SECTION 57 STEERING STAG

The steering-wheel, steering-column, and related components are shown in Fig. 57.0 1. The steering column comprises an upper shaft and a lower shaft, connected by a needle-bearing universal joint. The upper shaft is supported by a housing to which the light, trafficator, wiper stalks, and steering lock controls are fitted. The lower shaft is telescopic and is enclosed and supported by a two-piece tubular housing. In the event of impact, due to collision, both the lower shaft and its housing will collapse and prevent the steering-wheel being thrust towards the driver. (Fig. 57.02.)

An intermediate shaft connecting the rack pinion and the steering-column lower shaft is fitted with two splined universal joints. All universal joints are lubricated on assembly and require no attention in service.

Steering-column adjustment for both axial movement (4 in., 102 mm.) and rake (2 in., 51 mm.), is provided by a single clamp lever located in front of the nacelle.

The 16 in. (407 mm.) three-spoke steering-wheel incorporates a padded rim and boss. Four turns are required from lock to lock.

POWER STEERING EQUIPMENT

Power steering equipment shown in Fig. 57.03 comprises an hydraulic pump, a combined steering rack and ram chamber, and a control valve and pinion assembly.

The function of the power steering equipment is to minimize the physical effort of turning the steering-wheel, especially when parking or maneuvering in restricted space. The input torque to operate the steering unit is IO lb. in. (0- 1 15 kg m.) per degree.

When the engine is not running, or if for any reason the hydraulic system is inoperative, the vehicle can be steered by direct mechanical effort.

The engine-driven hydraulic pump supplies pressurized oil to a rotary-type spool valve which forms an extension of the rack pinion shaft. Movement, imparted to the rotary valve from the steering column is via a torsion bar, the deflection of which determines the relationship of the spool ports and thus the hydraulic power to be directed to one or other side of the steering-rack piston.

Initial power assistance is obtained at approximately " deflection of the torsion bar. Maximum assistance is obtained at approximately 4' deflection of the torsion bar. When the torsion bar is deflected to approximately 7', direct mechanical drive is obtained.

The hydraulic pump

Description

A combined hydraulic pump and fluid reservoir unit, shown sectioned in Fig. 57.04, is secured to the engine by two brackets and belt-driven from the engine crankshaft pulley. Two flexible hoses one delivery, one return-connect it to a control valve on the steering-rack.

A rotor with 10 floating vanes is fitted to the pump shaft and is enclosed by an elliptical ring which provides two diametrically opposed pumping chambers. Fitted front and rear of the rotor are, respectively, a thrust plate and a pressure plate. These plates employ dowel pins to align them with the elliptical ring and pump body. A tapered compression spring, assisted by pump output pressure, maintains controlled loading of the pressure plate. An end-plate located by a circlip and sealed by an 'O' ring provides a division between pump and reservoir.

Below the rotor, from which it is supplied, is a combined flow valve/relief valve, and the pump delivery union. Oil, returned from the rack control valve, is fed directly to the reservoir.

Operation

Oil, from the reservoir, is admitted via a drilling in the pump body to the underside of the pump rotor, from whence, through portings between the rotor and thrust plate and also the rotor and pressure plate, it is admitted to the pumping chambers. From the pumping chambers the oil is expelled to the discharge chamber, and, via a drilling in the pump body, to the pump outlet union. Pressurized oil in the discharge chamber is also admitted to the vane roots, thus ensuring that the vane tips follow the contours of the elliptical ring.

At the pump outlet union the oil passes via a slot on the piston crown of the flow/relief valve and is delivered to the rack control valve.

As its name suggests the flow/relief valve serves a dual function, namely to provide escape for pressurized oil when steering demands require limitation (for example, when the road wheels are on full lock and excessive pressure would overload the rack seals), and also to ensure that oil flow is adequate to pressurize the rack chamber as required.

