Power Recirculating Ball Buick Roadmaster VIII

DESCRIPTION & OPERATION

Note. Some vehicles are equipped with Variable Effort Steering (VES) system, identified by a solenoid on power steering pump at pressure line outlet. For Fleetwood models, see STEERING SYSTEM - VARIABLE EFFORT article in STEERING section. For Caprice and Roadmaster models, see STEERING SYSTEM - VARIABLE EFFORT article in STEERING section.

STEERING GEAR

Saginaw steering gear assembly contains a recirculating ball system which acts as a rolling thread between worm shaft and rack piston. (Scheme 7) The steering gear housing contains a control valve that directs pump hydraulic pressure through rotary valve spool and body to either side of rack piston. Hydraulic pressure exerted on rack piston lessens mechanical force required to turn pitman shaft and steering linkage.

STEERING LINKAGE

Steering linkage connects steering gear to front wheels through pitman arm. Steering linkage consists of pitman arm, idler arm, relay rod and tie rods. (Scheme 1) Tie rod ends connect to relay rod by ball studs. Adjuster tubes between inner and outer tie rod ends are used to adjust toe. Some models have a shock absorber attached to relay rod.

Scheme 1

POWER STEERING PUMP

Saginaw pump is a constant displacement vane type pump with an integral fluid reservoir. When fluid pressure exceeds preset limits, an internal flow control pressure relief valve opens, allowing fluid to return to reservoir and the inlet side of the pump. (Scheme 4)

TESTING

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

1. Connect Power Steering Pressure Tester (J-5176-D) or Power Steering System Analyzer (J-25323-A) in pressure line between pump and steering gear. Open valve fully. Start and run engine until fluid reaches normal operating temperature.
2. Check fluid level; add fluid as necessary. With engine at operating temperature, pressure reading should be 80-125 psi (5.6-8.8 kg/cm 2 ). If pressure is more than 200 psi (14 kg/cm 2 ), inspect system for restrictions or faulty flow control valve. CAUTION: To prevent pump damage, DO NOT hold valve closed for more than 5 seconds.
3. Completely close valve for a few seconds, and then open it, recording highest pressure obtained when valve is closed. Do this 3 times. Each reading should be at least 1000 psi (70.3 kg/cm 2 ).
4. If pressures are within 50 psi (3.5 kg/cm 2 ) of each other, pump is okay. If pressures are high and not within 50 psi (3.5 kg/cm 2 ) of each other, flow control valve is sticking. Remove and clean control valve with crocus cloth. Flush system if dirty.
5. 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. See «POWER STEERING PUMP»(/buick/roadmaster/viii-1991-1996/remont/manual-power-steering/#power-recirculating-ball) under OVERHAUL.
6. 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 3), steering gear is leaking internally. Repair or replace steering gear.

CAPACITY

POWER STEERING FLUID CAPACITY

FLUID TYPE

When adding or changing fluid, use power steering fluid meeting GM specification 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 COLD mark on dipstick.
2. Turn wheels from side to side, without touching stops at either end. Add fluid as necessary to maintain 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. Ensure wheels are at center, straight ahead position. Lower vehicle. Continue to run engine for 2 to 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 BELT

BELT ADJUSTMENT SPECIFICATIONS

WORM BEARING PRELOAD

See WORM BEARING PRELOAD under OVERHAUL.

PITMAN SHAFT OVER-CENTER TURNING TORQUE

See PITMAN SHAFT OVER-CENTER TURNING TORQUE under OVERHAUL.

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

Removal & Installation

Remove drive belt. To ease removal of pump from some vehicles, remove power steering pump pulley. Disconnect pressure and return hoses from pump. Remove pump mounting bolts. Remove pump. To install, reverse removal procedure. Fill and bleed hydraulic system. See HYDRAULIC SYSTEM BLEEDING under LUBRICATION.

