Clutch not quite disengaging...

[Ade-TR4]

Any news?

I think we all want to see this one to it's (successful) conclusion!

[littlejim]

Do you have the old bits that worked to compare with the new parts thickness wise?

Some years ago a kind friend with contacts in the trade got me a replacement clutch kit for my son's old toyota.

I couldn't get the thing to release. After umpteen iterations of the bits I worked out that it had the wrong bearing, it was thinner than the old one.

I was able cut a spacer to take up the slack out of the inner part of the old bearing after which it worked. (it was case hardened but the separating disks cut through it)

By the end of the whole exercise I could remove the clutch and refit it in world record time.

[graeme]

Hi Christian,

 

I have taken some photos of my TR4 Clutch arrangement. Hope they are of some help

 

 

Clutch fully at rest

 

 

Operating arm about to operate clutch.

 

 

Clutch cover which appears different to your cover!

 

 

Hope they help.

 

Cheers

 

Graeme

[RogerH]

Hi Graeme,

your signature tag 'if it ain't broke, fix it till it is' reminds me of the definition of an Independant Financial Adviser (IFA) -

 

'A person who invests your money till it's all gone'

 

 

Sorry a little off topic

 

Roger

[randall977]

Hi Graeme, really useful photos - thanks for posting them! Your cross shaft lever (the one which connects to the slave push rod) is further forwards (towards the engine) than my old one - this appears to be a much better setup than mine. I won a new (used) one off eBay which just arrived a few days ago and it looks much healthier than my old one. I hope to get everything refitted tomorrow - it has to work as I will have replaced every component. I may have mentioned this but I'm left with three potential faults;

 

1. The previous new clutch plate (from the TR Shop) was different from the one shown in the WSM and caused the problem - unlikely as the bits that count are correct.

 

2. The pressure plate was faulty - looks and feels perfect however the clutch would not disengage but bent the tapered pin - twice!

 

3. My cross shaft is damaged (possibly slightly twisted) - very likely as the original tapered pin had snapped and the cross shaft damaged during its removal.

 

Thank you everyone for your help - I hope to have a satisfactory conclusion to share soon...

[Ian Vincent]

Hi Graeme, really useful photos - thanks for posting them! Your cross shaft lever (the one which connects to the slave push rod) is further forwards (towards the engine) than my old one - this appears to be a much better setup than mine. I won a new (used) one off eBay which just arrived a few days ago and it looks much healthier than my old one. I hope to get everything refitted tomorrow - it has to work as I will have replaced every component. I may have mentioned this but I'm left with three potential faults;

 

1. The previous new clutch plate (from the TR Shop) was different from the one shown in the WSM and caused the problem - unlikely as the bits that count are correct.

 

2. The pressure plate was faulty - looks and feels perfect however the clutch would not disengage but bent the tapered pin - twice!

 

3. My cross shaft is damaged (possibly slightly twisted) - very likely as the original tapered pin had snapped and the cross shaft damaged during its removal.

 

Thank you everyone for your help - I hope to have a satisfactory conclusion to share soon...

 

 

If it has to be one of these three, my money would be on the pressure plate binding somewhere and as a result snapping or bending your tapered pin.

 

The cross shaft is a fairly meaty piece of steel and the torque necessary to permanently strain it would probably have resulted in failure of the clevis pin first.

 

Rgds Ian

[randall977]

I thought so too until I removed the pressure plate for the third time and tested it...for the third time - every thrust bearing claw goes down without any trouble when you push down with your foot...

[randall977]

The new cross shaft is not exactly the same as the old - the hole is about 1/4 inch out and there is no groove for the locking pin. I was told it was for a TR4 but I think it might be off another Triumph. I tried fitting it and it does actually fit so really I wouldn't mind knowing if the lack of locking pin groove is a problem - was this part ommitted on later TR's?

 

[RogerH]

Hi Christian,

the shaft without the waisted location groove is from a TR6.

This is a good thing (IMHO)as it allows the shaft/bearing to self centre on the gearbox nose/pressure plate and may make it easier to press down on the pedal.

 

Roger

[randall977]

Thanks Roger - I will go ahead and fit it then! I have found that the original cross shaft is slightly bent - probably by about 1/8 inch - makes it hard to get the operating fork on and certainly will have added to (maybe caused) my problems!

[randall977]

I managed to get the gearbox back in in literally two minutes (excluding bolting it all up etc). The new clutch feels smooth, just like a new clutch...which it is. IT STILL DOES NOT DISENGAGE - it has exactly the same movement as before!

 

The conclusion is that the master cyclinder I bought off eBay for £25 (3/4 inch bore) is not pushing enough fluid down the pipe. It has to be the problem. I had a replacement with my spares which was 0.7 bore, but ruined by damp...if I'm not mistaken 0.7 bore would make the problem worse...am I wrong? This is where I got my new master cylinder from (see link below), notice the '?' - significant? Any comments greatly appreciated! The gearbox is NOT coming out again!