Briefly, the flow/relief valve comprises a piston, the crown of which is exposed to pump pressure, the other end bears against a compression spring. Within the piston is a spring-loaded ball-type relief valve. Fig. 57.04 shows the flow/relief valve and its associated ports. The need for high rack chamber pressure is greatest when maneuvering or parking and usually coincides with reduced pump speeds and high frictional resistance between tyre and road due to zero or low rolling speed. The flow/relief valve therefore has to cater for a range of flow and pressure variations ranging from high volume flow and no steering demands (vehicle traveling in straight line at high speed), and low volume flow and maximum steering demands (vehicle stationary, engine idling, full lock).

From Fig. 57.04 it will be evident that pump discharge pressure, acting on the piston of the flow valve, will tend to displace the piston against the action of its compression spring, thereby increasing oil flow through the outlet union, to the rack control valve, or, when the piston is displaced sufficiently, to uncover the escape port, allowing oil to return to the reservoir. This latter position is the normal working position of the piston, as discharge from the pump is always in excess of power steering requirements and oil is constantly being circulated externally. However, oil admitted to the outlet union also has access, via an orifice and transfer passage, to the spring chamber of the flow piston where it is further assisted by the spring.

Since piston area, front and rear, are equal, given hydraulic balance the spring will oppose pump pressure and tend to restrict piston displacement, but since movement of the piston towards the outlet union must create restriction in oil flow and a consequent pressure increase, the piston adjusts bleed off or escape to the reservoir to match the pressure and flow requirements of the rack control valve. Influence on piston displacement is also applied by the orifice in the transfer passage to the spring chamber as its presence introduces a delay factor in pressure adjustment between spring chamber and piston crown. The interaction of these forces causes the flow piston to be hydraulically self-compensating to match pump pressure with steering power requirements, and by means of the relief valve to impose Imitation on pressure increases within 750 to 850 p.s.i. (52-73 to 59-76 kg./cm.2).

Maintaining the hydraulic pump

Attention to the hydraulic pump in service requires only that the fluid level is maintained at the high mark on the reservoir dipstick, and that the drive belt is not damaged or unduly worn, and is adequately tensioned.

Dismantling the hydraulic pump (Refer Fig. 57.05)

Where 'front' and 'rear' are mentioned, interpret 'front' to indicate pulley end of pump.

Drain oil from reservoir and clean exterior of pump.
Remove nut and washer securing pulley to shaft.
Using a suitable puller withdraw pulley. Do not attempt to hammer shaft from pulley, or lever pulley from shaft as this may cause internal damage to pump.
Withdraw Woodruff key from pump shaft.
Remove mounting bolts and studs from front and rear of pump body.
Remove pressure outlet complete with 'O'ring and withdraw relief valve/flow valve and spring.
Separate reservoir from pump body.
Remove circlip securing end-plate. To facilitate the removal of this circlip a small hole is drilled in the body casing to permit the insertion of a pin punch or stiff wire (Fig. 57.06).
Withdraw end-plate and spring, and extract end-plate 'O' ring from pump body.
Carefully slide pump shaft to rear of body and withdraw shaft complete with pressure plate, thrust plate, and rotor assembly.
Remove thrust plate, dowel pins, eccentric ring, and rotor vanes, and examine all components.
The thrust plate and rotor hub may be separated from the pump shaft by removing the circlip from the shaft.

Assembling the hydraulic pump (Refer Fig. 57.05)

Where 'front' and 'rear' are mentioned, interpret 'front' to be pulley end of pump.

Ensure all components are thoroughly clean. The shaft oil seal, and all 'O' rings, should be renewed on assembly.

