Steering Gear - Manual GMC Sonoma Syclone

DESCRIPTION & OPERATION

Steering gear is a recirculating ball-type consisting of a ball nut connected to steering worm and in-mesh with sector gear. Proper engagement between sector and ball nut is obtained by adjusting screw. Worm bearing adjuster can be turned to provide proper preloading of upper and lower bearings.

WORM BEARING PRELOAD

1. Place reference marks on pitman arm and sector shaft. Using Pitman Arm Remover (J-6632-01), remove pitman arm from sector shaft. Loosen worm bearing adjuster lock nut. Back off worm bearing adjuster 1/4 turn. (Scheme 1) CAUTION: DO NOT turn wheel hard against stop with steering linkage disconnected or steering gear may be damaged.
2. Remove horn button. Turn wheel to right stop and back off 1/2 turn. Install INCH lb. torque wrench on steering shaft nut. Rotate steering shaft 90 degrees and note torque wrench reading.
3. Torque required to maintain wheel movement should be 5-8 INCH lbs. (.6-.9 N.m). If not within specification, tighten worm bearing adjuster clockwise to increase preload or counterclockwise to decrease preload.
4. Adjust and hold worm bearing adjuster while tightening lock nut. Recheck worm bearing preload.

OVER-CENTER PRELOAD

1. With worm bearing preload adjusted, turn worm shaft slowly from stop-to-stop while counting total number of turns. Turn shaft back to the exact center position.
2. Loosen lock nut and turn sector shaft adjuster screw (located in center of sector shaft cover) in until all lash is taken out of sector shaft. Tighten lock nut. Rotate worm shaft slightly off center then attach an INCH lb. torque wrench to worm shaft or steering wheel nut.
3. Rotate worm shaft back through center position and note rotating torque. Rotating torque should be 4-10 INCH lbs. (.5-1.1 N.m) in excess of worm bearing preload. Maximum torque should not exceed 16 INCH lbs. (1.8 N.m). If rotating torque is not within specification, adjust sector shaft adjuster screw.

Scheme 1

Note. Replacement fasteners must have the same part numbers as originals. Torque all fasteners and install NEW cotter pin.

TROUBLE SHOOTING

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

STEERING SERVICE PRECAUTIONS

Replacement fasteners must have the same part numbers as the originals. Tighten all fasteners to specification. Always use NEW cotter pins. When installing cotter pins, DO NOT back off castle nuts to align cotter pin hole. Tighten nut to next slot that lines up with hole.

DO NOT hammer on ball studs, or damage to threads may result. If threads are not clean and smooth, ball studs may turn in joint when nuts are tightened. Tie rod sleeve clamps must always be positioned as specified before tightening bolts.

Note. Adjust worm bearing preload prior to performing over-center preload adjustment. If steering gear is removed, install INCH torque wrench on worm shaft to check preload adjustments.

Removal

1. Set front wheels in straight-ahead position. Disconnect negative battery cable. Remove flexible coupling-to-steering shaft pinch bolt. Remove flexible coupling cover on "T" Series or shield on "S" Series. Place reference marks on coupling and shaft for reassembly reference. Remove lower clamp bolt and lower clamp from worm shaft.
2. Mark relationship of pitman arm-to-sector shaft. Remove pitman arm retaining nut. Remove pitman arm using Puller (J-6632-01). Remove steering gear mounting bolts and remove gear assembly.

Installation

To install, reverse removal procedure. Ensure all reference marks are aligned and flexible coupling pinch bolt is aligned with groove of the shaft.

Raise and support vehicle. Remove cotter pins and outer tie rod end nut. Using Wheel Stud and Tie Rod Remover (J-6627-A), remove outer tie rod ball studs from steering knuckle and inner tie rod ball studs from relay rod. Remove tie rod ends from adjuster tube. Loosen clamp bolts and unscrew assemblies.

To install, reverse removal procedure. Lubricate tie rod threads with chassis lubricant before installing. Inner and outer tie rod end threads must be adjusted equally within 3 threads. Adjust toe-in. See WHEEL ALIGNMENT SPECIFICATIONS & PROCEDURES article in the WHEEL ALIGNMENT section. Tie rod ends must rotate full travel and travel must be maintained during clamp tightening. (Scheme 2)

Scheme 2

Raise and support vehicle. Remove inner tie rod end nuts. Remove inner tie rod ends from relay rod. On "T" Series, remove steering damper nut from relay rod. Using Steering Linkage Puller (J-24319-01), remove steering shock absorber from relay rod. On all models, remove relay rod end nuts from pitman arm and idler arm. Using Steering Linkage Puller (J-24319-01), remove pitman arm and idler arm from relay rod. Remove relay rod. (Scheme 3)and (Scheme 4).

