Herald clutch problem

[heraldhabitat]

I have done a lot of work on my herald, I have upgraded it to a 1300 engine a new clutch and recon gearbox, the problem is that the pedal is close to the floor when in operation, I had only left it a short while and the clutch had seized, the usual turn it over in gear cleared the problem. I have just left it for a couple of moths and the clutch is seized solid, no amount of starting in gear will clear it, I had it jacked up and run for half an hour in gear and still it hasn't released, any ideas? 37 years I've been heralding and never come across this one!

[Clive]

Duff cover??

[herald948]

I was thinking the same thing! OE-type Borg & Beck or ???? And "thinking" further about it, I don't ever seem to remember having this happen with an older-style coil spring clutch, but I've experienced it numerous times with diaphragm clutches.

[heraldhabitat]

Ah tis a diaphragm clutch, ah well the sump gaskets got a leak, i'll pull it out tomorrow. :o

[Casper]

Of course, the 1200 and the 1300 have different slaves.  I can't recall which way round, but the wrong combination does cause problems.
C.

[GrayFox]

Try putting it in gear with the handbrake on. Get a glamorous assistant to depress the clutch.  Remove the starter motor and with a tyre lever or suchlike tool try and tease the flywheel round.  You can spray in WD40 around the flywheel - this will need burning off afterwards.  And try using the car more often, mine is on the road every day and doesn't suffer this kind of problem.  Good luck

[Mark Hammond]

My 1200 (so diaphragm clutch equipped) seldom gets used (more's the pity) and never suffers this problem....

Mark

[heraldcoupe]

I spoke to Chris earlier, and recalled previous problems regarding Herald diaphragm clutches releasing only when the pedal is near the floor. Modern replacement clutches, even theoretically OEM supplied ones, have been modified in design compared to the originals. Result is the cover is shallower than the original, so the bearing face is closer to the flywheel, ie the operating range of the slave cylinder is right at the end of it's travel.
A proper engineering fix would be a taller bearing carrier, workable get-around is either extending the pushrod onto the release arm, or opening the pinchbolt groove in the slave so it can be slid further forward.

The seizing of the clutch may be unrelated, however it is possible though that with release point being a bit marginal, there isn't sufficient mechanical advantage to break any rust bond, after it's been sat a short while. With full travel, the initial binding of plate to flywheel might not even be noticed as sufficient force would be applied on initial actuation of the clutch,

Cheers,
Bill.

[MarkB]

In my experience that symptom has always been that the clutch plate has stuck to the cover plate and flywheel. This has happened to me on several occasions on Vitesses and spitfires, that have stood for a while even on a new 3 piece borg and Beck clutch stood in a dry garage I was amazed how much rust had built up between the surfaces.

[Nick Jones]

My experience suggests that the rusting is much more of a problem on vehicles with new/recently replaced clutches.  I suspect that after some use there is a combination of very fine oily deposits and nice shiny, polished (even lightly glazed) friction surfaces which inhibit rust formation.

I do agree with the theory that marginal clutch travel will make it harder to unstick a rusted clutch.  There needs to be enough motion to create an actual gap between the friction surfaces and break any rust seal.  If the clutch just barely clears, this probably won't happen.  Remember that the two friction rings in the friction plate are actually slightly sprung and will expand by 1 - 1.5 mm as pressure is released.

Nick

[Steve Cureton]

Nick_Jones wrote:

My experience suggests that the rusting is much more of a problem on vehicles with new/recently replaced clutches.  I suspect that after some use there is a combination of very fine oily deposits and nice shiny, polished (even lightly glazed) friction surfaces which inhibit rust formation.Nick

I think you're right there. I bought a non-Triumph ago where the clutch had been replced just before I bought it, but would stick if left without use for a few days. No amount of slipping to burn off any residue would work. I eventually removed the clutch and found fairly heavy surface rust on one section of the flywheel which had been causing the problem. In my case I was swapping the engine anyway and the replacement had a nice shiny flywheel, otherwise I would have had to have the old one skimmed.

[heraldhabitat]

I took the clutch out and I couldn't believe the amount of corrosion that has occurred it looks like the drive plate has reacted to the pressure plate and the flywheel, I had to use a screw driver and hammer to release the drive plate from the flywheel,, this can't be right in such a short time can it?

[herald948]

heraldhabitat wrote:

I had to use a screw driver and hammer to release the drive plate from the flywheel,, this can't be right in such a short time can it?

I wouldn't think so, but....

Guess you need to drive it more (often)?  ;D

[Pete Lewis]

if the heater(plenum) drain is discharging over the clutch housing it wont help, with rain water drizzling in .

the problems of sticking friction material and moisture content is a pay back for non asbestos materials

if the diaphragm is off have a close look there are pull off sprung tangs that withdraw the pressure platform as the diaphragm is operated, attached to keep the plate  up against the diaphagm.  if the cover gets dropped these can bend back under the weight of the dropping and there developes a gap between them and the plate , you press the diaphragm , it moves back away from the flywheel but it does not take the plate fully or equally with it and you get drag in extremes it wont release enough to clear the disc.

Pete

[heraldhabitat]

Cheers Pete it hasn't been out in the wet since the clutch was fitted, I have a new clutch complete and have adjusted the slave cylinder with a grinder, hopefully back in at the weekend, I am having the gearbox looked by Mick Papworth while it's out because all the forward gears and synchromesh are very good but it throws out of reverse, pointless putting it back faulty.

Thank goodness the clutch I put in the Courier last week was a stanpart new old stock one so I shouldn't get the same problem.

[herald948]

heraldhabitat wrote:

I am having the gearbox looked by Mick Papworth while it's out because all the forward gears and synchromesh are very good but it throws out of reverse, pointless putting it back faulty....

I'll be curious to hear the outcome of this. From a 2003 message to the triumph_herald e-mail list:

Re: [triumph_herald] gearbox popping out of reverse?

Oh yes, after some problems with this fault I eventually tracked the reason
down. Invariably it is to do with a bent reverse idler pivot, so the arm
itself doesn't run parallel with the gearbox case, I'm not quite sure why
this phenomena results, but it certainly does. It is possible to sort the
fault out without taking the box out, basically the gearbox rear extension
has to come off to gain access to the pivot, which can then be turned
through 90 degrees to make the bend irrelevant. If you want a step by step
of how to do it let me know - it would take someone who knows what they were
doing an hour or two to complete the job.
John Kipping

[Pete Lewis]

often jump outs are caused by the bolt thro' the bushes under the sperical is too long or wrong way round and it
actuall contacts the underside of the remote housing  

always worth a quick check before you £££££  

Pete