If the thrust plate and rotor hub have been disturbed, fit them to shaft and secure with new circlip. Ensure ported face of thrust plate is adjacent to rotor hub.
Lubricate shaft bush and lips of oil seal and carefully enter shaft in pump body.
Align pressure plate dowel holes with pump body and insert the two dowel pins.
Locate eccentric ring on dowel pins, making sure rotation arrow is to rear of pump.
Fit vanes to rotor hub slots (curved edges of vanes towards eccentric ring).
Using hydraulic fluid, lubricate eccentric ring, vanes, and rotor hub.
Install pressure plate 'O' ring in pump body and smear with hydraulic fluid.
Enter pressure plate evenly in body (ported face towards rotor hub) and engage dowel pins. Press gently into position (hand only).
Fit end plate 'O' ring to pump body.
Locate tapered coil spring in pump body, engaging larger diameter coil in recessed seat in pressure plate.
Smear perimeter of end plate with hydraulic fluid and evenly insert end plate into pump body until it is slightly below groove of retaining circlip.
Fit circlip to pump body and release end plate.
Fit reservoir 'O' ring to pump body.
Fit rubber seals into recesses in rear face of pump body.
Carefully and evenly slide reservoir over pump body, ensuring that mounting holes are aligned and mounting bolt sealing rings are not dislodged.
Fit reservoir mounting bolts and studs.
Insert relief valve spring, relief valve/flow valve.
Fit new 'O' ring to outlet union and screw union into position.
Install key in drive shaft and fit pulley and securing nut.

The power steering rack and control valve (Refer Fig. 57.03)

The power steering rack is similar to normal rack-type mechanisms except that the rack shaft is fitted with a single piston which operates in an enclosed sealed chamber. By means of the spool-type control valve/pinion assembly, pressurized oil from the engine-driven hydraulic pump is directed to one or other side of the rack piston, thus providing power assistance to deflect the front road wheels as required.

Dismantling power steering rack (Refer Fig. 57.07)

Remove rack complete from vehicle.
Slacken clips securing bellows seals and slide bellows seals along tie-rods to expose inner ends of tie-rods.
Wipe inner ends clear of grease and straighten tab ends of innermost lock washers.
Unscrew tie-rods from rack. Care must be taken not to disturb adjustment of the inner ball joint.
Disconnect unions connecting rack pipes to control valve and rack chamber, and remove pipes.
Slacken locknut on rack plunger adjusting screw and withdraw adjusting screw, spring, and plunger.
Remove the three Nyloc nuts and washers securing control valve flange to rack and withdraw control valve and gasket.
Withdraw seal housing and washer from rack.
Disconnect unions securing rack balance pipe and remove balance pipe.
Using a suitable 'C' spanner, release screw securing end-housing to rack cylinder and withdraw end-housing,
Remove union from centre of rack clinder.
Withdraw rack shaft complete with piston in direction of end-housing.

NOTE: This operation invariably results in the rack teeth being drawn through the lip-type seal in the cylinder sleeve. It is essential that this seal is renewed when the rack shaft is removed. It is recommended that all seals are renewed once they have been disturbed.

13. Withdraw cylinder sleeve from bore of cylinder.

14. Remove circlips and extract piston from rack shaft. Take care that circlips do not score rack shaft.

Assembling power steering rack (Refer Fig. 57.07 )

