E1

GENERAL

The clutch assemblies are of the single dry plate type  8,5 in. (215,9 mm) diameter. 

The clutch disc incorporates a spring-cushioned hub; the woven asbestos linings are flexibly mounted to ensure a smooth take-up of the drive. The clutch disc hub is free to slide along the splines of the main drive gear, the forward end of which forms a spigot to fit into the clutch pilot bearing in the centre of the flywheel. The clutch cover, springs, clutch release mechanism and pressure plate are serviced as an assembly. 

At the release finger pivot points there is only rolling contact, sliding friction is eliminated. 

The clutch release mechanism is hydraulically actuated by means of a pendant pedal mounted beneath the instrument panel, controlling the clutch master cylinder. A pipeline and flexible hose connects the master cylinder to the operating cylinder mounted on the clutch housing and retained by means of a circlip. Any possibility of irregular clutch engagement caused by movement of the engine, clutch and gearbox unit in relation to the clutch pedal is  therefore eliminated.

Maintenance

The clutch fluid reservoir is integral with the clutch master cylinder and the level should be checked every 1,000 miles. Top-up with genuine brake fluid to the level marked on the outside of the reservoir casing (see Fig. E.3), which is approximately 1 in. (16 mm.) from the top. The cap and reservoir should be wiped with a clean rag before removing the cap to ensure that no dirt or foreign matter enters the system. Make sure that the vent is clear before replacing cap. The only other attentions which may be required by the clutch mechanism are the adjustments described as follows:

E2

CLUTCH ADJUSTMENTS

When the clutch mechanism is correctly adjusted the following conditions apply:

1.    Just perceptible clearance between the pedal push rod and master cylinder piston.

2.    1/16 in. (1,6 mm.) clearance between the clutch release arm and the operating cylinder push rod.
The pedal returns to its stop without hesitation. The adjustments can all be quickly checked at the clutch pedal. Very slight movement of the pedal should be sufficient to take up the initial clearance between push rod and master cylinder piston. If the clearance at the operating cylinder is correct there will be approximately 1 in. (25,4 mm.) free travel before the clutch begins to be released. Full instructions concerning the adjustment procedure appear hereafter.

E3

PEDAL ADJUSTMENT

The pendant clutch pedal is linked to the master cylinder piston with an adjustable push-rod, with clevis attachment to the pedal shank. 

The push-rod has an adjustment nut with lock nut and these are positioned and locked together to correct pedal travel, as necessary. The pedal pad is also adjustable, at its mounting point at the foot of the pedal shank. 

The clearance between the clutch release arm and operating cylinder push rod should normally be 1/16 in. (1,6 mm.), although on a new car or after a new clutch disc has been fitted, the clearance should be increased to 1/10 in. (2,7 mm.).  Should the clearance at this point be reduced, it is possible for the clutch release bearing to be in permanent contact with the clutch-fingers, causing unnecessary wear and possibly clutch slip.

To effect the adjustment, disconnect the retracting spring, slacken the lock nut and turn the domed adjusting nut until the correct clearance is obtained between the end of the release arm and the nut. Tighten the lock nut securely, recheck the adjustment and reconnect the retracting spring.

E4

THE CLUTCH OPERATING CYLINDER

The clutch operating cylinder is mounted in the flange of the clutch housing on the right-hand side and is held in place by a circlip. 

To Remove

1.    Disconnect the retracting spring.

2.    Using a pair of circlip pliers, remove the retaining circlip.

3.    Withdraw the cylinder assembly forwards complete with push rod.

4.    Remove the push rod and the dust excluding rubber cap. Gently depress the clutch pedal to push the piston and seal out of the cylinder.

5.    Disconnect the flexible hose and fit a blanking plug to the hose to prevent fluid loss. 

Note.-Should it be necessary to remove the cylinder complete without dismantling it as described, a pump applied at the fluid union can be used to push the piston and piston seal from the cylinder.