 

EBay Clutch Master Cylinder

 

Would this one be any better?

 

eBay LHD Clutch Master Cylinder

Edited August 27, 2010 by randall977

[Alec Pringle]

Ebay is fine if you know just what you're about, and exactly what you're buying. Exactly as in part number, for example. It's not usual for aftermarket pattern items to be devoid of a part number - it's on the item, or the packaging, or both. The manufacturer publishes catalogues, appplication lists, cross references, etc etc.

 

The moment I see a new item without a part number detailed, alarm bells ring. As soon as I get to the caveats about 'may require slight modification', 'may require XYZ to be swapped', or 'please ensure suitability for your car' . . . . then I know the seller either doesn't know what he's on about, or doesn't really know what he's got, or is pulling a flanker. Whichever way, odds on he's talking bollocks. As I've learned the hard way, the net result is a waste of my time, effort and money . . . . and attempts to return a wrong 'un for refund are either unsuccessful or costly, or both.

 

A new clutch master from the likes of Moss or Revington or TRGB or TR Bitz or whichever TR specialist is going to be around fifty quid, and like as not it will be a proper item which simply does the job it's supposed to. If there's a problem, specialist TR suppliers are, in the main, pretty good at resolving the problem. Yes I know there are occasional exceptions to every rule - and we all make lots of noise on the occasion when something isn't as expected, whereas the other 49 times when the item is just what we want . . . . we simply get on with the job and say nowt.

 

There's a lot to be said for sticking with one or two specialist suppliers - they are all pretty good at looking after regular customers, and their advice can be worth a heck of a lot of time and frustration, not to mention money, saved. Just as this week a few minutes on the phone in a couple of calls to S&S saved me wandering down the wrong garden path re Tom's TR7 rear axle rebuild - thanks Simon and Rick.

 

So forget the anonymous ebay items, and deal with someone who knows what they're doing - and for a TR4 on the original type clutch I'd personally want a 3/4" bore master, maybe even a 7/8" if wear in the operating assembly demands it, even if the bigger bore does mean a heftier prod on the left pedal. And no, I wouldn't use a 0.7" bore item, let alone one that needs cobbling.

 

Cheers,

 

Alec

[randall977]

Good points, well made. So the one I have fitted is 3/4 inch bore (as it should be) - my spare which I couldn't use was 0.7 bore...which would have been worse. Even though I bought a cheepo part surely the bore dictates the volume deliverd to the slave which should be 2:1. I feel it's my only option to buy a new one but again there doesn't seem to be a clear fault, it's a guess really...and my last one!

 

After this I have no options.

[graeme]

Christian,

 

This is getting beyond a joke

 

I am grasping at straws to help you now. Have you changed the operating fork, if not, could this be damaged or an incorrect item?

 

I don't believe it is the cylinders because the cross shaft appears to not be in the right position at rest.

 

Is there anyway the crank can be too far forward?? Anybody else answer that one.

 

 

Best of luck, you need it.

 

graeme

[RogerH]

Hi Christian,

1. is you slave cylinder attached to the Front of the triangle shaped plate (with the stay to the sump).

2. is the triangle shaped plate attached to the REAR of the G/B front flange.

 

With all the new stuff the lost motion must be to do with the slave.!!!

 

Roger

[randall977]

Thanks very much for all of the advice. I should say that the slave is now correctly positioned and there is the correct amount of play, the position of the cross shaft operating arm is now perfect. I have now replaced every part of the clutch system from the slave and in the bell housing. The one anomalie is the cheapo (see above) master cylinder off eBay however it is 3/4 bore and appears the same as the original. I have just ordered a new one from Moss as it is my last option really...

 

If the crank were to far forwards (towards the front of the car) what difference would it make? If somehow it was then the operating arm would be in the wrong position as the thrust bearing would have further to travel until it engaged; however since replacing the cross shaft and fork it is now correct. The fly wheel would have to be at least 1/4 inch too far forwards for the clutch not to disengage. There is a hole in the base of the bell housing (made to access a seized clutch plate at some point in the past)through which I can feel the pressure plate lifting when I depress the clutch; it only lifts about 1/10 inch - which I can feel is not enough.

Edited August 28, 2010 by randall977

[TorontoTim]

Hmmm - it looks like you have gone through everything - at least twice!! Ok, how about testing everything in sequence against known answers from people who's clutch parts are identical...and WORKING! Here's the type of sequence of steps I would take...

 

1. check that the end of the clutch pedal (where it connects to the master cylinder piston) has a ROUND hole and not too oval

2. disconnect the slave cylinder from the operating shaft and, with the help of a willing assistant, measure how far the push rod moves when the pedal is depressed (take care it doesn't get pushed right out). Check this measurement against a similar measurement take by some helpful soul on the forum.