Thoroughly clean all components.
Fit new seal and nylon backing ring to cylinder sleeve. Note that seal lip must be fitted adjacent to tapped locating hole and that square edge of nylon ring must abut against seal.
Fit new 'O' rings to cylinder sleeve and lubricate cylinder bore with hydraulic oil.
Lubricate seal lip and enter cylinder sleeve (seal leading) over rack shaft at opposite end to rack teeth.
Fit piston inner 'O' ring to rack shaft.
Carefully slide cylinder sleeve (seal end first) along plain end of rack shaft beyond location of piston. Do not slide cylinder sleeve over rack teeth.
Fit piston inner circlip to rack shaft, taking care not to mark or score rack shaft.
Fit piston ring to piston, slide piston into position on rack shaft and secure with circlip, taking care not to score or mark shaft.
Align tapped hole in cylinder sleeve with countersunk hole in cylinder and carefully slide sleeve and rack shaft into cylinder (Fig. 57.08).
Through countersunk hole in cylinder, locate tapped hole in cylinder sleeve.
Ensure end-cover securing ring towards open end of cylinder, smear conical seat of union with hydraulic sealing compound and fit and tighten union securing cylinder sleeve.
Fit new lip-type seal (lip of seal towards cylinder bore) and 'O' ring to end cover.
Lubricate seal lip and slide end cover into position
Line up mounting feet and secure end cover by tightening screwed retaining ring.
Fit lip seal and 'O' ring to retainer. Fit washer into recess in pinion housing and fit ring (lip seal downwards). (Fig. 57.09.)
Fit new gasket to control valve flange.
Locate rack shaft in cylinder so that rack teeth are visible through control valve flange and are aligned to permit engagement of pinion.
Carefully enter pinion through seal and engage rack teeth, locating control valve over studs. Fit and tighten the three Nyloc nuts.
Rotate pinion until rack is centralized, i.e. the dimple on rack shaft lies in the middle of the thi-ust plunger aperture. (Fig. 57.10.)
Remove the small hexagonal plug from the screwed plug and using a dial gauge tighten screwed plug until plunger end-float (i.e. side movement of the rack shaft) does not exceed 0.007 in.
(0.178 mm.). This measurement must not be confused with backlash or axial movement. Tighten locknut.
Fit grease nipple to screwed plug and grease rack.
Remove grease nipple and replace hexagonal plug.
Fit new end washers complete with 'D' plates to rack ends (recessed side of washer towards rack).
Fit and tighten tie-rod inner ends to correct torque figure. Both tie-rod inner ends should be tightened simultaneously to prevent stress to pinion. Secure by bending over lock tabs on 'D' plates, care being taken not to disturb ball housing tabs. Ball joints to be checked for free articulation following assembly to rack.
Grease rack ends and inner ball ends, slide bellows seals into position, and secure with clips.
Fit Bundy tubing to control valve and rack housing.

If necessary, during assembly of rack, the pinion lower needle bearing and rack shaft bush in end housing can be renewed.

The control valve

Description and operation

The steering rack control valve is a combined pinion shaft and spool valve assembly through which oil flow from the hydraulic pump is directed to either side of the rack piston as required. A cutaway view of the control valve is shown in Fig. 57.11 together with a sectioned plan view (Fig.57.12). From these illustrations the construction and principle of operation can be seen.

The ports in the control valve body are connected, in order of descent, as follows:

Top-return to reservoir.
1st intermediate-delivery to, or return from one side of rack piston.
2nd intermediate-pressure supply from pump.
Bottom-delivery to or return from other side of rack piston.

Forming the spool valve is a shaft with six flutes, three long and three short, alternately disposed. This shaft is encased by a sleeve which has six internal axial channels, and on its external surface, three circumferential grooves interspaced with sealing rings. The centre circumferential groove has three drillings at 120' which penetrate the plain area of the internal bore. The top and bottom circumferential grooves also are drilled, but these holes (three at 120' each groove) are smaller than those of their centre counterpart and penetrate the top and bottom respectively of the internal axial channels as shown in Fig. 57.13. When assembled, the shaft and sleeve are as shown in Fig. 57.12, i.e. with the centre circumferential groove drillings aligned with the short flute and the smaller drillings in the top and bottom grooves aligned with the plain (unfluted) surface of the shaft. As illustrated (Fig. 57.12) this is neutral or straight-ahead position, a position which requires no steering assistance. This delicate relationship of sleeve and shaft is the responsibility of the eccentric screw shown in Fig.57.11. No adjustment must be made to the eccentric screw in service.

So long as the hydraulic pump is running, oil is delivered under pressure to the central circumferential groove of the sleeve, and, via its three drillings, to the short flutes machined in the shaft.

A feature of the shaft flutes is the carefully ground tapered chamfers at the flute sides. These chamfers allow oil to flow, in neutral, to adjacent sleeve channels and also to the long flutes, where, with escape unrestricted, the oil can pass above the sleeve and return to the pump reservoir. The flute chamfers, however, serve the system in other ways: their presence prevents abrupt changes in pressure differentials, and also, because of the characteristics of oil flow, together with the torsion bar, provides the retention of driver 'feel'.