To Dismantle

1.    Remove the bleed valve from the cylinder.

2.    Pull the rubber piston seal off the spigot at the front of the piston.
Wash all parts in the correct hydraulic fluid, methylated spirits or commercial alcohol and examine the rubber piston seal carefully. Renew the seal if there is any sign

of damage to the sealing lip. Never use mineral fluids such as engine oil or paraffin for washing hydraulic system parts.

To Reassemble

1.    Locate the piston seal on the spigot at the front end of the piston so that the sealing lip is away from the body of the piston.

2.    Dip the piston and seal in hydraulic fluid and carefully insert, spigot end first, into the cylinder.

3.    Refit the rubber cover over the end of the cylinder.

4.    Replace the bleed valve in the upper of the two unions but do not tighten.

To Replace

1.    Remove the blanking plug from the end of the flexible hose and reconnect the hose to the cylinder.

2.    Replace the push rod and slide the cylinder into its location on the clutch housing flange from the front. Replace the circlip and ensure that it locates correctly in its groove. 

3.    Bleed the hydraulic system as described on page M.6. 

4.    Adjust the clearance between the domed nut on the operating cylinder push rod and the clutch release arm as described previously. 

E5

THE CLUTCH MASTER CYLINDER

The clutch master cylinder is mounted on the engine bulkhead and is bolted to the front flange of the pedal assembly bracket.

The front spigot end of the piston accommodates the valve stem and carries the return spring retainer. The return spring (under compression) is fitted between the spring retainer and valve spacer at the forward end of the cylinder (see Fig. E.3). A valve seal is fitted to the forward end of the valve stem. From approximate engine Nos. 204E-140540 and 206E-132253, an improved type of seal incorporating an annular ring moulded on its outside periphery is fitted.

This modified seal should be fitted in place of the previous plain seal if a replacement is required in service.

A reservoir port drilled at the front of the cylinder allows fluid from the integral reservoir to enter the cylinder. The pipe line to the clutch operating cylinder leaves the master cylinder at a port immediately behind the reservoir. When the clutch pedal is in the fully released position, fluid is free to flow from the reservoir into the cylinder. When the pedal is depressed the piston moves forward and closes the valve to prevent the fluid being pumped back into the reservoir. The fluid is therefore pumped through the outlet port to the operating cylinder on the clutch housing. When the pedal is once again released the return spring pushes back the piston, reducing pressure in the cylinder, and the release arm retracting spring acting on the operating cylinder piston pushes the fluid back into the master cylinder. The valve uncovers the reservoir port so that fluid may be replenisbed in the cylinder as necessary.

 A rubber cap fits over the end of the master cylinder and fits closely around the push rod to prevent the entry of dirt into the cylinder.

The clearance between the push rod and the piston on the cylinder is pre-set and the piston cannot be prevented by the push rod from returning to its full extent.

E6

THE PEDAL ASSEMBLY

The clutch pedal is of the pendant type, secured at its top by a pivot bolt and connected to the master cylinder with an adjustable push-rod. 

To Remove

1.    Remove the clevis pin which connects the push rod clevis to the speclal shank.

2.    Release loading spring.

3.    Remove the top pedal pivot bolt and anti-rattle spring.

4.    The assembly may now be manoeuvred downwards, and freed. Reverse this procedure to refit, taking care to replace the anti-rattle spring.

 To Remove the Master Cylinder

1.    Remove the clutch shank clevis pin from the push-rod.

2.    Disconnect the hydraulic pipe union from the cylinder body.

3.    Remove the two bolts securing the cylinder body to the rear engine bulkhead.

4.    Remove cylinder complete with push rod, and drain. Reverse procedure to refit, taking care to re-set the pedal adjustment to give 'just perceptible' movement before engaging the master cylinder piston stroke.

E7

OVERHAULING THE CLUTCH AND RELEASE MECHANISM

To gain access to the clutch, the gearbox or engine must first be removed.