POWER STEERING PUMP COMPONENTS

Removal & Installation (Pulley)

Remove drive belt. If necessary, remove pump for clearance. 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).

Removal & Installation (Drive Shaft Seal)

Remove pump and pulley. 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 in to place until it bottoms on shoulder.

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

Removal & Installation (Flow Control Valve)

Disconnect pressure line from pump. If necessary, remove pump for clearance. On vehicles with Electronic Variable Orifice (EVO), remove EVO actuator and pressure line adaptor. On vehicles without EVO, remove union bolt (line fitting). (Scheme 4) On all vehicles, remove flow control valve, "O" ring and spring. To install, reverse removal procedure using NEW lubricated "O" ring.

Removal & Installation (Reservoir)

1. Drain reservoir. Remove pulley and mounting brackets (if still on pump). Clean exterior of pump. Clamp pump housing in a soft-jawed vise.
2. On vehicles with EVO, remove EVO actuator and discharge fitting. On vehicles without EVO, remove union bolt. (Scheme 4) Remove reservoir-to-pump mounting studs at rear of pump. Using a soft mallet, tap on filler neck of reservoir. Move reservoir back and forth until free of pump.
3. To install, reverse removal procedure using NEW lubricated "O" rings. Ensure reservoir is seated properly. Fill and bleed system. See «HYDRAULIC SYSTEM BLEEDING»(/buick/roadmaster/viii-1991-1996/remont/manual-power-steering/#power-recirculating-ball__hydraulic-system-bleeding) under LUBRICATION.

INNER & OUTER TIE ROD ENDS

Note. Count the number of turns required to remove the inner or outer tie rod end from the tie rod adjuster tube for reassembly reference.

Removal

Raise and support vehicle. Remove cotter pins and outer tie rod end nuts. (Scheme 1) Remove inner tie rod end nuts. Using Universal Steering Linkage Puller (J-24319-01), remove outer tie rod ball studs from steering knuckle and inner tie rod ball studs from relay rod. Loosen adjuster tube clamp bolts and clamps. Unscrew and remove tie rod ends from adjuster tube.

Installation

1. Lubricate tie rod end threads with chassis lubricant before installing. Install inner and outer tie rod ends to adjuster tube, referencing the number of turns required when removing tie rod ends. Inner and outer tie rod end threads must be adjusted equally within 3 threads. Install adjuster clamps and clamp bolts. Ensure clamps are positioned between locating dimples on ends of adjuster tube.
2. Tie rod ends must rotate full travel and travel must be maintained during clamp tightening. Slot in adjuster tube and slot in clamp must be properly positioned. (Scheme 2)
3. Install inner tie rod ends to relay rod ensuring seal is on ball stud. Tighten Steering Linkage Installer (J-29193) to 15 ft. lbs. (20 N.m) to seat tapers. Install and tighten inner tie rod end-to-relay rod nuts to specification. See «TORQUE SPECIFICATIONS»(/buick/roadmaster/viii-1991-1996/remont/manual-power-steering/#power-recirculating-ball__torque-specifications). CAUTION: When installing outer tie rod end nut, tighten nut to align cotter pin hole. DO NOT tighten nut more than an additional 1/6 turn to align cotter pin hole. DO NOT back off nut to insert cotter pin.
4. Install outer tie rod end to steering knuckle. Install and tighten outer tie rod end nut to specification. See «TORQUE SPECIFICATIONS»(/buick/roadmaster/viii-1991-1996/remont/manual-power-steering/#power-recirculating-ball__torque-specifications). Install cotter pin. Adjust toe-in. See «WHEEL ALIGNMENT SPECIFICATIONS & PROCEDURES»(/buick/roadmaster/viii-1991-1996/remont/wheel-alignment/#wheel-alignment-specifications-procedures) article in SUSPENSION.