When the steering-wheel is turned to right or to left the deflection of the torsion bar to which the control valve shaft is pinned allows the shaft to move initially independent of the sleeve, thus altering the relationship of the shaft flutes to the internal axial channels of the sleeve. The result is that oil is now supplied to three of the sleeve internal channels only and is passed to either the top (left-hand turn) of the sleeve circumferential groove from whence it is fed to the appropriate side of the rack piston. Since pressure on one side of the rack piston necessitates oil displacement on the other side, the displaced oil from the unpressurized side of the rack piston is returned to the sleeve circumferential groove which is not pressurized and escapes to the reservoir via the long flutes.

When the torsion bar is no longer subjected to deflection, i.e. when effort has ceased to be applied to the steering-wheel rim, the shaft flutes are restored to their neutral position (Fig. 57.12) and pressure differences within the ram chamber cancelled.

Attention to the control valve is not recommended as its construction and setting does not favour dismantling. Where, however, the top oil seal requires renewal, this operation may be carried out provided care and scrupulous cleanliness are observed. It is necessary to emphasize that the eccentric screw locating the spool sleeve MUST NOT be disturbed.

Removing and replacing control valve top seal (Refer Figs' 57.11 and 57.14)

Thoroughly clean exterior of control valve end unions.
Disconnect flexible hoses and steel pipes at control valve and seal all apertures to prevent ingress of grit.
Release plunger load from rack shaft.
Remove the three Nyloc nuts from control valve flange and withdraw control valve.
Carefully press pinion shaft and extract pinion and shaft from underside of control valve. Note that pressure must not be applied to the pinion shaft torsion bar.
The withdrawal of the pinion shaft will expose the spool valve which is fitted with special sealing rings and is located by an eccentric screw (Fig. 57.14). Neither the special rings nor the eccentric screw are to be disturbed in any way. Disregard of this instruction may result in a requirement for a new control valve.
Remove circlip, backing washer and seal from control valve body; renew seal and replace in reverse order.
Using special sleeve (Tool No. J-34), insert pinion shaft and spool valve into body.
Remove special sleeve (Tool No. J-34) from pinion shaft.
Refit control valve to rack, ensuring pinion teeth do not damage lip of control valve lower seal.
Adjust and lock rack plunger.

Removing and replacing control valve seat inserts

Seat inserts are fitted to the inlet and return ports of the control valve housing. These seats can be damaged due to over tightening of the flexible hose unions.

Seat removal can be accomplished by using an 'Easy-Out' extractor. Carefully fit a new insert, observing scrupulous cleanliness as the admission of swarf or grit may render the control valve inoperative.

IMPORTANT: The insert in the control valve pressure inlet port is also a restrictor. This insert, or restrictor must be chosen to suit the hydraulic pump fitted.

Bleeding the steering system

The hydraulic steering system is self-bleeding, but care must be taken to ensure that at no time is the pump reservoir allowed to empty or become dangerously low. This is especially important where both the pump and the rack have been newly installed.

When the hydraulic system has been disturbed, proceed as follows.

Ensure all hydraulic connections are properly made and tight.
Fill hydraulic reservoir to high level mark on dipstick.
Place road wheels in straight-ahead position, and with drive belt slackened or removed rotate pump pulley by hand to prime system.
Fit and adjust drive belt.
Check, and top up hydraulic reservoir as necessary.
Start engine and allow to idle.
Turn driving wheel to full lock and return wheel to straight-ahead position.
Check and top up reservoir.
Turn driving wheel to opposite lock and return to straight-ahead position.
Again check reservoir level.
Turn wheels from lock to lock several times to permit air to be fully exhausted from system.
Return wheel to straight-ahead position and give final check to reservoir level.

NOTE: While repeated turning of the steering-wheel when the car is stationary will do the steering mechanism and hydraulic units no harm, the effect on tyre treads is not so favourable. When testing or bleeding the power steering, the road wheels should be rotating slowly to minimize tyre scrub.

