Clutch not disengaging?

[Baxter]

I just tried to drive the car - the first time it would have moved under its own power since 1979.  I can't put it in any gear as the 'box seems to be still spinning fast after fully depressing the clutch.  I can see the push rod in the slave cylinder operate on the correct position on the release arm, and both move.  Maybe not as much travel as I would have expected.  Any ideas?  I put a new clutch in before installing engine first time 18mos. ago and thought I was pretty careful about assembly.  Would be great if there was some simple test/fix...I'd love not to have to take the gearbox out now after just installing engine and 'box for the third time!

Baxter

 

[glang]

It sounds very much like your clutch friction plate is stuck to the flywheel. First you need to be sure the pedal is working correctly and it's not a hydraulic problem. Once your 100% you can try to break it free by carefully starting the car in gear but up on rear axle stands. Then on high tick over press the brake and clutch pedals together to try to unstick the plate. It's a bit brutal but the alternative is gearbox out....

[Clive]

You have said the mechanism seems to be working correctly, so I would agree the most likely problem is clutch plate "stuck" to the flywheel.

I would run the engine up to temperature to get a bit of heat into the clutch. I have done various things to free clutches, all successgful.

1. With car in gear, footbrake firmly pressed and clutch pedal down, try to start the car. 

2. Raise the rear wheels securely, start the car in gear (2nd) and with the clutch pedal down, keep flicking the accelerator. Quite gentle really. Car does need to be well secured though!

No reason the above method posted by glang shouldn't work. 

It is odd. Some clutches will stick after a very short time. Others seem never to stick, even after a few years. No rhyme or reason.

[Baxter]

Glang and Clifty, thanks so much for your swift and encouraging responses.  I may even head over to my workshop now to try this out.  Just how secure does the car need to be?  I can put the rear up on a pair of good quality axle stands, and stand something solid just below the diff

If need be, I can squeeze myself back into the footwell of despair and measure the distance the slave cylinder pushrod travels, in case anyone knows how much this should be.  Hydraulics still seem to be good, certainly up to level, since fitted and bled 18 mos. ago; though I do shudder seeing the slave cylinder being knocked like a game of Swingball each time the engine goes in or out of the car.

 

[glang]

As Clive says there doesnt seem to be any ryhme or reason to it and mine went through a phase of sticking easily and now never does it. Of course using it is the best protection....

The only possible hydraulic fault I can see which would give these symptoms and no major leak would be a leaking master cylinder shut off seal. This would allow the fluid to go back into the reservoir rather than operating the slave cylinder and can even give a feeling of correct operation at the pedal. If you mark the reservoir and then press the pedal the level definitely shouldnt go up!

[Baxter]

Tried Clive's methods 1 and 2 so far.  No joy after about 8 attempts the first way.

Onto method 2 and likewise nothing happening after many 'light flicks' so I tried a slightly heavier flick and it stalled.  Went to have another go, but the electric fuel pump has become unusually vocal on turning on the ignition.  Fuel gauge doesn't seem to work, and not really sure how much is in the tank after a number of idling and tuning sessions, so will rectify that before having another go at the clutch.

As for using it - can't wait!  My 12 month project is approaching 5 years now...and once the clutch is sorted, if there are no gearbox or diff problems, I'll probably be back asking for ride height advise, as it's sitting with the chassis about 3-4" off the ground and has no chance of negotiating the route to the road like that.  Also, I should add that the tunnel is still off, so I can see the slave cylinder operating.

[thescrapman]

Is it big saloon box or GT6?

[Baxter]

Pretty sure its the original box for this GT6.  I don't know how to tell them apart, but the entire project I purchased appears to be GT6 and it was just the 2500 saloon engine along with HS6s and manifold that I introduced.  No gearbox

[glang]

Pretty easy to tell the bigger box as the bell housing and case are integral and aluminium as opposed to the ally and cast iron respectively of the standard unit.

I believe unfortunately it's not so easy to squeeze in the larger one so you'll have drive your GT6 pretty easy if you want the box (and diff) to last well👍

[thescrapman]

Also slave is on the passenger side on a saloon box and top driver side corner on  GT6 box

reason I asked is that saloon boxes break the crosshaft pin, which makes disengagement difficult but still feels like it is working 

[Velocita Rosso]

Can`t remember without getting our GT out the garage....doe the slave adjust back and forth like the Spitfire....which does adjust back and forth.You may be able to see slave pin moving , but does it move far enough forward......or is the retaining pin in the bell hsg affixed .....or is the yoke attached?..All of which should have been checked before re-installation

[Baxter]

So, reading the above, it's certainly a GT6 box rather than a saloon one.

Slave is top right of bellhousing. No adjustment back and forth (other than possibility to add non-standard washers/spacers and use longer fasteners). 