Scheme 2

1. Raise and support vehicle. Remove inner tie rod end nuts. (Scheme 1) Using Universal Steering Linkage Puller (J-24319-01), remove inner tie rod ball studs from relay rod.
2. Remove nut securing pitman arm to relay rod. Using steering linkage puller, separate pitman arm from relay rod. Steering may have to be placed in Unlock position and turned to remove relay rod from pitman arm.
3. Remove steering shock absorber nut from relay rod (if equipped). Using steering linkage puller, remove steering shock absorber from relay rod (if equipped).
4. Remove nut securing idler arm to relay rod. Using steering linkage puller, remove idler arm from relay rod. Remove relay rod.

To install, reverse removal procedure. Ensure seals are on ball studs. Using Steering Linkage Installer (J-29193), seat all tapers to 15 ft. lbs. (20 N.m). Remove steering linkage installer. Tighten all nuts to specification. See TORQUE SPECIFICATIONS . Adjust toe-in. See the WHEEL ALIGNMENT SPECIFICATIONS & PROCEDURES article in SUSPENSION.

IDLER ARM

Note. Replace idler arm assembly if an up and down force of 25 ft. lbs. (110 N.m), applied at relay rod end of idler arm, produces a lash of more than 1/8" (3 mm).

Raise and support vehicle. Remove idler arm-to-frame nuts and bolts. (Scheme 1) Remove nut securing idler arm to relay rod. Using Steering Linkage Puller (J-24319-01), remove idler arm from relay rod. Remove idler arm.

Note. Idler arm must be properly located on it's threaded support so idler arm ball socket will be level with pitman arm ball socket. Idler arm support must be threaded into idler arm bushing until distance from center of lower mounting bolt is 2.281-2.407" (57.84-61.04 mm). (Scheme 3) The position of the idler arm must be adjusted before installation. After adjustment, idler arm support must be free to rotate 90 degrees in each direction.

To install, reverse removal procedure. Ensure seal is on idler arm ball stud. Using Steering Linkage Installer (J-29193), seat taper between idler arm and relay rod to 15 ft. lbs. (20 N.m). Install nut securing idler arm to relay rod and tighten to specification. See TORQUE SPECIFICATIONS . Install idler arm to frame. Tighten idler arm-to-frame bolts/nuts to specification. Adjust toe-in. See procedures in the WHEEL ALIGNMENT SPECIFICATIONS & PROCEDURES article in SUSPENSION.

Scheme 3

Raise and support vehicle. Remove nut securing pitman arm to relay rod. (Scheme 1) Using Steering Linkage Puller (J-24319-01), remove pitman arm from relay rod. Remove pitman arm nut and washer. Mark relationship of pitman arm-to-pitman shaft. Using Pitman Arm Puller (J-9172 or J-6632-01), remove pitman arm.

Install pitman arm onto pitman shaft and ensure pitman arm-to-pitman shaft reference marks are aligned. Install NEW nut and washer and tighten to specification. See TORQUE SPECIFICATIONS . Ensure seal is on relay rod ball stud. Install relay rod to pitman arm. Using Steering Linkage Installer (J-29193), seat taper between pitman arm and relay rod to 15 ft. lbs. (20 N.m). Install and tighten nut securing pitman arm to relay rod to specification.

Note. If steering gear is to be overhauled, remove pitman shaft seals before removing steering gear. See PITMAN SHAFT SEALS .

1. Disconnect pressure and return lines from steering gear. Remove intermediate steering shaft lower coupling pinch bolt. Separate intermediate steering shaft lower coupling from steering gear stub shaft. Remove pitman arm nut and washer.
2. Using appropriate puller, separate pitman arm from steering gear. Remove ABS modulator bracket nut from steering gear (if equipped). While supporting steering gear, remove steering gear bolts. Remove steering gear.
3. To install, reverse removal procedure. Ensure steering gear is aligned as straight as possible with intermediate shaft. Tighten nuts and bolts to specification. See «TORQUE SPECIFICATIONS»(/buick/roadmaster/viii-1991-1996/remont/manual-power-steering/#power-recirculating-ball__torque-specifications) .

