Classic cars forum & vehicle restoration.

[peter scott]

This was a repair I was not expecting. Over the 30 years I've had the SS I've only covered 30k miles. However, whenever I would leave the car unused for more than a 2 or 3 week period I would find that the clutch wouldn't disengage properly for the first mile or two and engaging first or reverse was not possible without holding the lever against second for a few seconds.

After getting it into first I would then slip the clutch for a few seconds as I assumed that corrosion on the flywheel face had locked it to the centre plate.

That was OK until this year when I found that applying much torque on hills was causing slippage.

Over the last couple of days I have been removing and refitting the gearbox to let me replace the centre plate and cover. It's a toss-up whether it's easier to take the engine out or take the gearbox out.

I really don't like taking the bonnet off and on single handed so the gearbox was my decision. Apart from the need to remove floorboards and two exhaust systems it also needs the propshaft disconnect at both ends.



I managed to remove the gearbox yesterday and today replaced the clutch and got the gearbox back in.

The old centre plate measured 0.350" as against 0.375" for the new plate. Much to my surprise there were no signs of corrosion on either the flywheel or the compression plate.

I still have quite few hours of reassembly work before I can discover the result but I'm fairly confident that the extra 25 thou will cure my slippage problem although it remains to be seen whether the new cover has cured the failure to disengage.

Peter.
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https://www.nostalgiatech.co.uk
1939 SS Jaguar 2 1/2 litre saloon

[bjacko]

Often caused by a fine trace of oil or grease like substance on the clutch plate faces. It can sometimes be removed by slipping the clutch and burning it off. Brakes can have the same problem.
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1938 Morris 8 Ser II Coupe Utility (Pickup)
1985 Rover SD1 VDP

[peter scott]

This could be a factor. My measurements of the clutch lining thickness differ from the actual specification that defines the individual lining thickness rather than the overall thickness.

The individual lining thickness spec is 0.145" to 0.155". This is more difficult to measure when the two layers are sandwiched together. My failed plate has thicknesses close to 0.145".

Here are the new and failed plates and covers without any wiping or cleaning. There may be a slight oiliness but certainly not a lot. Another factor may be the spring characteristics. The correct springs are cream colour whereas there is no obvious colour on the springs in the failed cover.



Peter
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https://www.nostalgiatech.co.uk
1939 SS Jaguar 2 1/2 litre saloon

[Ray White]

I would have said the springs are the problem. If it was the clutch lining I guess you would have smelt it burning.?

Having said that it does look to have an oily sheen look about it.

[alastairq]

I agree re-the springs.

I wonder if you could insert two pence pieces under the springs, or some of the springs, to increase their rate a bit?
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Dellow Mk2, 1951 built, reg 1952.
Fiat 126 BIS
Cannon special [1996 registered. Built in 1950's]
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Ford Pop chassis, Ashley 1172 bodyshell, in pieces.

[peter scott]

Horror of horrors! That would have cost me a further 18p. I am a Scotsman you know.

I still have a few hours of work to refitting floor boards, carpets and the front passenger seat not to mention my reversing camera display but I drove her out of the garage and a few yards down my drive this afternoon and the new clutch felt very nice with progressive engagement and full disengagement. Quite a relief.

Peter
_________________
https://www.nostalgiatech.co.uk
1939 SS Jaguar 2 1/2 litre saloon

[Ray White]

Well done, Peter.

[Brent29]

[norustplease]

[alastairq]