To install, reverse removal procedure. Using Steering Linkage Installer (J-29193 or J-29194), seat all tapers to 40 ft. lbs. (54 N.m). Tighten nuts to specifications. See TORQUE SPECIFICATIONS TABLE at end of this article. Adjust toe-in. Proceed appropriate WHEEL ALIGNMENT SPECIFICATIONS & PROCEDURES article in the WHEEL ALIGNMENT section.

Scheme 3

Scheme 4

IDLER ARM

Note. Replace idler arm assembly if an up and down force of 25 lbs. (11 kg), applied at relay rod end of idler arm, produces a lash of more than 1/8" (3 mm) in straight-ahead position.

Raise and support vehicle. Remove idler arm nut and bolt from tie rod end. Remove idler arm nut and spring washer from relay rod. Using Steering Linkage Puller (J-24319-01) remove idler arm from relay rod. Remove idler arm. (Scheme 5)

To install, reverse removal procedure. Using Steering Linkage Installer (J-29193 or J-29194) seat all tapers to 40 ft. lbs. (54 N.m). Tighten nuts to specifications. See TORQUE SPECIFICATIONS TABLE at end of article. Adjust toe-in. Proceed to appropriate WHEEL ALIGNMENT SPECIFICATIONS & PROCEDURES article in the WHEEL ALIGNMENT section.

Scheme 5

1. Disconnect air induction assembly. Slide up intermediate shaft cover. Mark intermediate shaft for reassembly. Remove intermediate shaft. Disconnect oil filter lines at crossmember bracket. Remove splash shield.
2. Remove pitman arm nut and spring washer from relay rod. Using Steering Linkage Puller (J-24319-01), remove pitman arm from relay rod.
3. Remove lower steering gear bolts. LOOSEN upper steering gear bolt. Rotate steering gear for pitman arm clearance at crossmember and support with block of wood.
4. Remove pitman arm nut and spring washer from sector shaft. Index mark arm-to-shaft position. Using Remover (J-6632-01) or Puller (J-29107), remove pitman arm from shaft. (Scheme 3)and (Scheme 4).

To install, reverse removal procedure. Tighten nuts to specifications. See TORQUE SPECIFICATIONS TABLE at end of article. DO NOT hammer on pitman arm, or damage to steering gear may result. Be sure to reinstall hardened steel washer before installing nut.

Removal ("T" SERIES)

Remove steering shock damper nut from relay rod. Using Steering Linkage Puller (J-24319-01), remove steering shock damper form relay rod. Remove cotter pin, nut and bolt from frame mount end. Remove steering shock damper. (Scheme 4)

To install, reverse removal procedure. Using Steering Linkage Installer (J-29193 or J-29194), seat all tapers to 40 ft. lbs. (54 N.m). Tighten nuts to specifications. See TORQUE SPECIFICATIONS TABLE at end of this article. Adjust toe-in. See appropriate WHEEL ALIGNMENT SPECIFICATIONS & PROCEDURES article in the WHEEL ALIGNMENT section.

1. Seal may be replaced with steering gear installed. (Scheme 1) Set front wheels in straight-ahead position. Mark relationship of pitman arm-to-sector shaft. Using Puller (J-6632-01), remove pitman arm.
2. Remove sector shaft cover bolts. Lift sector shaft and side cover assembly from housing. Pry sector shaft seal from housing using a screwdriver. DO NOT scratch housing bore. Remove sector shaft adjuster screw lock nut. Remove sector shaft cover from sector shaft assembly by turning adjuster screw clockwise.
3. Inspect gear lubricant for contamination. If lubricant is contaminated in any way, gear should be completely rebuilt.

1. Lubricate new sector shaft seal with steering gear lubricant. Position seal in sector shaft bore and tap it into place using a socket.
2. Install sector shaft in gear so center tooth of sector enters center tooth space of ball nut. Fill gear housing with lubricant and install new side cover gasket on gear housing. Install side cover over sector shaft by reaching through cover hole with a screwdriver.
3. Turn sector shaft adjuster screw counterclockwise until screw bottoms and then back off screw 1/4 turn. Install sector shaft cover bolts and sector shaft adjuster lock nut. Adjust worm bearing preload and over-center preload. See WORM BEARING PRELOAD ADJUSTMENT and OVER-CENTER PRELOAD ADJUSTMENT.
4. Install pitman arm on sector shaft using marks made at removal. Tighten pitman shaft-to-sector shaft nut to specification. See TORQUE SPECIFICATIONS TABLE at end of article.