1. To remove the clutch disc and pressure plate assembly, slacken the six securing screws evenly and detach the assembly. Inspect the clutch disc and check that the linings are not loose and are free from oil. The discs should also be checked for excessive wear or signs of overheating. Replace the disc if the linings are worn down near to the rivet heads, or if any of these conditions are apparent. Check the condition of the surface of the pressure plate and the compression springs. Should any sign of scoring, overheating or distortion be present, change the assembly.
   Depress each clutch finger in turn and release it slowly to check the action of the release mechanism. Fig. E.4 illustrates the type of release mechanism fitted; the anti-friction pivot for the clutch fingers and the pivot plates are clearly shown.
   The clutch pilot bearing located in the centre of the flywheel is a ball race. The bearing is packed with lubricant on assembly and does not require lubrication in service.

2. To remove the clutch pilot bearing from the flywheel engage the legs of the puller. CPT.7600-3, behind the bearing and tighten the nut on the centre bolt to extract it. Alternatively, if the puller is not available, the bearing may be driven from its mounting after removing the flywheel, using the driver. Wash the bearing thoroughly in petrol or paraffin and check for signs of wear.

3. Replace the clutch pilot bearing using tool No. CPT. 7061. Care must be taken to locate the sintered bronze pilot bearing correctly in the flywheel with the flat face of the bearing towards the engine and the shouldered face towards the clutch disc. If the bearing is of the early ball bearing type, it must be repacked with a suitable high melting point grease and then fitted with the shielded face towards the clutch disc and the open side towards the crankshaft.

4. Place the clutch disc in position on the flywheel face with the longer shoulder at the hub towards the gearbox. Align the disc with the pilot bearing, using locator P.7059. 

5. Refit the pressure plate assembly. Replace the six securing screws and spring washers, tightening them evenly. Remove the clutch disc locator.

6. To remove the clutch release bearing, disconnect the retracting spring, remove the spring clip securing the rubber gaiter to the release arm and detach the gaiter. Pull the forked end of the release arm out of the spring clips at the rear of the bearing hub and disengage the arm from the fulcrum pin. Pull the hub and bearing off the main drive gear bearing retainer and withdraw the release arm. 

7.    To dismantle the clutch release bearing assembly, hold it with the bearing downwards and tap the shoulder of the hub sharply on the bench.

8.    Reassemble the clutch release bearing. Check that the release arm fork spring clips on the rear face of the hub (illustrated in Fig. E.1) are in good condition and assemble the new bearing on the hub with the thrust     face of the bearing away from the hub. Suitably support the bearing on the bed of a press, leaving sufficient clearance for the shouldered end of the hub to protrude. Press the hub into position, ensuring that it enters     squarely into the bearing bore.

9.    Pass the clutch release arm through the aperture at the side of the clutch housing, with the fulcrum pin spring clips, shown in Fig. E.1, facing towards the rear. Engage the clips around the fulcrum pin load.

10.Check the machined sleeve of the gearbox main drive gear bearing retainer for burrs. etc., lightly smear the sleeve with high melting point grease and replace the release bearing assembly, engaging the forked end of     the release arm in the spring clips on the hub. Check that movement on the outer end of the release arm is freely transmitted to the bearing. Refit the rubber gaiter to the clutch release arm.

11.Replace the gearbox or engine whichever has been removed.

E8

THE CLUTCH RELEASE BEARING

Care must be taken during service, that the correct clutch release bearing hub is fitted. Clutch release bearing hub Part No. EOA-7561 differs from the hub Part No. 204E-7561 by the length of the machined surface from the front face of the hub to the shoulder which abuts the rear of the release bearing.
If the bearing hub, Part No. 204E-7561 is erroneously fitted in placc of the hub, Part No. EOA-7561 the release bearing will be located too far forward on the hub, and may, when the clutch is depressed, cause the clutch fingers to foul the clutch disc.
For ready identification, the length of the machined surface referred to above and the corresponding gap between the front face of the hub flange and the rear face of the bearing when correctly located, are tabulated in the 'Specifications'. The release bearing is of the pre-lubricated type and should require little attention in service.

1.        Remove the gearbox assembly as described in section C. Where a rubber gaiter is fitted on the clutch release arm, detach the outer clip and pull the gaiter off the arm.

2.        Pull the forked end of the release arm out of the spring clips at the rear of the bearing hub and disengage the arm from the fulcrum pin. Pull the hub and bearing off the main drive gear bearing retainer.