1. Remove pitman arm nut and washer. Using appropriate puller, separate pitman arm from pitman shaft. Clean exposed end of pitman shaft and bottom end of steering gear housing. Place drain pan under pitman shaft. Using internal snap ring pliers, remove retaining ring.
2. On all vehicles, prepare to catch fluid and components that will be forced out under system pressure. Start engine. Turn wheels fully to left to force out washer and double lip seal. Stop engine.
3. If necessary, finish removing washer and double lip seal using a small tipped screwdriver or hooked scratch awl. DO NOT scratch housing bore or pitman shaft surfaces.
4. Replace pitman shaft if shaft seal surfaces are pitted or rough. Remove burrs from housing, if present.

Install single lip seal and washer. Coat double lip seal and washer with grease. Using Seal Installer (J-6219), install double lip seal and washer. Install retaining ring. Position pitman arm onto shaft. Install washer and nut. Tighten pitman arm nut to specification. See TORQUE SPECIFICATIONS . Fill and bleed system. See HYDRAULIC SYSTEM BLEEDING under LUBRICATION.

Scheme 4

Disassembly

1. Remove pulley, drive shaft seal, flow control valve and reservoir. See «POWER STEERING PUMP COMPONENTS»(/buick/roadmaster/viii-1991-1996/remont/manual-power-steering/#power-recirculating-ball__power-steering-pump-components) under REMOVAL & INSTALLATION. Remove end cover retainer ring. (Scheme 4) 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 cam 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 cam 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. Drive new shaft seal into bore using Shaft Oil Seal Installer (J-22670) until seal bottoms on shoulder. 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 5)
3. Slide rotor over splines with counterbore of rotor facing down. 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. Slide cam ring over rotor on dowel pins with arrow facing up. (Scheme 6) Install 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.
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 a punch, tap end of end cover retainer ring 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 housing. Carefully position reservoir on pump housing. Visually align mounting stud holes until studs can be started into threads.
8. Press reservoir down on pump to seat on pump housing. Install union bolt (or EVO actuator) into flow control valve bore and tighten to specification. See «TORQUE SPECIFICATIONS»(/buick/roadmaster/viii-1991-1996/remont/manual-power-steering/#power-recirculating-ball__torque-specifications). Install pump pulley.

Scheme 5

Scheme 6

Note. Before removing steering gear, remove pitman shaft seals. See PITMAN SHAFT SEALS under REMOVAL & INSTALLATION.

Scheme 7

1. Remove pitman shaft seals. See «PITMAN SHAFT SEALS»(/buick/roadmaster/viii-1991-1996/remont/manual-power-steering/#power-recirculating-ball) under REMOVAL & INSTALLATION. Mount steering gear in soft-jawed vise with pitman shaft pointing down.
2. Remove pitman shaft adjuster lock nut. (Scheme 7) Remove side cover bolts. Rotate stub shaft to center the gear. Remove side cover, gasket and pitman shaft as an assembly. Remove pitman shaft seal (single or double lip seal).
3. Unseat housing end plug retaining ring by inserting punch into housing access hole. Remove housing end plug and "O" ring seal.
4. Remove stub shaft adjuster lock nut, using punch against edge of slots. Using Spanner Wrench (J-7624), remove adjuster plug. Pry thrust washer bearing retainer from adjuster plug. Remove bearing spacer, races, thrust bearing, "O" ring and retaining ring.
5. Place adjuster plug on suitable support with outside face down. Using Adjuster Plug Bearing Remover and Installer (J-6221), drive needle bearing, dust seal and lip seal from adjuster plug.
6. Remove stub shaft and valve as an assembly. Tap stub shaft lightly on wooden block to loosen shaft cap. Pull cap and valve 1/4" (6 mm) out from body. Disengage stub shaft pin from hole in valve spool. Pull and rotate valve spool to remove it from valve body. Remove valve spool "O" ring, valve body, Teflon rings and "O" ring seals. NOTE: DO NOT disassemble valve body. If valve body is defective, replace entire valve body as an assembly.
7. Turn stub shaft counterclockwise until rack piston begins to emerge from housing bore. Remove rack piston plug. Insert Rack Piston Arbor (J-21552) into rack piston. Hold arbor firmly against worm shaft while turning stub shaft counterclockwise to force rack piston from housing. Remove rack piston, balls and rack piston arbor.
8. Remove worm shaft, thrust bearing and races. Remove worm bearing and races. Remove arbor from rack piston. Remove balls, clamp, and ball guide. Remove Teflon ring and "O" ring seal. Using Internal Snap Ring Pliers (J-4245), remove pitman shaft seal retaining ring. CAUTION: DO NOT score housing bore or shaft surfaces when prying out shaft seals and washers.
9. Pry washer and double lip seal from housing. Pry out washer and single lip seal. Insert Pitman Shaft Bearing Remover and Installer (J-6278) through hole in top of housing. Drive out bearing. Carefully pry check valve from housing.

