M/T - Adjustment of Output Shaft Bearing Tension
CATEGORYTransmission
SECTION
4
PAGE
38
ISSUE
01/97-0731
CODE
471
Subject:
Adjustment of Bearing Tension
Application:
All New Style 900, All 9000 Models with Manual Transmission
A new, more precise method to set output shaft bearing tension has been developed. This increases the service life of the affected bearings. The method is based on measuring the output axle turning torque, using a torque meter in the range of 0-300Ncm. Measurement is made after normal setting of bearing tension, but before the nut is locked. See the Action below for the proper procedure to carry this out. The tools that are required to perform this work are listed below.
Cars Affected:
1994- 900 and 1985- 9000 Models equipped with manual transmission.
Parts:
Driver 87 91 428
Torque Meter 87 92 483
M8 hexagonal socket
with 1/2" attachment source locally
M8 fuel line (approx. 100 mm long) source locally
2 hose clamps for fuel line source locally
The first two items are available for ordering directly from Kent-Moore at 1-800-345-2233.
Action:
18. To adjust the bearing tension, see Service Manual Section 4:1 Manual gearbox.
19. The following must be done before taking measurements:
^ Input shaft bearing fitted (axial clearance 0.04-0.16 mm)
^ Differential fitted (axial clearance 0.05-0.20 mm)
^ All bearings oiled
^ The gearbox must be in the same position as in the car (horizontal)
20. Fit the hose between tool 87 91 428 and the hexagonal socket. Make sure that no gear is engaged.
21. Quickly rotate the input shaft back and forth. Measurement can start when the shaft moves freely.
Important
Torque meters are extremely sensitive to impact, overload or heavy handling. If you are in the slightest doubt about the setting of the torque meter, have it calibrated immediately.
22. Attach the torque meter and rotate it several turns clockwise with even speed. Take the average reading from the meter during rotation, normally 10-30Ncm.
23. If the reading is higher, or varies significantly during rotation, the synchromesh sleeves or dirt/particles are preventing free movement. Dismantle the gearbox and establish the cause.
It can sometimes help to mechanically rotate the shaft back and forth under load, but the bearings must be oiled afterwards.
24. Move the torque meter to the output shaft on the 5th gear nut. NOTE: 5th gear nut must not be engaged. Rotate the torque gauge several times clockwise with even speed Take the average reading from the gauge during rotation.
25. Subtract the average reading for the input shaft from the average reading for the output shaft. The calculated tension is a measure of the output shaft turning torque, normally 50-100 Ncm. Example: reading on the output shaft = 11ONcm and reading on input shaft = 30Ncm gives 110 - 30 = 80Ncm.
^ If average torque is higher, or if it varies significantly, the synchromesh sleeves or dirt particles can be preventing free movement. Dismantle the gearbox and establish the cause.
If you suspect that the bearings are too tight (over 100Ncm) the gearbox must be dismantled and the collet changed. See Service Manual 4:1 Manual gearbox. The bearings should then be tensioned and test readings should be repeated.
^ If the calculated value is less than 50Ncm, the bearings are too close. If this is the case, tighten the output shaft bearing further in small steps until the desired reading is achieved.