Testing the steering system

Should steering defects arise in service, careful analysis is advised before attributing blame to the power steering equipment and embarking on the dismantling of hydraulic units. Heavy steering and pull to one side may be caused by mechanical faults; wheel track, tyre treads, tyre pressures, wheel bearings, steering geometry, and wear and stiffness in linkage must first be checked.

Where examination eliminates mechanical faults, the testing of the hydraulic system is explained

below.

1. Check reservoir level and carefully examine steering units and hoses for leaks. All leaks must be rectified before attempting to test system.

2. Check pump drive belt for condition and tension.

3. Release rubber bellows seals from rack-ends and examine for fluid leakage.

4. Fit test gauge (JD10 and adaptor 10-2) to pump delivery (outlet) line as shown in Fig. 57.15.

5. Ensure all air is exhausted from the circuit, the oil level in the reservoir is correct, and that the oil is at working temperature.

6. With test-cock open and engine running, gently turn steering-wheel to left and right lock whilst observing gauge. A pressure of 750 to 859 p.s.i. (52.73 to 59.76 kg/cm2) should be recorded in both cases. If pressure within this range is not obtained, or marked pressure imbalance is recorded, a fault exists in the system.

7. To determine if the fault is in the rack circuit or in the pump, close the test-cock for a period not exceeding five seconds. If the gauge fails to register 750 to 850 p.s.i. (52.73 to 59.76 kg/cm.2), the pump is inefficient and the pump relief valve/flow valve should be examined/renewed as necessary.

8. Repeat above test after renewing relief valve/flow valve and bleeding system. If the pump still fails to deliver oil at 750 to 850 p.s.i. (52.73 to 59.76 kg./cm .2) , attention to the pump, or a new exchange unit is required.

9. If pump delivery is satisfactory and low pressure or marked imbalance exists, the fault must be in the rack control valve, or be caused by internal leakage in the rack cylinder.

10. Remove rack cylinder pipe unions from rack control valve body. Using suitable plugs, seal rack cylinder ports in control valve body.

11. With engine idling, turn steering-wheel gently to left and right, observing gauge reading. Do not hold wheel in either direction for periods exceeding five seconds. Check that pressures of 750 to 850 p.s.i. (52.73 to 59.76 kg./cm.2) are obtained in both directions.

NOTE: Since fluid is now being supplied to the rack the steering will naturally be heavier. It is quite unnecessary, however, to attempt to impart movement to the road wheels since the object of this test is merely to record pressure obtained at maximum torsion bar deflection.

12. If the control valve is found satisfactory, the fault must be within the rack.

STAG STEERING FAULT DIAGNOSIS

FAULT	Cause	Remedy
Heavy steering	Pump drive belt slack Insufficient fluid in reservoir Incorrect tyre pressures Pump relief/control valve faulty Restricted orifice to relief/ control valve Constricted delivery or return hose Rack chamber or piston seals faulty Faulty rack control valve	Adjust belt tension. Top up reservoir. Adjust tyre pressures. Renew relief/control valve. Clear obstruction. Renew defective hose. Renew rack seals. Renew rack control valve.
Steering pulls to one side	Tyre pressures incorrect Tyre tread differential on front wheels excessive Loose or worn steering linkage Geometry incorrect Rack chamber or piston seals faulty Faulty rack control valve	Adjust tyre pressures. Fit equal treads to front wheels Rectify. Check and adjust. Renew rack seals. Renew control valve.
Backlash in steering-wheel couplied with insensitive handling	Loose or worn steering connections Defective torsion bar or sheared torsion pin	Tighten, adjust, or renew as necessary. Renew rack control valve.
Jerky or inconsistent response when turning	Pump drive belt slack Insufficient fluid in reservoir	Adjust belt tension. Top up reservoir.

SERVICING POWER STEERING COMPONENTS IN SITU

Adjusting hydraulic pump drive belt

See Engine, Section 12.

