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Clutch

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davidtinker

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OK its 31 posts in 6 years but whose counting!!

A problem I thought I had solved has come back to haunt me. Briefly when putting the gearlever into first there was some resistance felt and on occasions it was necessary to move back to neutral let the clutch out and try to engage first gear again. Similarly on selecting reverse there would be a grating of teeth before engagement.But not everytime.
Initially I wanted to replace the seals in the Clutch Master cyl but was told they were no longer available. So I bought a new CMC which was not the same as the original but had the same mounting flange but a shorter piston travel. I was told by David Manners Ltd that this is what was being supplied now so I went ahead and fitted it. Result no difference!!. So then I managed to find a rebuild kit for my original CMC (which I had re-sleeved with a stainless liner some years ago) result no difference!

Then bought and fitted a new CM slave cylinder of the type without a return spring. Result no difference!.

So then put back the replacement non standard CMC and after a long session of bleeding the system success!! or so I thought.

Today I took the car out to a car show which entailed a drive of 40 miles there and 40 back. Experienced a difficulty in selecting first when pausing at roundabouts and at my destination more crunching of gear teeth when selecting reverse.

But on the return journey having arrived back home and manoevring into the garage, selecting reverse achieved no drive until the clutch pedal was almost at the limit of its travel, suggesting that the clutch was not being released!

The only part that I have not replaced is the flexible hose between the body mounting bracket and the engine mounting bracket.

Prior to making all these changes of components I had reverted from Silicone Fluid to DOT4 as I thought that DOT 4 has better lubricating properties that Silicon. However I still use Silicon fluid in my braking system with a problem.

Thats the story so far! Has anyone any bright ideas as to what the problem might be and its solution.

Cheers,

David
 
Hi Guys, I have just spotted an error in my post. I said that I was still using Silicone fluid in my braking system with a problem!! it should have read 'without a problem'
Cheers
David
 
Sounds like either the clutch is not disengaging completely... and or... the 1st gear synchros are gone. /ubbthreads/images/graemlins/confused.gif But I'm not a knowledgeable jaguar guy, and I don't even know what model your talking of here. I do know on My MGB, that 1st and reverse will crunch gears a bit sometimes... 1st especially if I'm not completely stopped yet (even just barely rolling).

You could also have a problem with there still being some silicone fluid in the system????? Since you changed to Dot4 again... As I've read - they are no where's close to compatible with each other... changing might have induced a problem?
 
If you have not replaced the flexible hose attached to the clutch slave cylinder in several years or after changing back to DOT 4, it is possible the hose inner lining has ruptured and allowing fluid to enter the outer jacket. It is my recollection that standard clutch hoses have no reinforcement such as stainless steel braid around the outer jacket, so it could be the hose baloons up and the slave cylinder receives insufficient pressure to operate the clutch. I don't know if switching from silicon fluid would cause the hose to deteriorate. If you did not rebuild the slave cylinder when you changed fluids, you should now, due to the incompatibility of the two fluids.

Take a look at your flexible hose and see if it has any soft spots. Good luck.
 
Hello David,

being a manual Jaguar, MK 2 or E Type?, the flexible hose is the primary suspect and also any free play adjustment?
Don't worry about mixing silicone brake fluid with Dot 4, the UK brands manufacturers say they are compatible. I'm interested in the comment that the new slave has reduced stroke, as the stroke is proportional to the bore as the MC displaces x volume and the slave stroke is a simple volume\bore displacement calculation.

Alec
 
Hi Alec, thanks for your comments, actually it is the replacement Clutch MS which has the reduced stroke, but sometimes it works other times it does not!!
Rogers,You are correct in that the standard clutch hose has no reinforcement, as I removed it this evening and was hoping to find some of the symtoms you suggest. Alas all looked well but I will order a replacement tomorrow.
Kenny, I agree with you that the clutch is not disengaging completely but I hope it is an hydraulics problem rather than the syncros. I renewed these when the g/box was rebuilt 10k miles ago. But if all else fails I will have to take the engine out again!!

I should have said in my initial post that we are talking about an S1 2+2 4.2l 1966 car and also that the fluid was changed from Silicone to Dot 4 prior to any of the cylinders being replaced.

Thanks to you all,

David
 
Before buying any more replacement parts, ask someone to depress the clutch pedal while you look at the slave cylinder. If the stroke is normal (my recollection is not more than an inch), then a possible suspect might be your throwout bearing or the clutch driven plate.

If the bearing is worn down, it won't move the clutch levers far enough to disengage the clutch driven plate from the flywheel and pressure plate completely.

A worn throwout bearing could account for the drag you feel in low and reverse. Probably the syncros in the other gears are masking this symption. If you continue to drive the car, it won't be long before you can't shift gears at all.

Another way of checking for a dragging clutch is to jack up one rear wheel if standard differential or both rear wheels if limited slip, have an assistant hold the clutch down while in any gear and try to turn the rear wheel. It should turn without much effort. If does not, it is likely the clutch is not fully releasing.

Armed with this information, you can then take the car to a mechanic for his or her diagnosis and see if it corresponds with your own.
 
Hello David,

sorry, I misread the original post. Let's see what the new flexible hose does, but most certainly your original is fabric reinforced, the system would not work otherwise as the hose would balloon and reduce the effective pressure to the slave. Do check the clutch free play even if it is not adjustable (I have a MK2 but can't remember if it is adjustable or not) and if it is significant (more than about 1\8") that wants looking at.

Alec
 
Thanks to everybody who responded to my clutch problem. Rogers & Alec I removed the flexihose and did an autopsy on it!! Slitting it down its length it looked fine with no ruptures. Then I cut the hose across the tube flush with the metal couplings. The hole was so small that I could only just insert a 1.5mm drill into it.

A new hose and the problem seems to have been solved. I could have avoided the expence of a new clutch master clyinder and slave cylinder.

My Father always used to say ' aproach a problem using the KISS principle'. Keep it simple stupid.

Thanks again,
David
 
Yep... but the simple solution isn't necesarilly always the easiest task to accomplish, grasshopper. /ubbthreads/images/graemlins/grin.gif
 
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