3. Hold the release bearing assembly with the bearing downwards and tap the shoulder of the hub sharply on the bench, when the bearing can be removed from the hub. 

To Replace

1. Check that the spring clips on the rear face of the hub are in good condition and assemble the bearing to the hub with the flat face of the bearing away from the hub shoulder.

2. Suitably support the bearing on the bed of a press, leaving sufficient clearance for the shouldered end of the hub to protrude.

3. Press the hub as far as the shoulder, ensuring that it enters squarely into the bearing bore. 

4. Pass the clutch release through the aperture at the side of the clutch housing, with the spring clips to the rear. Engage the clips at the lower end of the arm around the fulcrum pin head. 

5. Check the machined sleeve of the main drive gear bearing retainer for burrs, etc. Pack the pocket at the rear of the hub with high melting point grease and replace the release bearing, engaging the forked end of the release arm in the spring clips on the hub. Check that the hub moves freely on the main drive gear bearing retainer and that movement of the outer end of the release arm is freely transmitted to the bearing. 

6. When fitting the clutch release arm gaiter, locate the square wire clip in the larger diameter of the gaiter, and position it on the release arm, larger end first, so that the end of the gaiter fits inside the aperture in the housing (see Fig. E.1). (It is essential that the edges of the aperture are free from burrs and sharp corners). Fit the smaller clip around the outer end of the gaiter and push the gaiter up the arm until the cut-out in the end of the gaiter fits round the depression in the release arm and clears,the push rod adjusting nut. 

7. Replace the gearbox assembly as described in section C. 

E9

THE CLUTCH PILOT BEARING

This bearing serves as a mounting for the forward end of the main drive gear and only rotates relative to the main drive gear when the clutch pedal is depressed.

The bearing is of the sintered bronze type and it is most important that it is fitted square in its bore in the flywheel with the shouldered face towards the engine and the flat face towards the clutch.

Alternatively, a ball type clutch pilot bearing (B-7600-A) is available for service only, together with a 0,004 in. (0,10 mm.) oversize ball bearing.

A noise, audible when the clutch is fully depressed, does not necessarily indicate that the pilot bearing is at fault, since the clutch release bearing itself is also rotating on the hub under these conditions. In the event of a noise associated with either the clutch release bearing or the pilot bearing, the following test will enable the sound to be located.

Press down the clutch pedal with sufficient pressure to cause the release bearing to rotate without freeing the clutch. If the sound is then heard, the noise is definitely associated with the release bearing. If the noise increases when the clutch is fully depressed, then the additional noise may be due to a worn pilot bearing in which case it should be replaced. 

To Remove 

1.    Remove the gearbox assembly as described in the 'Gearbox' section. 

2.    Remove the clutch disc and pressure plate as described on page E.4. 

3.    Withdraw the bearing from the flywheel, using Tool No. AT3/U7600-A. If the pilot bearing is being removed from the flywheel on the bench, the driver    AT/U7600-B may be used to press the bearing from its flywheel location.

To Replace

1        Locate the new pilot bearing in its location with the flat face of the bearing towards the clutch disc and the shouldered face towards the engine.

2        Tap the bearing into place. using the driver AT/U 7600-B, ensuring that it is fitted square in its bore. This latter point is most important, as an incorrectly fitted bearing will quickly wear and cause clutch noise and vibration.  

3        Replace the clutch disc and pressure plate assembly as described on page E.4.  

4        Replace the gearbox as described in section C. 

E10

SPECIFICATIONS AND REPAIR DATA 

Clutch disc linings:
Outside dia.              8,5 in. (203,2 mm.)
Inside dia.                5,75 in. (146,0 mm.)
Thickness                 0,16 in. (3,86 mm.)
Number of springs in clutch hub:         6 - Green 

Pressure plate: 
Outside dia.             8,64 in. (219,5 mm.)
Thickness                0,47 in. (11,94 mm.) 

Pressure springs:    6 - brown with blue paint mark 
Spring Pressure:   189-199 lbs. (85,73->90,3 kg.) at compressed length of 1,6 in. (40,84 mm.)