Steering Gear - Power Ford Cab & Chassis Ranger

DESCRIPTION

Torsion bar type power steering unit consists of a worm and one-piece rack-piston, which is meshed to gear teeth on sector shaft. Hydraulic control valve, input shaft, and torsion bar assembly are mounted to end of worm shaft and operated by twisting action of torsion bar.

One-piece rack-piston, worm and sector shaft are mounted in one housing, while valve spool is mounted in an attached housing. This allows internal passage of fluid between valve and cylinder, thus eliminating all external lines and hoses, except for pressure and return hoses between pump and gearbox assembly.

TROUBLE SHOOTING

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

LUBRICATION

Check fluid level in pump reservoir (with engine at normal operating temperature) every 5000 miles.

OVER-CENTER POSITION

1. Disconnect pitman arm from sector shaft using Pitman Arm Puller (T64P-3590-F). Disconnect fluid return line at pump reservoir, and cap reservoir return line pipe. Place end of return line in clean container and cycle steering wheel in both directions several times to discharge all fluid from steering gearbox.
2. Remove horn button from steering wheel, and turn steering wheel until positioned 45° from left steering stop. Using an INCH lb. torque wrench on steering wheel attaching nut, measure force required to turn steering shaft 1/8 turn from 45° position.
3. Turn steering wheel back to center position and measure force required to move steering shaft back and forth across center position.
4. Loosen lock nut and turn adjusting screw until reading across center position is 14-18 INCH lbs. (1.6-2.0 N.m) greater than reading across 45° position. Tighten lock nut while holding adjusting screw in place. Replace pitman arm and reconnect hoses.

Ford Torsion Bar Steering Gear Assembly. Scheme 4

VALVE SPOOL CENTERING

1. Install a 0-2000 psi pressure gauge and valve assembly between power steering pump and high pressure line. Open gauge valve completely, and remove horn button from steering wheel. Attach an INCH lb. torque wrench to steering wheel attaching nut.
2. Power steering fluid must be at normal operating temperature and at correct level. Steering wheel must be in centered position and engine at normal operating temperature.
3. Set engine idle to 1000 RPM. Using torque wrench, rotate steering shaft to either side of center to obtain gauge reading of 250 psi (17.5 kg/cm 2 ) in each direction.
4. Torque reading should be equal in both directions when 250 psi (17.5 kg/cm 2 ) is reached. If difference between readings exceeds 6 INCH lbs. (.68 N.m), steering gear must be removed and shaft and control assembly replaced.

Note. When performing test off vehicle, use same procedure, except take torque and pressure readings at right and left stops instead of either side of center.

Removal

1. Disconnect hydraulic lines at power steering gear, and cap lines. Plug ports in steering gear to prevent entry of foreign matter. Remove splash shield from flex coupling. Disconnect flex coupling at steering gear.
2. Raise vehicle and remove pitman arm nut and washer. Using Pitman Arm Puller (T64P-3590-F), remove pitman arm from sector shaft, being careful not to damage seals.
3. Support steering gear and remove steering gear attaching bolts. Work steering gear free of flex coupling and remove steering gear from vehicle.

Installation

1. Slide flex coupling into position on steering shaft assembly and turn steering wheel so spokes are in horizontal position. Center steering gear input shaft with indexing flat facing down.
2. Install gearbox input shaft into flex coupling and into place on frame. Install and tighten attaching bolts. With wheels in straight ahead position, install pitman arm on sector shaft. Install washer and nut on pitman arm and tighten.
3. Install splash shield. Connect and tighten pressure and return lines to steering gear. Disconnect coil wire. Fill reservoir to proper level. Turn ignition on and turn steering wheel left to right to distribute fluid. Check fluid and add if necessary.

OVERHAUL

Note. If complete gearbox assembly is to be overhauled, remove unit to be overhauled and proceed to disassembly and reassembly of that unit.

Disassembly

1. Drain steering gear completely, and mount gear in a soft-jawed vise. Remove lock nut and washer from adjusting screw. Turn input shaft to either stop, then turn shaft back 2 turns to center gear.
2. Remove sector shaft cover attaching bolts. Tap lower end of sector shaft with a soft faced hammer to loosen shaft in bore, then lift shaft and cover assembly from housing. Discard cover "O" ring.
3. Turn sector shaft cover counterclockwise to remove it from adjusting screw. Remove valve housing attaching bolts and identification tag. Lift valve housing from steering gear housing while holding piston to prevent it from rotating off worm shaft.
4. Remove valve housing and control valve gasket. Discard gasket. With piston held so that ball guide faces up, remove ball guide clamp screws and ball guide clamp.
5. Over a clean container, place finger over opening in ball guide, turn piston so ball guide faces down and let guide tubes fall into container.
6. Rotate input shaft stop to stop until all balls fall from piston into container. Remove valve assembly from piston. Inspect piston bore to ensure all balls have been removed.
7. Install valve body assembly in bench mounted Holding Fixture (T57L-500-B) or vise. Loosen hex head race nut screw from bearing race nut. (Scheme 5) Carefully slide input shaft, worm and valve assembly out of valve housing.

