Carrier Side Gears: Service and Repair
Replacing Differential Bevel Gears (Type M)
Final Drive Housing Removed
Removing final drive housing: operation included in "Replacing drive pinion with crown wheel", refer to 33 12 551 Press off pulse spider.
Installation:
Press fit pulse generator wheel with special tool 33 1 358 (union ring).
Remove ring gear (cold).
Caution: If bearings were replaced, do not install crown wheel until after friction torque has been determined, similar to replacing bearings on final drive housing, refer to 33 11 731.
Installation:
Clean tapped bores thoroughly (tapper).
Heat plate spring to maximum 100°C (thermo-chrome pin).
Mount ring gear with two locally manufactured staybolts for guiding.
Installation:
Install new screws with Loctite No. 270 and tighten down in sequence (l ... 10).
Tightening torque and torque angle, refer to Technical Data
Press out final drive shaft with special tool 33 1 470 (feed mandrel) from countersunk side.
A = Pressing out direction
E = Pressing in direction
Turn out differential bevel gears with drive flange.
Remove differential side gears with diaphragm springs and shims.
Install both differential side gears with diaphragm springs (1) and shims (2).
Curved surface of diaphragm springs (1) faces differential case.
Center differential side gears with the drive flange.
Install special tool 33 1 306 (pressure piece) on one side.
Screw in special tool 33 1 441 (threaded plate) with special tool 33 1 430 (spindle).
Tighten special tool bolt to spread differential side gears so far apart, that the drive flange can just barely be turned.
Install differential pinion gears exactly opposite each other.
Move differential gears to installed position by turning drive flange.
Remove special tools.
Procedure with Hydraulic Press:
Check that circlip (1) is in correct installed position.
Slide in feed mandrel from side without a circlip.
Place differential shaft with large opening on the feed mandrel and press in.
The pressing-in force will increase stronger, when the circlip has engaged.
Caution: Stop the pressing-in step as soon as the force increases danger of shearing off the circlip.
Do not push back the differential shaft after installation.
Measuring Preload of Diaphragm Springs:
Install special tool 33 1 441 (threaded plate) and special tool 33 1 431 (screw).
Tighten bolt by hand.
Secure dial gauge to final drive housing with special tool 33 1 420, 00 2 505 and 00 2 506.
Set dial gage on blocked shaft gear to zero with preload.
Tighten spindle until diaphragm springs are pressed flat.
Read dial gage.
Loosen spindle.
Turn shaft gear and measure again at several points.
To ensure that the plate spring is not block-preloaded, clearance of 0.03 ... 0. 1 mm must be available.
The lower value would be ideal.
Repeat measurements on opposite shaft gear.
Excessive Clearance:
Install thicker shim.
Insufficient Clearance:
Install thinner shim.
Shims (2) are available in gage steps of 0.05 mm.
The opposite end is determined in the same manner.
Install shims (2) of determined thickness and diaphragm springs (1).
Inside curved surfaces of diaphragm springs (1) face differential case.
Operation with special tool 00 8 500 (extractor fixture)
Check that circlip (1) is in correct installed position.
Slide in special tool 33 1 470 (feed mandrel) on the side without circlip.
Place differential gear shaft with large opening on special tool and press in until 1 to 2 cm of shaft is visible.
Fit special tool 00 8 500 (extractor fixture) to final drive basket.
Torque = 22 Nm
(threaded spindle diameters 18 mm and 20 mm)
Caution: Lubricate center on differential gear shaft with oil before application of the special tool.
Differential gear shaft must no longer be pushed back after installation.
Always ensure that the last quarter of the torque (from approximately 17 Nm) is tightened at a uniform speed (i.e. smoothly and evenly).
To measure preload of plate springs, install special tool 33 1 441 (threaded plate) and spindle.
Tighten spindle by hand.
Mount holder with dial gage.
Set dial gage to zero with preload.
Tighten spindle until diaphragm springs are pressed flat.
Read dial gage.
Loosen spindle.
Turn shaft gear and measure again at several points.
To ensure that the plate spring is not block-preloaded, clearance of 0.03 ... 0.10 mm must be available.
The lower value would be ideal.
Repeat measurements on opposite shaft gear.
Excessive Clearance:
Install thicker shim.
Insufficient Clearance:
Install thinner shim.
Shims (2) are available in gage steps of 0.05 mm.
The opposite end is determined in the same manner.
Install shims (2) of determined thickness and diaphragm springs (1).
Inside curved surfaces of diaphragm springs (1) face differential case.