Renewing hydraulic pump drive belt

See Engine, Section 12.

Remove and replace relief/How valve

Raise car on ramp or jack.
Clean area in vicinity of flexible pipe unions on hydraulic pump.
Disconnect outlet union at pump. This will result in spillage of hydraulic fluid and a container should be available for this purpose.
Remove pump outlet union.
Withdraw relief/flow valve and spring.
Replace in reverse order, noting that filter end of valve is fitted adjacent to spring.
The outlet union 'O' ring should be renewed.
Top up reservoir, bleed system and check for leaks.

Removing and replacing flexible hoses (Refer Fig. 57.03)

Thoroughly clean areas in vicinity of flexible hose unions at control valve and hydraulic pump.
Disconnect unions at control valve and pump. (The oil return hose is fitted with a union at control valve end and a clip at pump end.)
Replace in reverse order.
Top up reservoir, bleed system and check for leaks.

Flexible hoses must be renewed if signs of chafing, softness, or perishing become evident. Do not use substitute hoses.

Removing and replacing hydraulic pump

Disconnect oil delivery and return pipes at hydraulic pump.
Remove nut and washers securing pump to rear bracket.
Slacken the two bolts securing pump to front bracket, pivot pump towards engine, and release drive belt from pump pulley.
Remove the two bolts securing pump to front bracket.
Remove nuts and washers securing rear bracket to engine cylinder block.
Withdraw pump and rear bracket.
Replace in reverse order.
Adjust belt tension, top up reservoir and bleed steering system.

Renewing tie-rod outer end

Remove road wheel.
Scribe a line on one flat of the tie-rod outer end locknut and a corresponding line on tie-rod. Slacken locknut.
Release tie-rod from steering-arm and unscrew tie-rod outer end.
Screw on new outer end, ensuring it will be located in the same position on the tie-rod as the old one. That is, that the length between ball centres is not altered.
Connect and tighten tie-rod end to steering-arm.
Repeat above procedure on opposite side.
Fit road wheels and check track, adjusting as necessary.

Wear in tie-rod outer ends cannot be removed by adjustment; renewal of the complete end is necessary. Tie-rod outer ends should be renewed in pairs.

Renewing bellows seal

Remove front wheel.
Remove tie-rod outer end and locknut.
Clean area around bellows.
Release clips securing bellows seal to rack housing and tie-rod and slide off bellows seal.
Ensure tie-rod inner end is adequately greased, pack new bellows seal with approximately 2 oz. of grease and slide into position.
Secure inner end of seal to rack with a clip or twist of wire, taking care not to cut or bite into seal.
Position outer end of bellows seal 5.75 in. (146 mm.) from outer end of tie-rod and secure with clip.
Replace locknut and tie-rod outer end and secure to steering-arm.
Fit front wheel, lower vehicle to ground and check and adjust wheel track as necessary.

Renewing tie-rod (Fig. 57.16)

Remove front wheel, disconnect tie-rod outer end from steering-arm and withdraw outer end and bellows seal.
Turn steering-wheel as necessary to expose tie-rod inner end.
Straighten lock tabs securing ball end to rack on inner lock washer.
Unscrew tie-rod.
Replace in reverse order, ensuring inner lock tabs are renewed and properly secured. Both tierod inner ends must be tightened simultaneously to prevent stress being applied to pinion teeth.
Check tie-rod inner ball joints for free articulation.
Check and adjust wheel track as necessary.

Tie-rod inner end (Fig. 57.16)

Wear in tie-rod inner ends can be adjusted by shim removal provided the ball end is not stepped and ovality is not present in ball seats.

Properly adjusted, and with tab washer securely locked, the tie-rod should pivot evenly about its seat. Stiffness in tie-rod articulation, whether throughout its movement or in spots, rhust not be tolerated.

End-float should be within 0.0005 to 0.003 in. (0.0127 to 0.0762 mm.).

The torque setting of ball housing to adaptor is 80 to 90 lb. ft. This is critical.

