Note. It is recommended to replace the o-rings every time the steering mechanism is disassembled, even if they appear to be in good condition. Before installing the rings, carefully clean the grooves intended for them.
Select the thickness of the adjusting rings 6 installed in the intermediate cover so that the sealing edge of the grooved ring 3 has a slight preload.
Check the tension of the Teflon ring 5 of the intermediate cover. Install the thrust washer and thrust needle bearing in the intermediate cover. Install O-ring 1 and Teflon ring 2. Size «A» (see photo) Teflon ring should be 1.7 mm.
Remove and save gaskets, adjusting and adjusting rings, thrust needle bearing.
Install the worm shaft without Teflon and O-rings and grooved rings on the valve box without a gasket. Install the ball bearing outer race, thrust needle bearing and thrust washer.
Fasten the valve box with the intermediate cover to the steering gear housing by tightening the fastening bolts crosswise with a torque of 3.1 kgf·m.
Check the friction torque of the worm shaft. If necessary, adjust it by selecting the thickness of the thrust washer.
Unscrew the bolts securing the intermediate cover, replace the O-ring, Teflon ring, thrust needle bearing and insert the worm shaft into the intermediate cover.
Install the BMW 7015 tool and measure the friction torque of the worm shaft in a vertical position (see photo). If it is less than normal, install a thicker Teflon ring.
Check the total friction torque of the worm shaft head with new Teflon rings 1-4 installed on the piston head, with o-ring, grooved ring, gland and shims.
Insert the worm shaft head into the valve box, secure this assembly to the steering gear housing and adjust the preload by placing shims under the slotted ring.
Note. Do not remove valve plungers 1 (see photo), since during repairs, their adjustment and correct installation in relation to the hydraulic unit is not possible.
Check adjustment dimension «A» (see photo) for the steering limit valve, which should be 107-0.20mm.
Adjust the stop screw 2 (see picture) so that the restrictor valve opens about 2 mm before it touches the stop.
Insert the worm shaft into the piston, maintaining the dimension «A» (see photo), equal to 6 mm, and insert 16 balls into the grooves of the shaft through the front hole, while inserting the worm inside the crankcase.
Insert seven balls into the ball circulation guide tube, securing the last two balls with bearing grease.
Secure the top half of the ball circulation guide tube with the retaining spring.
Using tool 7015, check the friction torque of the worm shaft with the balls installed. At the same time, unscrew the worm shaft no more than 3.5 turns to prevent the balls from falling out.
Replace the remaining parts of the steering mechanism in the reverse order of disassembly, and install it in place.
From model year 1978, the installation of the steering gear housing is subject to the following:
- Set the steering wheel and wheels to the straight ahead position. In this case, the marks on the crankcase of the steering mechanism and the steering shaft must match;
- make sure that the steering shaft flexible coupling mounting bolt is located in the shaft lock groove. Lock the bolt with a cotter pin.