- Press cover in slightly to remove retaining ring. Remove cover, coil spring and "O" ring. Remove end plate and "O" ring, noting location of pin in one of the small holes in end plate.
Courtesy of BMW OF NORTH AMERICA, INC.
- Tilt the pump housing. Remove cam ring and rotor. Note that side of rotor with recessed hole faces drive shaft and that the rounded-off side of rotor faces cam ring. The cast-in half arrow indicates direction of rotor rotation.
- Remove end face plate and "O" ring. Remove input shaft, pulley, shaft seal, and snap ring from housing (if necessary). Remove circlip. Remove shaft. Press ball bearing off shaft.
- Using a mandrel, press bearing sleeve out of housing. Remove plug from pressure valve bore. Remove coil spring and valve piston. Note that threaded section on valve piston faces coil spring.
CAUTION:
DO NOT
alter length of coil spring or thickness of plug sealing ring.
- The valve tolerance group ("1" or "2") is stamped into housing adjacent to pressure valve bore. Valve barrel should be scribed with one or 2 marks (lines) matching group number stamped into housing.
NOTE:
If valve must be replaced, install valve of same tolerance group.
- Clean and inspect all parts. Clean restrictor insert in pump outlet passage. Valve piston may be disassembled for cleaning. A pressure valve is located inside valve piston (flow limit valve).
CAUTION:
When disassembling piston, do not clamp across sliding surfaces.
- Thickness of washers determines cut-in range of pressure valve. Maximum pump pressure should not be more than 10 percent below value stated on plate attached to pump.