If ball joints are secured to rack at a higher torque it could result in the tab washer being disturbed and also overtightening of the ball joints.

Tie-rod length

Tie-rod lengths should be set initially to 9-74 in. (247-396 mm.) between ball centres. Subsequent adjustment made to obtain correct track setting should be made equally to both rods.

Removing and replacing rack control valve

Should removal of the rack control valve be required, it is advised that the rack be removed from the vehicle. This recommendation is made principally to minimize the entry of grit to either rack or control valve and also to eliminate damage to the control valve lower seal if the pinion is inserted in situ.

NOTE: Before refitting control valve to rack it is advised that the rack thrust button is first released of load.

Removing rack (Fig. 57.17)

1. Raise car on ramp or jack.

2. Remove pinch-bolt and nut from pinion shaft universal joint.

3. Clean control valve in vicinity of pipe unions.

4. Disconnect, at control valve housing, the main oil supply and return unions (flexible pipes).

5. Plug, or seal off, disconnected unions and control valve ports to prevent entry of grit.

6. Disconnect tie-rod ends from steering-arms.

7. Remove the four bolts, plain and spring washers, and angle plates securing rack mounting feet to mounting brackets.

8. Withdraw rack forward to release pinion shaft from universal joint and remove from car.

Replacing rack

1 . Centralize rack and position it on car.

2. With front road wheels and steering-wheel set in straight-ahead position, engage pinion shaft in steering shaft universal joint ensuring that the flat machined in pinion shaft corresponds with bolt location in universal joint.

3. Align tapped holes in rack feet with those in mounting brackets and engage single plates, bolts, plain and spring washers. Ensure single plates are in contact with mounting platform before tightening bolts.

4. Connect tie-rod ends to steering-arms.

5. Fit pinch-bolt to universal joint and pinion shaft.

6. Connect flexible pipe unions to control valve.

7. Top up hydraulic reservoir, bleed steering system and check for leaks.

8. Check also that the rack Bundy pipes do not make contact either with each other or any part of the car.

DATA

Hydraulic pump

Fluid capacity (including reservoir). . 1.75 Imp. pts. (0.995 litres) approx.

Pump delivery: Min... 1.04 Imp. g.p.m. (4.727 litres) at 170' F. at 465 r.p.m. against 665 to 735 p.s.i. (46.75 to

51.67 kg. /CM.2)

Max. 1.79 Imp. g.p.m. (8.138 litres) at 170' F. at

1,500 r.p.m. against 50 p.s.i. (3-515 kg./cm.')

Relief valve 750 p.s.i. (52.73 kg./cm .2) min., not exceeding

850 p.s.i. (59.76 kg./cm .2 ) at 1,500 r.p.m.

TORQUE FIGURES

Hydraulic pump

Pump reservoir to housing 35 lb. ft. (4-85 kg. in.)

Pump to mounting bracket 34 lb. ft. (4-84 kg. in.)

Pressure hose unions . . 25 lb. ft. (3-46 kg. m.)

Relief valve union 25 to 40 lb. ft. (3-46 to 5-53 kg.m.)

Control valve

Flange nuts 10 to 14 lb. ft. (1.38 to 1.94 kg. m.)

Unions-Bundy tubing 12 to 16 lb. ft. (1 .66 to 2.21 kg.m.)

Rack

Locknut-rack plunger 55 to 65 lb. ft. (7.6 to 8.99 kg.m.)

Slotted nut-cylinders and housing. . 80 to 90 lb. ft. (11.06 to 12.44 kg. m.)

Inner ball joint to adaptor 80 to 90 lb. ft. (11.06 to 12.44 kg.m.)

Adaptor-cylinder sleeve 25 to 29 lb. ft. (3.46 to 4.02 kg. m.)

Unions-Bundy tubing 12 to 16 lb. ft. (1.66 to 2.21 kg. m.)

Tie-rod-inner end 40 to 50 lb. ft. (5.53 to 6.92 kg. in.)