Clutch problems

[Crockett]

Hi,

Following on from my earlier posts regarding the clutch master cylinder spring etc.), I have now successfully repaired both the master and slave cylinders and bled the system but I am still having some problems getting into gear.

This seems to be intermittent, i.e. sometimes it will go into gear first time and sometimes it wont. Once it is in gear, I can continue to hold the clutch pedal down and the clutch no longer starts to engage, causing the car to creep forward (which it what it was doind before I repeaired the cylinders, which were both leaking).

One thing I have noticed is that if I lift my foot off the clutch slightly, so that the car starts to move forward and then press the clutch pedal fully down again, it is very difficult to get the car out of gear again and impossible to then get it back into gear without releasing the clutch and depressing it again.

Even then it may no want to go into gear until after 3-4 attempts at releasing and depressing the pedal. The problem is most noticeable when trying to engage reverse. The gears sometimes crash and grind but at other times slip in easily. When I lift the pedal slightly, so that the car starts to move,  then press the pedal hard down again, getting out of reverse is difficult and it's impossible to get back into reverse, as the gears grind.

Something I did notive though, was that when I was reconnecting the master cylinder I noticed that the clutch pedal was hanging loose. I checked the manual and there should be a pedal return spring to pull the pedal up. Further investigation revealed that this spring was broken.

I wonder if this could be the cause of this intermittent clutch problem. I guess it's possible as the pedal is effectively being returned by the master cylinder spring.and hydraulic pressure generated by the spring in the slave cylinder and the clutch diaphragm. So the master cylinder piston may not be returning as far or as quickly as it should?

I also wonder if this may have been involved in the spring in the master cylinder, and the seals in both cylinders, failing in the first place as it means that there will have been some pressure (the weight of the pedal) on the clutch mechanism at most times?

Regards.
Daryl

[heraldcoupe]

I've no doubt that the broken pedal spring is what caused the failure of your master cylinder spring. I have seen this so many times, the master cylinder spring has to work so much harder than it was designed to.
I have to say that your current symptoms still describe to me a system with some air remaining. The wide bore plastic pipe in the 2000's clutch hydraulics wkes bleeding difficult. Surface tension allows bubbles of air to cling to the side of the pipe, the fluid moves past them, you will still see clean bubble free fluid being bled. This doesn't happen so easily with the fine bore tube in the smaller cars, but I have found both Dolomite and 2000 troublesome because of the big pipe. On a Dolomite I once had to resort to holding the slave cylinder at a higher point than the master while bleeding. The slave and pipe were then threaded down into the engine bay and bolted back in place. I'm not sure how easily this can be done on the 2000 as I fixed ours before reaching this step. Our symptoms were identical to yours,
Cheers,
Bill.

[valencia1]

could be the clutch over centreing when operated  but before taking the gearbox out make sure
the clevis pins and holes are not worn/oval. what dia. slave cyl. do you have? you could try a try a7/8 bore one to give you more travel of the push rod.
has the clutch set ever been replaced that you know of? apart from a worn set of clutch parts
another possible problem is the cross shaft pin that  holds the thrust bearing carrier may be
broke/worn.

[Doig]

I had similar problems to this recently after fitting a new clutch and gearbox. I would agree with valencia1 and fit a 7/8 bore slave cylinder. Before this i had the master cylinder rebuilt and that broken spring replaced (This is a good reminder to everybody to check their's are still working before bigger problems arrive)

All working fine now thank god.

PS don't discount the obvious are any of the car matts or carpet obstructing the travel of the clutch pedal (this could explain the intermittant nature of the problem)

[Deleted User]

I take it you would have had a chance to check the seals and that the cylinder wasn't scored when it was apart. sounds to me as though you either have still got air in the system or the mater cylinder isn't returning properly. Since you said you had a broken pedal spring, I suspect that is the problem.You'll only have the pressure of the fluid returning the pedal. If the cylinder falls only slightly short of its rest position it cant take any more from the resevoir.

[Crockett]

Hi,

Thanks for all the replies, they have certainly given me food for thought.

To answer one or two points.

I checked both the master and slave cylinders and neither appeared to be scored. The master cylinder spring was bent when I disassembled the mecahnism and broke in my hand shortly afterwards, so it wasn't actually broken while it was in place. I discovered that it had become extremely brittle and had basically split in two at various points along its length.

It's true that the floor mat is a bit troublesome and does occasionally fall down to foul the clutch pedal. It's possible that this in conjuntion with the broken pedal spring might be causing problems. I'll make sure the carpet is better secured.

I'm not sure if the clutch has ever been replaced. It hasn't since I've had the car. The clutch doesn't slip but I'm left wondering if the plate is perhaps sticking on the splined shaft a little.

The slave cylinder is a 7/8" bore. None of the clevis pins look to be worn.

One question that I had was, there appear to be three positions in the arm for attaching the slave cylinder to. At the moment it's in the middle one but it looks like it could connect to either of the other two. I guess this makes a difference to how heavy the clutch is versus how far the clutch clears but I'm not sure.  Does anyone know what difference selecting another hole might make, before I try it?

It seems to me that there a lot of small problems that need correcting, any of which could be causing this problem but certainly a combination of all of them almost certainly could.

I think what I'll do first is to replace the pedal return spring and fix the carpet. These obviously need doing anyway and it's a good starting point.

If I still have problems then I'll take another look at whether there might be any more air in the system, bleeding it with the slave out of position and raised as required. Replacing that somewhat troublesome plastic pipe with a braided steel type is also perhaps an option.

I'll post any results as these will no doubt be useful to anyone else who experiences similar problems. Maybe I should have bought an automatic :)

Thanks again for the advice.

