Clutch dragging question

[JJC]

When I rebuilt my 4 I put a later 4 synchro box in, a new clutch master cylinder, but used the original clutch. It looked good so took a chance. Unfortunately it juddered. Otherwise ok. New clutch in now. No judder but I can't get it to disengage completely. I have an adjustable push road and can get it to work when cold. When warm it drags slightly. Also no slack at slave cyl when clutch engaged. Any thoughts? JJC

[trerynn]

Try and eliminate all lost motion through worn pivots and pins in the clutch system, and did you cross pin the release bearing fork, the bolt may have broken or be loose causing lack of motion to release the drive plate.also the cross shaft bearings may be sloppy.

[JJC]

Thanks - but I don't think I'm suffering from any of those!

[AlanT]

You didnt tell us anything about where you got the new clutch.

Did you just swap the friction-plate on its own or fit a complete new unit.

 

I would guess that the new friction-plate may be a bit on the thick sidefor the rest of it.

You may be in luck and it will wear in.

 

Al.

[JJC]

It came from Moss. B & B made by AP so I would have thought it would be ok. It's odd that even with no slack when hot it doesn't quite disengage. Does when cold though. I've used the throw out bearing as for the early clutch. I wouldn't have thought the combination of late gearbox with early clutch and throw out bearing would be the problem but I'm not knowledgeable enough to really know. Just seems like not enough throw from the slave cylinder. JJC

[AlanT]

This may help.

 

http://www.buckeyetriumphs.org/technical/clutch/ReliableClutch/ReliableClutch.htm

 

Al.

[JJC]

Al - thanks. Wouldn't things like that be good in TRAction! I'll have to try and print it off to read it properly. He's right about gbox out being a 6 chiropractor job. JJC

[AlanT]

Since you like this kind of stuff:

 

http://www.vtr.org/maintain-index.shtml

 

The Buckeye stuff was written by a very eminent engineer called Nelson Reidel and originally appeared under his name. I rebuilt a gbox and OD virtually just following him.

 

Later it dissapeared and VTR wrote their own under Greasy-Hands. Also excellent. So now we have two superb sources to fix the harder mech stuff from.

 

Al.

 

Al

[JJC]

Al - that's brilliant. I like the GT6 at the top. Great little cars. Back to my clutch! Thought it might be air left in the hydraulics. Always had difficulty bleeding the thing. The pipe routing doesn't help. After a long search found my pressure one man bleeding kit. All I achieved was getting silicon fluid everywhere. JJC

[AlanT]

There is a current thread on the TR2/TR3 forum about fitting gbox from saloons. This is long but interesting and got me thinking.

 

It may be that the clutch you have, excellent though it looks is not exactly what was originally fitted. Maybe its a saloon clutch really. The thread goes on about using these. Perhaps the friction-plate does not match the diaphragm.

 

I happen to have a gearbox with the clutch on it, out of the car at the moment. So I could photo it maybe. The parts of this were not bought recently and are likely to reflect the original build.

 

If the lever moved more would this fix your problem? Or have you hit some kind of mechanical limit to movement somewhere.

 

Just thought, you have got the right diameter of master-cylinder?

 

Al.

[JJC]

Al - it looks as though a bit more movement would solve the problem. The master and slave cylinders are both Moss replacements so I would guess should match each other. I'm hoping it's air in the hydraulics despite repeated attempts to bleed it. Will borrow friends pressure bleeding kit next week and give it a go. I'm told that the pipe routing and bleed nipple position make it a pig to bleed. Have always had difficulty with the other TRs which have the same routing. Will let you know how I get on. Fingers crossed I don't have to get the ######## gearbox out again! JJC

[AlanT]

I get the original hydraulics refurbished or find some NOS. This is the kind of item that that repro parts often aren't really up to the job.

 

The clutch master has a bigger piston than the brake if I remember correctly.

 

Al.

[stuart]

The pipe run shouldnt make any difference and as long as the slave cylinder has the bleed nipple uppermost then bleeding should also be easy as well though as you are using sillycon fluid its more than likely that its full of air still.

Do you have the slave cylinder the correct side of the mounting plate and the clevis pin in the centre hole? Have you replaced the flexi pipe?

A saloon clutch will only fit a saloon gearbox as the input shaft has a different spline.

Stuart.

[JJC]

The pipe run shouldnt make any difference and as long as the slave cylinder has the bleed nipple uppermost then bleeding should also be easy as well though as you are using sillycon fluid its more than likely that its full of air still.

Do you have the slave cylinder the correct side of the mounting plate and the clevis pin in the centre hole? Have you replaced the flexi pipe?

A saloon clutch will only fit a saloon gearbox as the input shaft has a different spline.

Stuart.

 

Stuart - yes to all the questions! The thought on the pipe routing is that it goes up from the master cylinder over the battery and down. So it might be difficult to push all air bubbles over and out as it were. Hence the thought of using the pressurised bleeding system. Thankfully I do use siily-con, because about £10 worth of it went all over the bulkhead. No paint disaster because it's silicon. Whilst it's true that hydraulic systems shouldn't leak somehow or other fluid always winds up in the wrong place. Anyway, will report back next week if I have any luck with finally getting this car into routine use. JJC

[JJC]

Would be very grateful for a picture of a working (!!) push rod and arm. It's looking like the pin holding the clutch fork to the cross shaft is the problem. This would allow the arm to be rotated relative to the cross shaft and cause the problem. Thought I'd replaced it but not sure now. I need to see the correct position of the arm and compare it with mine. Are the TR2 and 6 the same? I could look at those if they are. JJC

[stuart]

Try this, ignore the pushrod as some DPO has butchered it but the angle of the arm into the box is correct.

Stuart.

[JJC]

Stuart - many thanks, very helpful. Another beer I owe you. JJC

[littlejim]

To get my new Moss clutch to disengage I had to put the rod into the top hole in the lever and wind the adjuster nut on the rod almost to the end of the rod.

Put it up on blocks with the hand brake on and "tuned" it with the rod adjustment.

Wondered whether Moss gave me a bit of extra lining above what I paid for.

haven't done many miles on the clutch plate yet, maybe a couple of hundred miles, but haven't needed to move the rod down to the bottom hole or wind the rod in yet.

[JJC]

Just in case anyone's interested - the story so far. The pressure bleeding kit worked when assisted by a huge adjustable spanner to stop the cap leaking. The clutch has improved but when really hot still drags very slightly. Does not drag at all when cold. I have wound the push rod out a touch more and will road test when the rain stops enough to see the road. The problem is that there should be 10 thou clearance between push rod and the clutch lever. I haven't got any at all. Can't be right can it? All seems to be suggesting not enough throw on the push rod. JJC

[JJC]

Looks like it's fixed. Thanks to Stuart for helpful advice and for the comment from littlejim. There wasn't enough movement from the slave cylinder push rod, only by about 1/16th but enough to cause trouble when hot. So I used the top hole on the lever. Hopefully that's it. JJC