Clean housing and lubricate all internal components with power steering fluid. Replace steering gear housing if bore is damaged. Replace worn or damaged components.

Note. Lubricate all "O" rings and lip seals with power steering fluid before installation.

1. Drive check valve into housing, using a piece of tubing 4" (102 mm) long and 3/8" (9.5 mm) diameter. Coat pitman shaft double lip seal and washer with grease. Using Pitman Shaft Bearing Remover and Installer (J-6278), install needle bearing.
2. Using Pitman Shaft Oil Seal Installer (J-6219), install single lip seal, then washer. Install double lip seal and back-up washer. Using Internal Snap Ring Pliers (J-4245), install retaining ring. Install worm shaft "O" ring seal and Teflon ring. Fully seat worm shaft to rack piston. Align worm shaft groove with rack piston ball return guide hole. NOTE: Black balls are smaller than Silver balls. Black and Silver balls must be installed alternately into rack piston and ball guide to maintain preload.
3. Lubricate balls with power steering fluid. Insert balls into ball return guide holes while turning worm shaft counterclockwise. Install remaining balls into ball guide. Apply light grease to each end of ball guide to retain balls. Install ball guide and guide clamp. Tighten ball guide clamp screws.
4. Insert Rack Piston Arbor (J-21552) into rack piston bore while turning worm shaft counterclockwise. Install races and thrust bearing onto worm shaft. Insert worm shaft into housing.
5. Lubricate valve spool and "O" ring seal with power steering fluid. Assemble valve spool "O" ring seal and valve spool. Assemble valve spool and valve body by pushing and rotating until hole in valve spool for stub shaft pin is accessible from opposite end of valve body.
6. Assemble stub shaft and valve spool. Insert retaining pin. Ensure notch in stub shaft cap fully engages valve body pin and seats against valve body shoulder.
7. Assemble "O" ring seals, Teflon rings and valve body. Assemble stub shaft, valve assembly and worm shaft. Ensure pin on stub shaft aligns with slot in valve assembly. Install stub shaft and worm shaft into housing. Hold rack piston arbor tightly against worm shaft while turning stub shaft clockwise until rack piston seats on worm shaft. Install rack piston plug. Use Rack Piston Teflon Ring Compressor (J-8947) to compress seals.
8. Place stub shaft adjuster plug on suitable support with outside of plug facing up. Using Adjuster Plug Bearing Remover and Installer (J-6221), assemble stub shaft needle bearing and adjuster plug. Ensure identification mark on needle bearing faces remover and installer during installation. Using adjuster plug bearing remover and installer, assemble lip seal and dust seal. Install retaining ring.
9. Assemble "O" ring seal, large bearing race, thrust bearing, small bearing race, bearing spacer, thrust bearing retainer and adjuster plug. Install adjuster plug assembly into housing, using Spanner Wrench (J-7624). Take care not to cut seals when installing adjuster plug.
10. Install housing end plug "O" ring seal, end plug and retaining ring into housing. Ensure open end of retaining ring is about 1" (25 mm) from access hole in housing.
11. Screw pitman shaft into side cover until is fully seated. Install pitman shaft lock nut. Place gasket on side cover, bending gasket tabs around edge of side cover. Install pitman shaft and side cover into housing. Install and tighten cover bolts to specification. See «TORQUE SPECIFICATIONS»(/buick/roadmaster/viii-1991-1996/remont/manual-power-steering/#power-recirculating-ball__torque-specifications) .
12. Using Pitman Shaft Oil Seal Installer (J-6219), install pitman shaft seal(s), washers and retaining ring. Adjust steering gear. See «WORM BEARING PRELOAD»(/buick/roadmaster/viii-1991-1996/remont/manual-power-steering/#power-recirculating-ball) and «PITMAN SHAFT OVER-CENTER TURNING TORQUE»(/buick/roadmaster/viii-1991-1996/remont/manual-power-steering/#power-recirculating-ball) .

