Power Steering Pump Buick Electra VI

DESCRIPTION

The Saginaw Vane power steering pump is a constant displacement, vane operated pump with an integral oval shaped fluid reservoir. A pressure hose and return line connect the pump to the steering gear.

Rectangular pumping vanes carried by a shaft driven rotor move the fluid from the intake to the cam ring pressure cavities. Centrifugal force positions the vanes against the inside surface of the cam ring. As the rotor turns, the vanes pick up residual fluid. Continued rotation of the rotor forces the fluid into a high pressure area.

As more fluid is picked up by the vanes, it is forced into the cavities of the thrust plate through 2 crossover holes in the cam ring and pressure plate. The crossover holes empty into the high pressure area between the pressure plate and the housing end cover.

When the high pressure area is filled, fluid flows is under the vanes, forcing them to follow the inside surface of the cam ring and effectively sealing pressure. As the vanes reach the restricted area of the cam ring, hydraulic pressure is produced.

When the pressure exceeds set limits, the flow control pressure relief valve opens and allows fluid to return to the inlet side of the pump. Under normal conditions the pressure relief and flow control valves are closed as the pressure requirements of the pump are below maximum.

TROUBLE SHOOTING

Refer to TROUBLE SHOOTING - BASIC PROCEDURES article in the GENERAL TROUBLE SHOOTING section.

LUBRICATION

For further information see POWER STEERING GENERAL SERVICING article in the STEERING section.

Removal

1. Place container under vehicle to catch any fluids lost during removal of pump. Disconnect hoses at pump or steering gear. Plug fittings to prevent contamination of system. Loosen belt tension and remove drive belt.
2. Remove pump mounting hardware, and remove pump. Depending on engine and air conditioning configuration, it may be necessary to remove additional components to gain access to pump and mountings. On some models, power steering pump pulley may be removed to ease removal of pump.

Note. It may be necessary to remove pump bracket along with pump on some models. If bracket bolts extend into water jacket, coolant should be caught in drain pan.

Installation

To install, reverse removal procedure.

1. Pump pulley is a press fit on shaft and must be removed and installed with puller tools. DO NOT hammer on puller, pulley or shaft, or possible damage to internal pump components may occur.
2. Clamp pump in vise at mounting bracket or front hub. Avoid clamping front hub too tightly with vise. Use pulley remover tool, ensuring that it is aligned with shaft, and remove pulley. Refer to the «PUMP PULLEY SERVICE TOOLS»(/buick/electra/vi-1985-1990/remont/manual-power-steering/#power-steering-pump) for correct removal and installation tools.

Place pulley on end of pump shaft and install removal and/or installation tool. Press pulley onto shaft until tool bottoms on shaft.

PUMP PULLEY SERVICE TOOLS

Removal & Installation

Remove power steering pump from vehicle, and remove pump pulley. Protect pump shaft with shim stock. Using a chisel, cut seal and remove. To install, coat shaft seal with power steering fluid. Using a 7/8" or 15/16" socket, drive new shaft seal in place until it bottoms on shoulder.

1. Remove pump from vehicle, and drain. Mount pump in vise with pump shaft facing down and vise jaws contacting only the pump not the reservoir.
2. Remove 2 reservoir-to-pump mounting studs at rear of pump. Remove pressure line outlet fitting. Using a soft mallet tap on filler neck of reservoir, moving it back and forth until it is free of pump.

1. Prior to installation lubricate and replace pump housing "O" ring, 2 pump-to-reservoir stud "O" rings and outlet fitting "O" ring. Slide reservoir over pump and ensure that it is seated properly.
2. Install pump-to-reservoir mounting studs, and tighten to 26 ft. lbs. (35 N.m). Install outlet fitting and tighten to 55 ft. lbs (75 N.m). Install pump in vehicle, refill with power steering fluid, bleed system and check for leaks.

