Power Steering Pump Chevrolet Caprice Impala SS

DESCRIPTION & OPERATION

Power steering pump is a constant displacement vane-type pump with a remote fluid reservoir. When fluid pressure exceeds preset limits, an internal flow control pressure relief valve opens, allowing fluid to return to reservoir and inlet side of pump. (Scheme 10)

Scheme 10

TROUBLE SHOOTING

Note. See the TROUBLE SHOOTING - BASIC PROCEDURES article in the GENERAL TROUBLE SHOOTING section.

TESTING

Note. Incorrect fluid level, belt tension, idle speed or damaged pump pulley can affect test results. Correct such conditions before testing power steering system.

1. On Fleetwood, connect Power Steering Pressure Tester (J-5176-D) or Power Steering System Analyzer (J-25323-A) in pressure line from pump. On Caprice, Impala SS and Roadmaster, remove intake duct. Remove brake control valve bracket bolts and reposition to access steering gear. Connect tester in pressure line from steering gear.
2. On all models, open valve fully. Start and run engine until fluid reaches normal operating temperature. Bleed power steering system. See «HYDRAULIC SYSTEM BLEEDING»(/chevrolet/caprice-impala-ss/1995-1996/remont/manual-power-steering/#power-steering-pump__hydraulic-system-bleeding) . Check fluid level. Add fluid as necessary.
3. With engine at operating temperature, pressure reading should be less than 150 psi (10.5 kg/cm 2 ). If pressure is more than 150 psi (10.5 kg/cm 2 ), inspect system for restrictions. Check for proper installation of check valve in steering gear for. CAUTION: To prevent pump damage, DO NOT hold valve closed for more than 5 seconds.
4. Completely close valve for less than 5 seconds and then open it, recording highest pressure obtained when valve is closed. Repeat procedure 2 more times. Each reading should be at least 1000 psi (70.3 kg/cm 2 ).
5. If readings are within 50 psi (3.5 kg/cm 2 ) of each other, pump is okay. If readings are high and not within 50 psi (3.5 kg/cm 2 ) of each other, flow control valve is sticking. Remove and clean flow control valve with crocus cloth. Flush system if dirty.
6. If pressure readings are less than 1000 psi (70.3 kg/cm 2 ), replace flow control valve, then repeat test. If pressure is still low after replacing flow control valve, replace rotor and vanes. Refer to the «POWER STEERING PUMP»(/chevrolet/caprice-impala-ss/1995-1996/remont/manual-power-steering/#power-steering-pump) procedures under OVERHAUL.
7. If pump meets specification, leave valve open. Turn steering wheel from stop to stop, recording highest pressure at each stop. If pressure at both stops is not equal to pressure recorded in step 4), steering gear is leaking internally. Repair or replace steering gear.

CAPACITY

Note. Information is not available from manufacturer.

FLUID TYPE

When adding or changing fluid, use power steering fluid meeting GM Specification No. 9985010. Use of improper fluid will cause hose, pump and seal damage, resulting in fluid leaks and/or failure to operate.

FLUID LEVEL CHECK

Fluid level is indicated by marks on reservoir dipstick. When fluid is at operating temperature, about 170°F (77°C), fluid level should be at FULL HOT mark. Fluid level should be at FULL COLD mark when fluid is cold, about 70°F (21°C).

HYDRAULIC SYSTEM BLEEDING

1. With engine off, raise and support vehicle with front wheels off ground and turned fully to left. Add power steering fluid to FULL COLD mark on dipstick. Leave cap off.
2. Turn wheels from side to side, without touching stops at either end. Add fluid, if necessary, to maintain level at FULL COLD mark. It may be necessary to repeat this step several times.
3. Start engine. With engine idling, recheck fluid level. Add fluid, if necessary, to bring level to FULL COLD mark. Install cap. Ensure wheels are at center, straight-ahead position. Lower vehicle. Continue to run engine for 2-3 minutes to eliminate air in system.
4. Road test vehicle. Check for leaks. Ensure fluid level is at FULL HOT mark when fluid is stabilized at operating temperature.

Power steering pump is driven by serpentine belt. Belt tension is maintained by automatic tensioner. No maintenance or adjustment is necessary. Check belt operating range, indicated by marks on tensioner. If belt is not within operating range, check for proper installation before replacing belt.

REMOVAL & INSTALLATION

Raise and support vehicle. Remove electrical connector. Remove pressure switch from steering gear inlet hose. Lubricate "O" ring and threads of switch with power steering fluid. Install and tighten pressure switch to 115 INCH lbs. (13 N.m). Install electrical connector. Fill and bleed the power steering hydraulic system. See the HYDRAULIC SYSTEM BLEEDING procedures under LUBRICATION.

Siphon fluid from reservoir. Place drain pan under reservoir, and remove hoses. With rocking motion, pull reservoir from A/C accumulator assembly bracket. To install, reverse removal procedure. Ensure reservoir is seated properly. Fill and bleed system. Refer to the HYDRAULIC SYSTEM BLEEDING procedures under LUBRICATION.

Note. It may be necessary to remove pump bracket with pump. Bracket mounting bolts may extend into water jacket.