Note. This procedure adjusts amount of compression force exerted by the worm shaft on worm shaft conical bearing.

1. Remove steering gear. See STEERING GEAR under REMOVAL & INSTALLATION. Rotate stub shaft in both directions to drain fluid from steering gear. Using punch, remove adjuster plug lock nut from adjuster plug near stub shaft. (Scheme 7)
2. Using Spanner Wrench (J-7624), tighten adjuster plug until firmly seated in housing. This requires 22 ft. lbs. (30 N.m) of torque. (Scheme 8) Mark gear housing at a place opposite one hole in adjuster plug. Measure back (counterclockwise) 1/2" (13 mm) from first mark, and then make another mark on housing.
3. Turn adjuster plug counterclockwise until hole in adjuster plug is aligned with second mark on housing. Hold adjuster plug to maintain alignment with index mark. Tighten adjuster plug lock nut securely.

Scheme 8

Note. Adjust worm bearing preload before performing this procedure. This procedure adjusts clearance between the rack piston and pitman shaft sector teeth.

1. Remove steering gear. See «STEERING GEAR»(/buick/roadmaster/viii-1991-1996/remont/manual-power-steering/#power-recirculating-ball) under REMOVAL & INSTALLATION. Rotate stub shaft in both directions to drain fluid from steering gear. Loosen pitman shaft adjuster lock nut. (Scheme 7) Rotate pitman shaft adjuster screw counterclockwise until fully extended, and then turn clockwise one full turn.
2. Turn stub shaft from stop to stop, counting number of turns between stops. Beginning at either stop, turn shaft away from stop 1/2 the number of turns counted. This centers the gear. With gear centered, flat on stub shaft should face upward, parallel to side cover, and master spline on pitman shaft should align with adjuster screw.
3. Using an INCH lb. torque wrench with handle pointing upward, rotate stub shaft 45 degrees to each side of center to measure worm bearing preload torque. (Scheme 9) Record highest turning torque measured on or near center.
4. If turning torque measured is not 6-15 INCH lbs. (.7-1.7 N.m), turn pitman shaft adjuster screw clockwise until torque is as specified, and then add 6-10 INCH lbs. (.7-1.1 N.m) to this specification. While preventing adjuster screw from turning, tighten lock nut.

Scheme 9

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

See also:
• STEERING SYSTEM - VARIABLE EFFORT
• WHEEL ALIGNMENT SPECIFICATIONS & PROCEDURES
• POWER STEERING PUMP
• HYDRAULIC SYSTEM BLEEDING
• TORQUE SPECIFICATIONS
• POWER STEERING PUMP COMPONENTS