Part 2

33. Fit 87 90 727 Bracket, dial gauge with 87 92 194 Dial gauge kit in the available hole. Set the tip against the differential housing. Run the output shaft with a drill and 87 92 053 Driver until the value on the dial gauge has stabilized. Reset the dial gauge.

Warning: Watch your fingers when the gear wheel is moving.





34. Lift the differential using 87 91 337 Drive, measuring differential bearing torque and read the value on the dial gauge.

The correct shim thickness is: measured value plus the value from the table.








^ Thicker shims = increase preload
^ Thinner shims = reduce preload
^ Shims for the differential are available in sizes 0.10, 0.15, 0.30, 0.50 mm





35. Remove the dial gauge, stand and bearing support. Fit and lubricate the O-ring on the bearing support. Fit the bearing support with the measured shims.
Tighten the bearing support until a little bearing play remains so as not to affect bearing preload adjustment on the output shaft. The bearing support is tightened more later.
36. Turn the gearbox so that it is in the same position as it would be in the car, i.e. horizontal.





37. Fit an 8 mm fuel hose (approximately 100 mm long) between 87 91428 Driver and a hexagon socket (M10 with 1/2" fitting). Make sure there is no gear engaged.

Important: The torque wrench is extremely sensitive to impact, overloading and rough treatment.

38. Connect the torque wrench (graduated in Nm) and rotate the wrench clockwise several revolutions at even speed. Read off the average value while rotating, normally 0.10-0.30 Nm.
If the value is higher than 0.30 Nm or if it varies greatly during rotation then the baulk rings are braking or there is dirt or cuttings in the bearing. Dismantle the gearbox and find the cause. It may help to rotate the shaft mechanically to and fro under an axial load. The bearings must then be oiled.
39. Turn the gearbox back around.





40. Place the tip of the dial gauge on the shaft as illustrated. Fit 87 92 053 Driver to the output shaft and "run" the gearbox with the drilling machine to settle the bearing. Operate the drilling machine while pressing first for about 20 revolutions and then zero the dial. Operate the drilling machine while lifting it for another 20 revolutions and take a reading (or until the reading has become stable). Remove the tool. Note the axial play reading and then add the nominal value. Remove the dial gauge.

Warning: Watch your fingers when the gear wheel is moving.

41. Engage 5th gear by pushing down the synchromesh sleeve. Engage 1st gear.





42. Remove 87 92 053 Driver from the output shaft.





43. Fit 87 92 061 Millimeter wheel, 27 mm to the output shaft nut. Set the calculated value (measured + nominal, see example) on the scale of the tool (mm-wheel).
Mark one tooth of the gear wheel with felt tip pen or similar. Each graduation corresponds to 0.01 mm.





Example: Measured value 0.43 + 0.03 (nominal value, over 5,000 km) = 0.46 mm
Check the rolling torque on new bearings only





44. Tighten in 2-3 stages until the zero graduation (0) of the tool (mm-wheel) reaches the marked tooth. Measure the axial play again as described in steps 40 44 to ensure the correct preload. Remove the tool and sleeve.
If an old bearing has been fitted to the output shaft, lock the nut and proceed to step 51.
If a new lager has been fitted, do not lock the nut and continue with the next step.
45. Before taking a more precise measurement of the output shaft bearing preload, the following must be complied with:
Input shaft bearing (axial play 0.09 - 0.15 mm)
Differential, bearing support fitted but not tightened (axial clearance 0.10 - 0.20 mm)
All bearings oiled
46. Turn the gearbox so that it is in the same position as it would be in the car, i.e. horizontal. Disengage 1st gear and lift off the 5th synchromesh sleeve.





47. Place the torque wrench at the 5th gear nut output shaft. No gear must be engaged. Rotate the torque wrench several turns clockwise at an even speed. Read the average value from the display during rotation.
48. The reading should be 0.5 - 1.0 Nm.
Tighten the output shaft (5th and 1st engaged) two graduations on the millimeter marking of 87 92 061 Millimeter wheel, 27 mm at a time until the correct rolling torque (0.5 - 1.0 Nm) is obtained.
Average torque varies greatly:
Cause:
Retarding baulk rings, swarf or dirt in the bearings.
Action:
Dismantle the gearbox.
Average torque higher than 1.0 Nm:
Cause:
Same as above or bearings too tight
Action:
Dismantle the gearbox and change clamping sleeve. The bearings should then be preloaded and checked.
49. Lock the nut on the output shaft.
50. Turn the gearbox back around.
51. Lift off the 5th synchromesh sleeve and fit the 5th fork to the 5th synchromesh sleeve. Fit the fork and sleeve to the shaft.
The 6 stop lugs on the synchromesh sleeve must mesh with the 6 deep tooth gaps in the synchromesh hub.

Important: The sleeve may only be put on the synchromesh hub where the high lugs on the sleeve are, in front of the tooth gaps in the synchromesh hub that is in between the deep tooth gaps as shown in the illustration.





52. Tap the retention pin into the selector shaft.
53. Fit a new circlip.
54. Tighten the screws for the differential bearing support.
Tightening torque 24 Nm (18 ft. lbs.)
55. Fit the gear cable bracket.
56. Put on a new gasket and fit the end cover.
Tightening torque 24 Nm (18 ft. lbs.)





57. Refit the reversing light switch with 74 96 284 Thread locking adhesive if it has been removed. Clean the reversing light switch and gearbox threads with 30 02 599 Cleaning agent.
Tightening torque 24 Nm (18 ft. lbs.)
58. Check that the magnet is in position in the oil drain plug. Fit the plug.
Tightening torque 50 Nm (37 ft. lbs.)
59. Fill with oil only after the drive shafts have been fitted to the gearbox and the gearbox has been fitted into the car. Oil capacity 1.9 Liters, refer to Summary of lubricants and sealants.
60. Lubricate the sealing rings on the slave cylinder.
61. Fit the slave cylinder, use 74 96 284 Thread locking adhesive on the bolts.
Tightening torque 10 Nm (7 ft. lbs.)





62. Fit the delivery pipe to the slave cylinder and fit the bushings.
63. Bleed the slave cylinder before fitting the gearbox. Refer to Bleeding the slave cylinder.
64. Remove the gearbox from the stand.