Scheme 1

1. Remove pulley as previously outlined and remove key from shaft. Remove brackets from pump, drain reservoir, and clean exterior of pump. Using a vise with soft jaws, clamp pump (shaft down) between square boss and shaft housing.
2. Remove pressure fitting and "O" ring seal. Remove retaining studs. Rock filler tube back and forth gently to loosen, and work reservoir off pump body. Discard all old "O" rings.
3. Using a punch, tap end cover retaining ring around until one end of ring is near hole in pump body. Insert punch in hole far enough to disengage ring from groove in pump bore and pry ring out of pump body.
4. Tap end cover with plastic hammer to jar it loose. Spring located under cover should push it up. Remove pump body from vise.
5. Place pump in inverted position on flat surface. Tap end of drive shaft with plastic hammer to loosen pressure plate, rotor, and thrust plate assembly from body. Lift pump body off rotor assembly.
6. Flow control valve and spring should slide out of bore. Remove and discard end plate and pressure plate "O" rings. Remove drive shaft oil seal. (Scheme 1): Exploded View of Flow Control Valve
7. Inspect seal bore in housing for burrs, nicks or score marks that would allow oil to by-pass outer seal surface. Lift pressure plate and cam ring from rotor. Remove 10 vanes from slots. Clamp drive shaft in soft-jawed vise with rotor and thrust plate up.
8. Remove rotor lock ring by prying off with screwdriver and discard. Use care to avoid nicking rotor end face. Slide rotor and thrust plate off shaft. Remove shaft from vise.

Note. Flow control valve is serviced as an assembly and should not be disassembled. However, if pump is being overhauled because of dirt in system, valve can be disassembled for cleaning.

Cleaning & Inspection

1. Clean all pump parts in solvent. Replace any damaged or worn parts. Inspect flow control valve for wear or damage. Inspect fit of vanes in rotor. Vanes must slide freely into slots of rotor without binding. Excessively loose vanes require replacement of rotor and/or vanes.
2. Examine inner surface of cam ring for heavy scuff or chatter marks and replace (if necessary). Inspect flat surfaces of pressure and thrust plates for wear or scoring. Light scoring can be removed by lapping on a flat surface.
3. Inspect pump body drive shaft bushing for excessive wear. Replace pump body and bushing as an assembly if badly worn or scored.

Note. If pump is equipped with self-attaching magnet, ensure that all particles are cleaned from magnet.

Scheme 2

Scheme 3

1. Lubricate all "O" ring seals and seal areas with power steering fluid. Place pump body on flat surface. Drive new pump shaft seal into bore with a 7/8" or 15/16" socket until seal bottoms on shoulder. DO NOT use excessive force as seal can be distorted.
2. Clamp pump body in vise with shaft down. Install end cover and pressure plate "O" rings in grooves in pump cavity. With drive shaft clamped, splined shaft up, install thrust plate on drive shaft with the ported side up. (Scheme 2) (Scheme 2): Installing Thrust Plate
3. Slide rotor over splines with the counterbore of rotor facing down, and install rotor lock ring. Insert both dowel pins in 2 holes of pump cavity. Rotor must move freely on splines. Install pump shaft assembly in pump body, ensuring that dowel pins are properly engaged in thrust plate.
4. Slide cam ring over rotor on dowel pins with arrow facing up. (Scheme 3) Install 10 vanes in rotor slots. Position pressure plate on dowel pins with plate spring groove facing upward. Place a 1 1/4" socket in groove of pressure plate. Seat entire assembly on "O" ring in pump cavity by pressing down with both thumbs. (Scheme 3): Installing Cam Ring
5. Place spring in groove in pressure plate and position end cover lip edge up over spring. Press end cover down below retaining ring groove with thumb. Install ring, making sure it is seated in groove. Care should be exerted to prevent cocking end cover in bore or distorting assembly. NOTE: If flow control valve was removed, install in pump bore with spring and hex end of valve facing interior of bore.
6. Using a punch, tap retainer ring ends around in groove until opening is opposite flow control valve bore. This is important for maximum retention of retainer ring.
7. Replace reservoir "O" ring seal, 2 mounting stud "O" ring seals and flow control valve "O" ring seal on pump body. Carefully position reservoir on pump body. Visually align mounting stud holes until studs can be started in threads.
8. Press reservoir down on pump to seat on pump body. Place new seal on pump union and install union in flow control valve bore. Tighten mounting studs and install pump pulley.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

See also:
• TROUBLE SHOOTING - BASIC PROCEDURES
• POWER STEERING GENERAL SERVICING
• PUMP PULLEY SERVICE TOOLS