1. Siphon fluid from power steering reservoir. Drain cooling system. On vehicles equipped with mechanical fan, Disconnect negative battery cable. Remove upper fan shroud. Remove fan and clutch assembly. Remove cooling fan pulley bracket (if necessary). Remove radiator outlet hose and pipe assembly.
2. On all models, remove heater hoses from water pump and alternator and power steering pump bracket. Remove drive belt. Disconnect fluid reservoir and pressure hoses from pump. Remove pump mounting bolts. Remove power steering pump pulley (if necessary). Remove pump. To install, reverse removal procedure. Fill and bleed hydraulic system. See «HYDRAULIC SYSTEM BLEEDING»(/chevrolet/caprice-impala-ss/1995-1996/remont/manual-power-steering/#power-steering-pump__hydraulic-system-bleeding) under LUBRICATION. Fill and bleed cooling system.

PUMP PULLEY

Remove drive belt. If necessary, remove pump for clearance. See POWER STEERING PUMP . Install Pulley Remover (J-25034-B) on pulley. Remove pulley from shaft by holding body of tool with wrench and turning bolt. To install, use Pulley Installer (J-25033-B). Draw pulley onto drive shaft until face of pulley hub is even with shaft. DO NOT use a press to install pulley. Install pump (if removed).

Remove pump and pulley. Refer to the POWER STEERING PUMP and PUMP PULLEY procedures. Protect pump shaft with shim stock. Using a chisel, cut and remove seal. To install, coat shaft seal with power steering fluid. Using Shaft Oil Seal Installer (J-22670), drive new seal until it bottoms on shoulder.

Note. DO NOT disassemble flow control valve. If valve is sticking, clean with crocus cloth or replace valve.

Remove Pump. See POWER STEERING PUMP. On vehicles with Variable Effort Steering (VES) system, remove VES actuator and pressure line adapter. On vehicles without VES, remove union bolt (flow control valve fitting). (Scheme 10) On all vehicles, remove flow control valve and spring. To install, reverse removal procedure using a new, lubricated "O" ring. Tighten fittings to specification. Refer to TORQUE SPECIFICATIONS.

Disassembly

1. Remove pulley, drive shaft seal and flow control valve. See the «PUMP PULLEY»(/chevrolet/caprice-impala-ss/1995-1996/remont/manual-power-steering/#power-steering-pump__pump-pulley) removal and installation procedures. Also refer to the «DRIVE SHAFT SEAL»(/chevrolet/caprice-impala-ss/1995-1996/remont/manual-power-steering/#power-steering-pump) procedures as well as the removal and installation procedures in «PUMP FLOW CONTROL VALVE»(/chevrolet/caprice-impala-ss/1995-1996/remont/manual-power-steering/#power-steering-pump) procedures under REMOVAL & INSTALLATION. Remove end cover retainer ring. (Scheme 10) Remove end cover and pressure plate spring. Check shaft for corrosion. If shaft is corroded, clean with crocus cloth to prevent damaging shaft bushing when tapping shaft out of housing.
2. Tap lightly on end of shaft with plastic mallet to remove pressure plate. Remove pump ring and vanes. Remove and disassemble shaft, rotor and thrust plate assembly. Remove "O" rings from housing.

Inspection

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

Reassembly

1. Lubricate all "O" rings and sealing areas with power steering fluid. Place pump housing on flat surface. Using Shaft Oil Seal Installer (J-22670), drive new shaft seal into bore. To prevent seal from being distorted, DO NOT use excessive force.
2. Clamp pump housing in vise with shaft down. Install end cover and pressure plate "O" rings in grooves in pump cavity. With drive shaft clamped (splined end up), install thrust plate on drive shaft with ported side up. (Scheme 11)
3. Slide rotor over splines, and install rotor lock ring. Insert both dowel pins in holes of pump cavity. Rotor must move freely on splines. Install drive shaft assembly into pump body, ensuring dowel pins are properly engaged in thrust plate.
4. Install vanes in rotor slots. Slide pump ring over rotor on dowel pins with arrows facing up. (Scheme 12) 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.
5. Place pressure plate spring into groove in pressure plate. Position end cover lip edge up over spring. Press end cover down below retainer ring groove with thumb. Install retainer ring. Ensure ring is seated in groove. Use care to avoid cocking end cover in bore or distorting assembly.
6. Install flow control valve in bore, with control valve spring and hex end of valve facing interior of bore. Using new "O" rings, install union bolt (or VES actuator) into flow control valve bore and tighten to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/caprice-impala-ss/1995-1996/remont/manual-power-steering/#power-steering-pump__torque-specifications). Install pump pulley.

Scheme 11

Scheme 12

TORQUE SPECIFICATIONS

POWER STEERING PUMP TORQUE SPECIFICATIONS

See also:
• TROUBLE SHOOTING - BASIC PROCEDURES
• COMPUTER RELEARN PROCEDURES
• HYDRAULIC SYSTEM BLEEDING
• POWER STEERING PUMP
• PUMP PULLEY
• TORQUE SPECIFICATIONS