Cause of problem is unknown. Recheck fault diagnosis procedure.
19. If the vehicle has a manual gearbox, does the problem occur at 30-50
mph (48-80 kph) in all the available gears except 4th gear.
YES: CHECK 20.
NO: Cause of problem is unknown. Recheck fault diagnosis procedure.
20. Disconnect the front propshaft. Re-test with the differential lock
engaged. Is the vibration still evident or is it worse?
YES: If this is confirmed, main gearbox is suspect, and should be
investigated separately.
NO: RE-CHECK 2.
21. Are the correct engine mountings fitted? Current production usage:-
Part no 566222 (colour coded yellow spot) for front engine mountings. Part
No NRC 9154 (colour coded white spot) for rear engine mountings. (See also
Service Bulletin 11A/85, Item 1).
YES: CHECK 22.
NO: Fit new engine mountings and re-test. If problem persists CHECK 22.
22. Remove the water pump drive belt. Test the vehicle statically by
revving the engine in neutral. In order to avoid any overheating of the
engine, DO NOT prolong the test. Does the problem remain?
YES: CHECK 24.
NO: CHECK 23.
23. Replace the fan and viscous drive unit, by substitution with known
components from a donor vehicle. Refit the drive belt. Re-test the vehicle
statically. Is the problem still evident?
YES: Replace water pump.
NO: ------.
24. Replace the electronic control unit by substitution with a known unit
from a donor vehicle. Does the problem still exist?
YES: Cause of problem is unknown. Recheck fault diagnosis. If the vehicle
is an automatic, check torque converter balance (see Attachment 2).
(The attachment contains some figures.)
NO: ------.
Bjornung Jensen, bjjen13b@telepost.no