Clutch despair

Could the rotation of the clutch assembly be twisting the clutch release bearing/release arm out of alignment and stopping it moving back and forth freely? I assume the bearing is supposed to slide on some sort of sleeve attatched to the gearbox.

Regards, Graham L

It sounds like the clutch release bearing is sticking on the gearbox input shaft. Puzzling why this would only happen when the engine runs though. It can't have been the master or slave cylinder because these wouldn't be affected by whether the engine was running or not as far as I can see. You might want to ask them to consider that diagnosis and refund that part of your money. Also if all the clutch components were changed then clearly that part of it hasn't fixed the problem either. They should fix FOC or refund.

Finally, I'm also wondering if the crankshaft spigot bearing is worn out causing the gearbox input shaft to wobble when the engine is running. Not a common fault but easily checked when the clutch is being done. Also easy to overlook of course as you wouldn't generally check that.

There are a limited number of components in the clutch mechanism so anyone competent ought to be able to run through them and identify the problem area. Sounds like you've had parts changed at your own expense based on guesswork rather than logic. The small claims court is your friend if polite negotiation fails.

Dave Baker - Puma Race Engines

I'm not at all sure why women like men. We're argumentative, childish, unsociable and extremely unappealing naked. I'm quite grateful they do though.

Was this the problem originally? Has the car always suffered this problem ? If so, it sounds to me like either the clutch plate / pressure plate itself is faulty, and binding, or the gearbox input shaft is bent (from changing the clutch and hanging the gearbox on the input shaft without any bolts in the bell-housing) but why it should bind only when hot I am not sure.

Tim..

Got any oil leaks ? Could be oil on the plate

But I hate to tell you, sounds like some monkey has either bent your gearbox input shaft, or the gearbox front bearing is on its way out.

If your garage charges a grand for swapping two masters, then I dread to think what looking at the clutch costs.

-- Smert' spamionam

Dosen't fit any definite known set of symptoms, only thing I can think of is a cracked clutch diaphram, or the spigot bush is missing from the flywheel, but it could still be hydraulic. On the hydraulic side I would check the master cylinder pushrod has clearance (ie it allows the piston to return fully) and the the mastercylnder resevoir cap vent is clear (try just leaving the cap off for a short test run). I were charge 1000 pounds for just a complete brake overhaul and new brake and clutch hydraulics on a Stag I would be furious, anyway you look at it they must have charged you 400 pounds for labour. As an experienced workshop manager I would expect a good mechanic to do the lot in less than 5 hours (30 minutes per front wheel for discs pads and calipers, 2 hours on the rear brakes and cables , 45 minutes to fit new brake pipes, 45 minutes on clutch hydraulics, 30 minutes to bleed brake and clutch)

Pilot bushing is the first thing that came to mind for me as well. They are only a few pence and a good shop would have considered this if the car does not have a floating clutch.

"loz" wrote in message news: snipped-for-privacy@posting.google.com...

The cost of new master and slave cylinder would be about £100, easy job- shouldn't be more than £50 to fit. Don't know what they did with your brakes but no more than £300 to supply and fit lots of parts. The clutch could be one or more faults. Maybe the clutch diaphragm spring is knackered. The symptoms would be a sudden release of the clutch, no gentle taking up of the drive (like a clicky frog spring). It's also possible that a very worn clutch release bearing and/or friction linings could cause the problem. As suggested, oil on the linings could cause it to drag then suddenly release. Maybe there's damage to the gearbox input shaft splines and/or the mating splines on the clutch driven plate. That could cause the driven plate to jam on the shaft. When it all gets hot, things expand and maybe makes it worse. The phospor bronze pilot bearing in the end of the crankshaft might be chewed up and seizing the gearbox shaft (so rare it's unlikely). There's so many possibilities but they all lead to one thing - replacement clutch assembly. While it's apart, check the gearbox shaft for damaged splines, remove the rear crankshaft bearing block and stick in some new oil seals and a new pilot bearing in the end of the crankshaft. The cheapest possibility is that your monkeys didn't bleed it properly and there's air in the system. As you can select first gear from standstill this is unlikely. I'd be putting it into one of those specialist clutch centres. DaveK.

Is it possible that the replacement of the slave cylinder required separation of the bellhousing from the engine? I'm thinking that the alignment dowels may have fallen out/gotten pushed through the bellhousing/something and that the input shaft of the tranny is no longer aligned with the crankshaft. This can also happen if the engine and/or tranny has been replaced at some point in time. If the latter is the case, you should really have the bellhousing dialed in before you start tearing your hair out.