Regards
Daryl

[Richard B]

Which of the three holes to use depends on which car: 2000, 2.5, Stag, TR or Sprint. The cross-shaft is common to all. I cannot remember which hole is for which car though. The workshop manual should list the correct one.

The highest hole will give you the most clutch travel, but a heavier pedal.

The other area to check is the cross-shaft bushes in the bell housing; wear in either the cross-shaft or the bushes will show up as sideways movement in the cross-shaft.

7/8" is correct for a 2000, the 2.5 had the 1" slave cylinder.

[Crockett]

I replaced the pedal spring and it helped the situation considerably but there was still occasionally a problem with getting into gear.

Just to see what would happen, I tried moving the slave cylinder's push rod to each of the other two holes. I could find nothing in the manual that said which hole was the correct one.

I tried the top hole first, figuring that this would make the clutch heavier but might give more clutch clearance (as confirmed by some of the other posts here). The clutch pedal didn't reaIly feel all that much heavier but I was surprised to find that this actually made the problem even worse, with me only being able to get into gear occasionally.

So, I tried the bottom hole. This made the clutch noticeably lighter but also (for some reason) seemed to get rid of the problem with getting into gear. I'm not sure why but it appears to be much better than it ever has been.

I really have no idea why moving the push rod to the other two holes, gave the opposite results to those that I expected.

The only possibility I can think of is that there is some more air in the system somewhere and that the bottom hole causes any air bubbles to be compressed slightly less and therefore have less effect. This is a wild guess however.

I think I'll end up replacing the plastic hose anyway as I know they can cause trouble and be harder to bleed.

Regards
Daryl.

[Tim Bancroft]

Daryl,

Look back at previous threads on bleeding the hydraulics- always a problem- I got mine done by using an ezzi-bleed and running it at about 30psi- far in excess of the recommended pressure.

[aaron77]

Have you thought about the thrust bearing?

[Crockett]

Hi,

I did wonder about the thrust bearing but given the intermittent nature of the problem and particularly the fact that things seem to be better with the slave cylinder pushrod in the borrom hole, I am still suspicious that there is a loss of pressure somewhere, perhaps due to air in the plastic pipe or even the plastic pipe warping under load..

The replacement stainless steel braided hose has arrived so I will fit that this evening and pressure bleed the system again.This should then eliminate the possibility of any pressure loss due to air or the pipe itself.

If this still doesn't solve the problem then it looks like I may need to dismantle the clutch to see if there is anything going wrong in there.

Regards
Daryl

[Crockett]

Hi,

Something annoying but interesting happened recently, related to the problem I have been having (described in my previous posts) with clutch-spin.

The car drove around fine for a few weeks, leaving me to believe that I had solved the original problem, but then recently, when trying to park it, the old problem came back again and I was unable to get into any gears due to clutch-spin.

I checked all the hydraulics and noticed a small fluid leak on the slave cylinder union (the master cylinder reservoir was still pretty full). I tried to get this to seal again and bled the system once more, using the Eezibleed kit. Unfortunately there was still a small leak on the slave cylinder union but to my surprise, I was then able to get into gear once again, even though I had effectively corrected nothing.

It seems to me that this problem now goes away each time I bleed the clutch and I have a couple of theories about the reasons for this:

1. The slight leak in the union is also allowing a small amount of air to enter the hydraulic system, when I lift my foot off the clutch, which then builds up to a level that causes problems. This seems unlikely but I suppose is possible? This may explain why bleeding the system corrects the problem each time (for a while). It's also unlikely as this leak has only happened since I fitted a stainless steel braided clutch hose. The original plastic hose didn't leak but I still had the clutch-spin problems.

2. The master cylinder (which had a broken piston return spring which I replaced and then repaired) is scored and the piston is sticking during it's return, so it is not compressing the correct amount of fluid. The 25psi of thee Eezibleed kit may be forcing the piston to return and work properly for a while, until it sticks once again. This may also explain why bleeding the system corrects the problem (for a while). I didn't notice any scoring of the cylinder (although it's quite hard to see properly) but I did notice that the piston wasn't as eager to return during testing it as I had expected.

Anyone have any thoughts on either of the above?

[Doig]

I had similar problems that were solved by the 7/8th slave for a while.

My problem was related to the clutch pressure plate being defective, also the actuating mechanism was worn and needed to be replaced.

The extra push of the 7/8th slave cleared the clutch for a few months but the pressure gave out in a big way after a long trip with a bitof heat. After that it continued to work when cold but after 5mins or so it was imposible to change gear. I suspect that where your problems lie

[Crockett]

Hi,

I already have a 7/8th slave cylinder fitted. Your comments about the pressure plate being worn is interesting though. Was this causing intermittent problems? There does not appear to be any play in the cross-shaft or any of the external linkage but who knows about the internals of the clutch?

In my case the problems don't appear to be related to heat, as I haven't noticed the problem being any worse after a long drive or any better when the car is cold and has not been run for a while.

Something that may be significant was that I did once get the problem after a long drive, when I was putting the car back into the garage. When I came to take the car out again a week later, the problem was still there. So it really would seem to be a problem that once their, remains until the system is bled once again.

I can't see why bleeding the hydraulic system should make any difference if the fault is in the clutch itself, though. I think what I may do is to replace the master cylinder (as I am still very suspicious of that) and then, if that doesn't work, consider replacing the clutch itself.

I do have a new clutch kit. The problem there will be finding the space to actually do the job. The garage that I have is extremely limited for space (the car only just fits). The other alternative of course would be to take the parts to a local garage and pay for the labour.

[Roger]

I recently changed the engine in a 2500 estate for a club member & he had complained of the same problem as you , on removing the engine I found that the fingers on the pressure plate were the release bearing sitshad worn down to a third of their original thickness.It looked like someone had been rideing the clutch. A new clutch was fitted & problem solved.