Power Steering Gear: Assembly
- Before assembling, all parts should be cleaned and well-oiled. Place worm needle bearing in bearing sleeve and check for excessive play. If necessary, use bearing with thicker needles: these are available in four gradations of 0.0008" (0.002 mm) each.
- Clamp valve housing in padded vise with large hole upward. Place preassembled worm in housing. Fit needle bearing, washer, and cover to valve housing. Bolt valve housing to gear housing and check turning torque of worm: Wrap a cord around worm shaft, attach a pull-scale, and note reading when worm begins to turn. It should be 3.7-6.5 lbs. (17-30 kg).NOTE: Make this check without worm shaft sealing ring in place.
Preload is variable by replacing bearing washers with ones of different thicknesses. After correct preload has been obtained, remove valve housing.
- Place new "O" rings on three grooves of worm. Carefully fit packing rings on top of "O" rings, starting with inner one. Place "O" ring in groove of piston cover and apply packing of 0.067" (1.7 mm) to "O" ring. Apply marking color to contact surface of worm, insert and rotate worm. Lift out worm and check contact against packing. If full contact is not obtained, replace packing with that of greater thickness.
- Remove and clean the worm. Install all "O" rings on valve housing side of cover. Fit same number of shims as removed. Install inner "O" ring and packing in housing. Place bearing washer and bearing in cover. Attach small valve housing sealing ring on suitable installation tool (2863) and insert in housing. Secure with circlip.
- The preassembled cover and valve housing are attached to the worm, using the installation tool (2863). Screw cover and valve housing together with four nuts and bolts. Clamp piston in padded vise (horizontally) and check worm torque. Torque should now be 10-15 lbs. (48-75 kg). Release worm and bearing from valve housing.
- Clamp valve housing in padded vise. Slide piston sleeve onto worm. Insert worm far enough into piston bore so that 16 recirculating balls may be inserted from front piston bore while turning worm. Insert remaining seven balls in ball guide tube and install guide.
- Now check torque required to turn worm in piston. Correct reading on the pull-scale will be 5-10 lbs. (23-47 kg). If value is out of tolerance, replace all balls; they are available in five different dimensions.
- Place "O" ring and piston ring in recess on piston sleeve. Attach preassembled cover with bearing washer, bearing, ring nut, and sleeve on the worm (see illustration).
- Insert worm into piston while making sure all 23 balls are correctly installed. Place packing strip over ball guide. Assemble piston and piston sleeve (note replacement of set pin if it was removed), positioning sleeve recess on tooth side of piston.
CAUTION: When assembling, take care not to allow worm to come out of piston too far, or balls may fall into piston bore.
Pull out ring nut and lock it by punch-locking with a center-punch (see illustration).
- Clamp housing in padded vise (housing horizontal) and insert middle needle bearing washer in housing (this is for bearing which rides beneath sector teeth). Fit its adjacent sealing ring with lip upward: Install with suitable drift.
- Install large oiled "O" ring on piston-side flange of piston cover, then install all other remaining "O" rings in cover. Insert piston and worm assembly into gear housing. Install suitable spreader tool (2863) in valve housing end sealing ring (see illustration), install housing end bearing, spread sealing ring, and install valve housing to gear housing.
- Place piston teeth in center position by lining up mark on end of worm shaft with line on housing end cover. If sector shaft middle and lower needle bearing races have not been replaced, grease and install bearing needles into races.
- Tape splines on sector shaft (to protect seal during installation) and insert shaft in housing, aligning sector teeth at mid position with piston teeth. Turn sector shaft back and forth a few times to ensure proper mesh of the gears.
- Install adjuster screw, adjuster washer, and circlip in top of sector shaft. Check that adjuster screw free play in shaft does not exceed 0.002" (0.05 mm). An increase in washer thickness will take up excessive play.
- Install needles in upper sector shaft bearing race. Place "O" ring on top cover. Attach cover by turning out adjuster screw until cover is in position. Temporarily install adjuster screw lock nut. Screw in cover retaining bolts. Install protective seal over worm shaft splines. Attach sealing ring and circlip on bottom end of sector shaft.
- Rotate sector shaft to one stop, turn back 1/2 turn, attach a pull-scale and check required turning torque. Now return sector shaft to center position and turn in adjuster screw until a noticeable midpoint pressure is obtained. This should give a torque of 10-13 lbs. (4.5-6.2 kg) greater than that measured at the 1/2 turn from end stop, but no greater than 40 lbs. (18.5 kg). Hold adjuster screw in this position and tighten lock nut.