3. Try the same measurement when the push-rod is reconnected to the shaft.

 

Assuming all those are ok, you've got to assume it's NOT a problem with the hydraulic system.

 

Try the same, systematic, one component at a time tests with everything else.

 

Now it's true that it COULD just be a combination of small-increment "failures" with everything (e.g. not QUITE enough push-rod movement, too much end-float in the crankshaft, etc.) but, hopefully, you can find where the big problem is if you test each thing in sequence, moving step-by-step from pedal to fly-wheel.

 

I can only imagine your frustration......actually, on second thoughts I think I've been here with other problems over the years - usually electrical!! However, you have lots of support here on the forum. And, if all else fails, you can always take it to a professional!

 

Good luck!!

[randall977]

Thanks Tim, good stuff! The hole at the top of the pedle is a bit oval but I don't think this is the main problem - it's something much bigger. If anybody could tell me how far the slave cylinder push rod should travel when the clutch is oporated that would be a great help as I don't know if my 3/4 inch of travel is correct...

[Ashley James]

it only lifts about 1/10 inch - which I can feel is not enough.

 

If it's lifting 1/10" I'd say that's more than enough to be completely free and that something is actually wrong with the clutch assembly. Normally they free off the moment there's the tiniest clearance.

 

Ash

[randall977]

Ash, don't scare me! Maybe 1/10" was much too generous it may have been a lot less - I can detect it moving so maybe it was a fraction of an inch. The clutch is slipping when I put my foot down on the pedel so it's close to being free but it also slipped before I replaced all the parts...this is why I'm thinking the problem is the the master cylinder as it's the one bit I haven't replaced - twice.

 

Can anybody tell me how far the slave cylinder operating rod (or piston itself) should move when the clutch operated?

[Guest ntc]

Ash, don't scare me! Maybe 1/10" was much too generous it may have been a lot less - I can detect it moving so maybe it was a fraction of an inch. The clutch is slipping when I put my foot down on the pedel so it's close to being free but it also slipped before I replaced all the parts...this is why I'm thinking the problem is the the master cylinder as it's the one bit I haven't replaced - twice.

 

Can anybody tell me how far the slave cylinder operating rod (or piston itself) should move when the clutch operated?

 

 

Lucky for you Emoes was here and a car on the ramp the total travel at attached arm central hole is 17mm.

[randall977]

Thanks Neil, I just measured the travel on mine (centre of the pin through the middle hole) and I found it to be 14mm (though I measured it on my own so might be out by a mm or two!) - is 3mm really enough to make any difference?

Edited August 29, 2010 by randall977

[TIMS]

Christian

 

The illustrious (?) Mr Williams in his book on the 6 says that "The slave cylinder push rod needs to move at least 0.625ins (16mm) and to be connected to the middle hole.."

 

If you have 14mm then you only have 87.5% of the required movement. From my little experience this missing 12.5% is more than vitally important.

 

So if having checked the movement with a second person pushing the clutch you only have 14mm I would point you to outside the bell housing and back to the pedal and hydraulics.

 

You noted that the hole on the clutch pedal was "a bit oval", do not discount this. Is the clutch pedal hitting the floor? (You are trying all of this without carpets, underfelt etc etc?) If so does it feel like it could go further if there was no floor in place? (Or if the pedal hole was not oval). How much (technical word coming up) "slop" is there in the clutch pedal between the rest point where it is held up by the pedal return spring and when it starts to activate the master cylinder push rod? Anything more than very minimal is too much. Try removing the master cylinder to pedal clevis pin and operating the master cylinder with a big lever and get somebody to measure the slave pushrod travel with maximum movement of the master pushrod. See if you can get 16mm then.

 

I believe that Mr Revington produces an adjustable master cylinder push rod to help in this area. But if the clevis pin is tight on the master cylinder and pedal holes, and the pedal bearing bush is not sloppy this should not be needed.

 

Just thoughts in the early hours.

 

Good luck.

 

Tim

[Celtic2]

Have you checked the rubber hose to the slave cylinder? In one of my previous cars I had the problem of the hose deteriorating on the ID, although the OD looked fine. When pressurized it would swell slightly along the whole length without delivering the proper displacement to the slave cylinder. I honestly can't remember if it was a clutch or brake problem, but I do remember the many, many hours spent troubleshooting the problem.

 

gary

[randall977]

Thanks Tim and Gary. The hose (and everything else) is new so that one can be ruled out.

 

I checked the travel at the master cylinder and found it to be 30mm rather than 35mm (as the WSM recommends). Yes you are right Tim the last few mm's are vital - I hope this is where my problem lies - just need my new master cylinder to turn up!

 

In the meantime here is a photo of the car today - almost there!