DISASSEMBLY

1. Place steering gear in a vise, clamping onto one mounting tab. Worm shaft should be in a horizontal position. Rotate worm shaft from stop-to-stop while counting total number of turns. Turn shaft back to the exact center position.
2. Loosen sector shaft adjuster screw lock nut. Remove sector shaft cover bolts. Lift sector shaft cover and sector shaft from housing.
3. Loosen worm bearing adjuster lock nut. Remove worm bearing adjuster with bearing and bearing race. (Scheme 1) Remove ball nut and worm shaft assembly. CAUTION: DO NOT allow ball nut to rotate down to either end of worm shaft, as ball guide ends may be damaged.
4. Remove remaining bearing from housing. Using screwdriver, pry bearing retainer from worm bearing adjuster assembly and remove bearing. Remove sector shaft adjuster screw lock nut.
5. Hold sector shaft cover and turn sector shaft adjuster screw clockwise to remove sector shaft cover. Remove sector shaft adjuster screw and shim from sector shaft. Pry out and discard both sector shaft and worm shaft seals.

CLEANING & INSPECTION

Clean components with solvent and dry with compressed air. Inspect bearings and races for signs of wear. Inspect sector shaft fit at side cover. Check ball nut and worm shaft assembly for wear and straightness.

Sector Shaft Bearing Replacement

Support steering gear in an arbor press. Using Bearing Remover (J-6278), drive sector shaft bearing from housing. Using Bearing Installer (J-35469 and J-8092), install new bearing into housing. Replacement bushings are machined to size and require no reaming.

Worm Shaft Bearing Race (In Worm Bearing Adjuster)

Using Slide Hammer (J-29369-1), remove bearing race from worm bearing adjuster. Using Bearing Race Installer (J-35365), install bearing race in worm bearing adjuster.

Worm Shaft Bearing Race (In Housing)

Using a hammer and punch, remove bearing race from housing. Using Bearing Race Installer (J-35365), install new bearing race in housing.

Ball Nut & Worm Shaft Assembly

Ball nut disassembly is only necessary if binding or tightness exists while rotating worm shaft. If disassembly is required, proceed to step 1).

1. Remove ball guides retaining clamp. Pull guides from ball nut while catching balls in clean pan. Turn nut over and rotate worm shaft until all balls have been removed.
2. Remove worm shaft from the ball nut. Wash parts and inspect worm, nut grooves, and ball bearings for indentations. Check ball guides for damage at ends where they deflect or pick up balls from helical path on worm shaft.
3. Measure distance between ball grooves of worm gear. Distance between grooves determines amount of balls to be installed in each circuit. See BALL USAGE TABLE. BALL USAGE Groove Distance - In. (mm) Balls Per Circuit .04 (1.0) 25 .10 (2.5) 27 .20 (5.0) 27
4. To reassemble ball nut and worm shaft, install ball nut with narrow end of ball nut teeth upward on right side (looking from steering wheel end of worm shaft). Install worm shaft. Ensure worm shaft is aligned with grooves in ball nut.
5. Install guides in ball nut. Install proper amount of balls in one guide hole while rotating the worm shaft. Repeat procedure for the remaining guide. Install guide clamps and bolts.

REASSEMBLY

1. Place gear housing in a vise with worm shaft bore horizontal and side cover opening facing upward. All seals, bushings and worm shaft bearing races should be installed.
2. Place upper ball bearing over worm shaft. Install worm shaft and ball nut assembly into housing and up through the upper ball bearing race and seal. Install bearing and retainer in worm bearing adjuster.
3. Install worm shaft and worm bearing adjuster in housing. Tighten worm bearing adjuster until a slight amount of worm shaft end play exists. Install sector shaft adjuster screw and shim in slotted end of sector shaft.
4. Using feeler gauge, check clearance between adjuster screw and sector shaft when holding adjuster screw upward. Clearance should not exceed .002" (.05 mm). If clearance exceeds specification, a different thickness shim should be installed.
5. Rotate worm shaft until ball nut is at center of its travel. Install sector shaft assembly so center tooth of sector teeth enters center tooth space in ball nut.
6. Install side cover gasket. Install side cover over sector shaft by reaching through cover with a screwdriver.
7. Turn adjuster screw counterclockwise until screw bottoms and then back off screw 1/2 turn. Loosely install a new lock nut onto adjuster screw.
8. Install sector shaft cover bolts. Adjust worm bearing preload and over-center preload. See WORM BEARING PRELOAD and OVER-CENTER PRELOAD ADJUSTMENT.

WHEEL ALIGNMENT

After performing appropriate service procedures, refer to WHEEL ALIGNMENT SPECIFICATIONS & PROCEDURES article in the WHEEL ALIGNMENT section.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS