Clutch despair

I have just over £1000 having my brakes and clutch sorted on My 1973 Triumph Stag at a Triumph specialist. It only went in for a service :(

The clutch had a new master and slave cylinder but it still has a major problem which I would be most grateful if someone could help me diagnose. The problem only seems to manifest itself when the car is fully warmed up, hence, I guess, why the garage thought it was fixed.

When the car is hot nothing seems to happen when I lift the clutch pedal to move away in 1st or reverse, then very suddenly the drive is taken up and we either move off really quickly, or stall.

It really feels like a sticking pedal as I can "Feel" some kind of resistance through the foot, and the pedal travel is not at all smooth, but really jerky and difficult to control. The funny thing is though, if I turn the engine off and then operate the pedal, it is pretty smooth, so I don't see how it can be a clutch pedal problem. If I turn the engine on but leave the car out of gear, the bad feeling in the pedal appears. As I have just had new master and slave cylinders, it can't be those (the problem was there before), and I don't understand how I could "feel" a difference in the clutch pedal if it was something further down the system, i.e the clutch itself or the gearbox.

Please can someone help me with something I can do to diagnose the fault. What could cause a jerky/sticky feeling through the clutch pedal that only comes when the car is hot, and only when the engine is running ? Right now I just feel like selling the car, and I simply can't afford to send it back in the garage having just spent so much, unless I can be sure of roughly how much more it will cost.

Reply to
loz
Loading thread data ...

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

formatting link

Reply to
Graham

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..

Reply to
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

Reply to
Andy Dingley

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)

Reply to
AWM

"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.

Reply to
DaveK

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

Reply to
Jon Tilson

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.

Reply to
Pete M

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

Reply to
awm

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

Reply to
sro

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.

Reply to
Willy Eckerslyke

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.

Reply to
Dave Plowman

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

Reply to
sro

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

Reply to
Andy Dingley

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

Reply to
awm

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.

Reply to
Dave Plowman

Just to add to this, IIRC its covered up to 3 years or 100,000 miles in the US. Would seem false economy to fit an under specced one.

Reply to
Dave Plowman

I have heard some BMW's suffered from tight splines on the input shaft. The disk hub would not slide freely when disengaging.

For 1000 quid I assumed the shop doing the work on the stag would have replaced the clutch disk, pressure plate and the throw out bearing as well as check and grease the input shaft splines.

Reply to
dsr

snip

Draging clutches if not down to the release hydraulics/cable are usually down to warped driven plates -- can happen when the gearbox and engine are mate up

Reply to
AWM

I'm not sure about this one, as lining dust will stick to the grease. I'd say there'd be enough oil mist inside the bell housing to prevent rust.

Reply to
Dave Plowman

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.