Removing Worm Bearing Race Nut. Scheme 5

Scheme 6

1. Mount valve housing in a holding fixture with flanged end upward. Apply a light coat of lubricant to Teflon rings on valve sleeve, then carefully install worm and valve in housing.
2. Install race nut in housing and tighten securely. Install Allen head race nut set screw through housing and tighten. Place piston on bench with ball guide holes facing up.
3. Insert worm shaft into piston so that first groove is in line with hole nearest center of piston. Place ball guide in piston. Place a minimum of 27 ball bearings in ball guide while turning worm counterclockwise as viewed from input end of shaft. (Scheme 6): Installing Piston on Worm Shaft Rotate worm while installing balls.
4. If all balls have not been fed into guide upon reaching left stop, rotate input shaft in one direction and then other while inserting remaining balls. DO NOT rotate input shaft more than 3 turns from left stop or balls will fall out of circuit.
5. Secure guides in ball nut with guide clamp. Apply petroleum jelly to Teflon seal on piston and place a new "O" ring on valve housing. Slide piston and valve into gear housing, using care not to damage piston ring.
6. Align oil passage in valve housing with passage in gear housing. Place new "O" ring in oil passage hole of gear housing. Install identification tag on housing on upper right valve housing bolt.
7. Loosely install housing attaching bolts, rotate ball nut so that teeth are in same place as sector teeth and tighten valve housing bolts. Position sector shaft cover "O" ring in steering gear housing. Turn input shaft as necessary to center piston.
8. Apply petroleum jelly to sector shaft journal, and position sector shaft and cover assembly in gear housing. Install and tighten cover attaching bolts. Adjust steering over-center position. See «OVER-CENTER POSITION»(/ford/cab-chassis-ranger/1985-1986/remont/manual-power-steering/#steering-gear-power__over-center-position).

Disassembly & Reassembly

1. Remove snap ring from lower end of housing. Using Puller Attachment and Slide Hammer (T58L-101-A and T59L-100-B), remove dust seal and pressure seal from housing. Lubricate new seals and sector shaft seal bore with Lubriplate.
2. Place dust seal on Seal Installer (T77L-3576-A) so raised lip of seal is toward installer. Place pressure seal on installer so lip is facing away. Flat back side of pressure seal should be against flat side of dust seal.
3. Insert installer into sector shaft bore and drive in until seals clear snap ring groove. DO NOT bottom seals against bearing. Install snap ring in housing groove.

Disassembled View of Control Valve Housing. Scheme 7

1. Using Puller Attachment and Slide Hammer (T58L-101-A and T59L-100-B), remove dust seal from rear of valve housing. Discard seal. Remove snap ring from valve housing. Invert valve housing.
2. Using Input Shaft Bearing and Seal Remover (T65P-3524-A2 and T65-3524-A3) in valve body assembly opposite oil seal end, tap bearing and seal out of housing.
3. Discard dust seal. Remove fluid inlet and outlet tube seats with Tube Seat Remover (T74P-3504-L) if damaged.

Reassembly

1. Coat fluid inlet and outlet tube seats with petroleum jelly and install them in housing. Install bearing with metal side covering rollers facing outward. Press bearing into housing.
2. Dip a new oil seal in power steering fluid and place in housing with metal side out. Drive seal into housing until outer edge does not quite clear snap ring groove.
3. Install snap ring in housing. Place dust seal in housing with dished rubber side out. Drive into place until seal is located behind undercut in input shaft.

Disassembled View of Ball Nut & Housing. Scheme 8

1. Remove rings from sleeve with a small knife. Mount worm end of worm and valve sleeve assembly in a soft-jawed vise. Install Mandrell (T75L-3517-A1) over sleeve. Install rings one at a time with aid of a Driver (T75L-3517-A2).
2. Rapidly push down on driver to force ring down ramp and into fourth groove of valve sleeve. Repeat three more times, each time adding Spacers (T75L-3517-A3) under mandrell to line up next groove.
3. After all sleeve rings are installed, install Sizer (T75L-3517-A4) carefully over valve sleeve rings. Ensure rings are not bent over when tube is slid over them. Remove sizer and check condition of rings. They must turn freely.

Remove teflon ring and "O" ring from piston and ball nut assembly. Dip new "O" ring in power steering fluid and install it on piston and ball nut. Install new teflon ring on piston and ball nut, using care not to stretch ring more than necessary.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

See also:
• TROUBLE SHOOTING - BASIC PROCEDURES
• OVER-CENTER POSITION