Power Steering Gear Box: Disassembly
- Drain fluid from gear box. Loosen adjusting lock nut and remove. Remove side cover bolts and screw in the adjusting bolt 2 or 3 turns. With gear in neutral position, tap bottom of cross shaft with plastic hammer and remove. Do not damage cross shaft splines and oil seal.
- Mount valve housing in vise and remove housing lock nut with spanner wrench (MB990852). Hold rack piston stationary and remove valve housing and rack piston assembly. Do not hold housing with rack pointing down as rack may slide off housing.
- Place valve housing in vise and move rack piston up and down to check backlash between circulator balls and rack piston gutter. Turn the rack piston fully into the valve housing and loosen 2 turns to measure backlash. Service limit is .008" (.2 mm). If backlash exceeds limit, replace ball screw unit and rack piston as an assembly.
- Remove rack piston by turning counterclockwise. Do not lose 26 circulator balls (except 4WD Pickups). Remove "O" ring, seal ring, steel balls, circulators and circulator holder from rack piston (4WD Pickups use only "O" ring and seal ring). Do not disconnect end cap.
- Loosen top cover with spanner wrench (MB990853). Remove top cover and input worm shaft from valve housing. Remove thrust plates, needle roller bearings, seal rings and "O" rings from input worm unit and valve housing.
- Screw in adjuster bolt at tip of cross shaft and remove side cover. Do not lose 33 rollers of roller bearing. Remove "O" ring, needle bearing, adjusting bolt and adjusting plate. Do not remove seal at rear of needle bearing unless fluid leaks from threads of adjusting bolt.
- Do not remove bleeder plug unless necessary. Remove seal ring and "O" ring from valve housing. Remove bearing and oil seal from top cover. Remove oil seal and seal ring from gear box. Do not disassemble needle bearing.
NOTE:
Replace all "O" rings, seal rings and oil seals once they
have been removed. When replacing, lubricate with power
steering fluid before insertion.