Granted, this is all based on my experience with American cars. I have swapped transaxles in VWs before and have never once dialed one in, and never had a problem. It's all in how precise the machining is. Maybe someone with some Triumph experience can chime in here and tell you whether I'm leading you down the wrong path or not.

nate

good luck

nate

I'm intrigued....If you are anywhere near west london I will look at it for nothing.... If I can fix it the quote will be reasonable...time and materials only. I reckon you have a duff master cylinder with the piston sticking in the bore. I had this on a Dolomite once. Stag clutch hydraulics are a doddle... Not so sure about dropping the box though. I doubt I'd be economic at that. Specialist clutch fit place would be best and look at gearbox input shaft and spigot bearing when its all out. Make sure main shaft rotates freely relative to input shaft when box in neutral too....

Jonners

Jonners

Jon Tilson waffled on in a quite bewildering manner to produce...

Dunno, but my brother had an 02 plate BMW 520i that's similar, the clutch is awful, always has been. I suspect it's either the clutch sticking on the input shaft or a warped clutch plate. Seems to bite twice, initial one is soft and near the carpet, then it bites like a p**sed off tiger again at the top of the travel. Didn't get any better over 63000 miles, went into BMW seven times, problem was recognised, until BMW described it as a "characteristic" and refused to do anything else to it. He no longer drives a BMW.

That one would be easy to diagnose either warped driven plate or cracked diaphram

Bent an input shaft - you are kidding arent you ? Can that happen - has anyone done this ? I'm amazed if this can happen.....

Dave Baker seems to offer the best advice - unfortunately it will almost certainly require the gearbox to come out.

Steve

I'm glad you asked that. I was wondering about it too, though it is something we're often warned about. I'd have thought the bearings would give out before the shaft itself suffered any damage.

Yes. Every book you read warns against it but I've never seen it.

Triumph seem to have a problem with the design of their clutch withdrawal mechanisms. The Toledo ones could fall apart. And FWD 1300s always seemed to suffer from clutch judder.

Rover P6 seemed to often suffer from dragging clutches - even with all new parts.

You'd have thought after all these years a common foolproof design would have emerged. Perhaps the internal concentric slave cylinder that BMW etc use is the best way. But I doubt it.

Remember this problem only occurs when the engine is both hot and running. Also it's still there despite a new master cylinder. The only things that I can see being affected by the engine running must all be inside the bellhousing. It would seem that heat and rotation are causing something to jam. Possibly a combination of thermal expansion in a part and centrifugal forces or oscillations. I see no way the problem can be related to anything outside the immediate confines of the gearbox input shaft and crank.

So the box has to come out and all relevant parts checked for clearance and wear to OE specs. Not a complicated task but not helped by the money already wasted on parts that did nothing.

I suggest an immediate letter to the garage explaining that the replacement master and slave cylinder have not had any effect and therefore the original parts cannot have been at fault thus a refund for parts and labour on those items is requested without delay.

If it were my car I would remove the box, check the input shaft splines for wear and burrs, check the front box bearing for play, check the release bearing and any actuation levers for free movement, measure the crank spigot bearing and check the pressure and driven plate for cracks, broken springs etc. Also it would be sensible to make sure the flywheel is in good order and doesn't need resurfacing.

As a matter of principle it's best to replace all clutch components (release bearing, pressure and friction plate) while the box is out because it's a false economy to go through it all again when the one bit you thought had some life left in it packs up 5 minutes after the car is back on the road.

Dave Baker - Puma Race Engines

I'm not at all sure why women like men. We're argumentative, childish, unsociable and extremely unappealing naked. I'm quite grateful they do though.

Dont ford do a similar "build the slave into the g/box" job on the mondeo, so that, when the hydraulic seals fail they piss all over the clutch, which on older mondeos was an all day engine out job. I've never had a problem with the old style external slave clutch system.

Most clutch problems I've had are down to manufacturers specifying tiny clutches which arent up to the job - my E46 is a classic example, heavy handed use shags it in about 10k miles - the last owner proved this - beautifully overheated. I also suspect that friction materials arent always good - didnt Huw mention landrovers going through a phase of new clutches that just wouldnt grip.

Steve

Generally it's a per-vehicle question. Some boxes are hard to separate without hanging the box weight on the shaft as you slide them apart, some are easy. Some have weak shafts, some don't. If you get the first two, and a babboon mechanic, then you can have problems.

-- Smert' spamionam

Really only evey applied on cars with a really long input shaft -- such as the Moss box on some old Morgan models.

IIRC, they're not known for getting through clutches quickly - it's all down to the driver. I knew one bloke who knackered the clutch on an E-Type in under 2000 miles - flywheel and all. And he was a very slow driver.