Clutch Problems

Is this you?

"I’ve fitted a new clutch this weekend and now its not releasing or its releasing right at the bottom of its travel, is the new clutch faulty?

The short answer is there is probably nothing wrong with the new parts fitted but fitting it has brought to light other problems that were masked by the previously fitted worn out components.

The easiest place to start looking on the Herald, Spitfire, Vitesse and GT6 range of cars is at the clutch pedal itself. Physically grab hold of the clutch pedal and move it backwards and forwards in the free range before any hydraulic pressure is felt. If this free range is any more than ½ inch at the pedal rubber end of the lever then you have problems.

Lost mechanical movement manifests itself in many ways, here are a few;

The first place to look is in the clevis pin, master cylinder pushrod fork and clutch pedal area. Pull back the master cylinder boot and have a look. Its not unusual to find the clevis pin worn to half its normal diameter and the fork holes and clutch pedal holes worn to twice their diameter (shown as elongated holes). If this is the case then you are probably losing a massive amount of movement at the other end of the lever, anything up to 3 inches.

The clevis pin is easily sorted, buy a new one (fit a new split pin at the same time) they are very cheap.

On a regularly used car (as they all should be!) you may have to change this every 4 or 5 years. The fork and pedal holes are not so easily sorted, in our workshops we salvage these by removing both from the car and welding 5/16 washers to the fork holes and welding the pedal hole up and re drilling it to 5/16. You may find it easier to fit better second hand components or exchange maybe.

When refitting the clutch pedal use plenty of copper grease on the pivot pin (secured by a circlip at either end) as its not unusual to find this partially seized as well. When reassembling the fork, clevis pin and pedal also use plenty of grease and be prepared to re grease at least once a year. Imagine how many times these components work against each other in the average journey and you see the enormity of the problem!

The next area in which to look is the hydraulic side of the system, if it hasn’t been overhauled in the last 6 or 7 years its probably well past its best.

Fitting a new clutch driven plate means the slave cylinder pushrod will have been disturbed and is now operating in a different area of the cylinder. This means the piston seal is now rubbing over previously undisturbed corrosion, crystallised brake fluid and other nasties.

On the six cylinder cars it’s quite easy to check, pull back the dust cover and have a look how horrible it is.

The four cylinder cars are not so easy because they have the peaned over steal dust cover retainers, but if you are careful you can take these off and re use them peaning them over in a similar fashion. They are both simple and inexpensive to rebuild with cheap seal kits available for both.

Thoroughly clean out checking for any deep scratches or scoring which renders the cylinder scrap, and rebuild with new seals using brake fluid as a lubricant. Similar recommendations apply to the clutch master cylinder.

On rare occasions you may find the conical shaped spring inside the cylinder broken. When cleaning out the cylinder prior to resealing, check the flat face at the bottom of the cylinder is clean and free of bits of stuck rubber etc.

On the four cylinder cars another problem area is the release bearing carrier arm. If you are fitting a new clutch then you will be fitting a new release bearing, which means you will have removed the arm from the bellhousing. At this point you should as a matter of course replace the two bronze bushes, tolerance ring (crinky washer), and pivot pin, part numbers; 129358 x2, 129412, and 129410.

In the aluminium arm assembly are two pivoting steel bushes which the bearing thwowout sleeve is allowed to spin in. These steel bushes can seize giving the effect of a stiff pedal and a poorly releasing clutch and as a result rapidly wearing parts elsewhere.

These bushes can be unseized using WD 40 or similar and a bit of persuasion, beware they only normally swivel over a small range limited by the steel pins holding them in place. On the six cylinder cars the bearing arm is a different arrangement giving different problems arising.

Things to look for here include checking where the arm pivots on the steel soldier fitted in the bellhousing. Any cracking here can give problems. Also the steel pins in the arm can wear where they push on the throwout sleeve, the only real solution in either case is a replacement clutch release arm.

One engine problem that can feel like clutch release problems is the dreaded crank thrust washers falling out. Get a friend to watch the crank pulley as you push the clutch pedal in and out, if it moves more than a gnats knacker you have big bills looming (see our engine technical pages).

When you rebuild your hydraulics it’s a good idea to refill the system with silicon fluid as its not hydroscopic and this delays the onset of corrosion in the system specially during periods of inactivity, winter lay-ups etc