Took all the care I could to ensure correct assembly and yoke in right place before sealing. But I've not done it before and mistakes can be made.  Not convinced there is enough travel to disengage clutch.  Will post link to video of operation here:

https://1drv.ms/v/s!AmjW3mQn-IqAjKlcSCCbXRLUtMpzpQ

Meanwhile had another good session using the 3 release methods detailed in above posts. No joy. Hard to describe what happens...maybe a jolt and a slipping/rubbing sound trying glang's approach. Clive's #1 plenty of force evident but nothing else. #2, just faster spinning of back wheels with each flick.  I guess a video might be useful next time.

Thanks for all the help

[RobPearce]

I would say, instinctively (though without having checked either the GT6 or the Vitesse recently), that the piston is too far extended at rest. Since it doesn't look like you omitted the mushroom pivot, are you sure the fork is correctly engaged in the correct release bearing?

[Baxter]

Here are the parts I used, though I replaced the release bearing with the new one from the clutch kit before fitting.

There only seemed to be one way to fit everything together, with the recess/clip (on the back of the release arm in my photo) clipping over the fulcrum pin inside the bellhousing, and the pins on the end of the release arm fitting into the groove at the RH end of the bearing carrier.  This left everything lined up with the slave cylinder (which I sourced new, but matching the heavily corroded one found among the project parts).

Depressing the clutch pedal, I've always been concerned that there is not enough movement.  Unless there are any more ideas, I will proceed with gearbox removal.  Not such a problem, as everything so far has needed overhauling or replacing, so I've been expecting to need to work on the gearbox anyway.  Would just have liked to try driving it first to assess function.  I've never worked on a gearbox, so can anyone recommend how to get it assessed before I put it back in.  I'm based in Cirencester but generally happy to drive a fair distance to get things sorted.

[glang]

That all sounds correct although I agree with Rob that compared with the WSM the operating rod does look a long way out. According to the manual (available free online if you havent got it) the max travel of the thrust bearing is a shade over 7mm which I calculate should be about 12mm at the rod....

With the box its not easy to do an assessment without stripping it as the most problematic bits are hidden. However obviously it should turn smoothly, have limted play on the input shaft and select gears nicely. Then by taking the top cover off you can check for debris and the condition of gears and synchro rings. This wont guarantee a good box of course but if all ok gives some hope that it hasnt done excessive miles and will give more service.

[Steve P]

So it`s a 2.5 engine with a GT6 box,so which engine backplate,flywheel and clutch was fitted?.

I have a 2.5 Vitesse but i used a saloon gearbox, Vitesse  backplate and flywheel.

Clutch geometry took ages to get right and included chopping the slave operating rod to different lengths to get right.

Yours looks like it`s too far forward and not disengaging.

Steve

[Velocita Rosso]

Quoted from Steve P-

So it`s a 2.5 engine with a GT6 box,so which engine backplate,flywheel and clutch was fitted?.

I have a 2.5 Vitesse but i used a saloon gearbox, Vitesse  backplate and flywheel.

Clutch geometry took ages to get right and included chopping the slave operating rod to different lengths to get right.

Yours looks like it`s too far forward and not disengaging.

Steve

I agree...its the operating rod not being effective enough

[Clive]

A few weeks ago I was helping a local with their vitesse clutch. It was a bit noisy, but I was able to see the clutch release bearing while everything was fitted up and the car running. Turned out to be the release bearing causing teh noise, but only when just in contact with the cover. Any pressure on the pedal and the noise disappeared, move the bearing away from the cover with a long screwdriver, again quiet. New correct RHP bearing fitted....

 

I am wondering if the correct slave cylinder is fitted? several identical ones out there but with different (larger) bores meaning not enough movement. One of those available at low price is a landrover item. Sold as suitable probably by somebody, because it looks the same.

[glang]

As I say it looks to have about the correct 12mm of travel so Im guessing the hydraulic side is good....

[Steve P]

There are also different length carriers,the brass one is the same as i had on the Vitesse,i had to change to a steel saloon one when i replaced the clutch with a paddle type plate as it was not disengaging and giving big clutch slip when booted.

Saloon flywheel is thicker than the GT6/Vitesse one hence the shorter carrier.And they weigh as much as a small moon.

Also i experimented with Vitesse 1600 and saloon slaves to get different travel.

Need to know what components you have otherwise it`s all guesswork.

S

[thescrapman]

Good thought on the flywheel.

Did you use the GT6 or saloon flywheel?

 

[Baxter]

Evening chaps, I'm almost overwhelmed by the level of help you're offering, and sorry to have been out all day taking my son and his friends to the football.  It seems there are questions to be answered!

I may not be able to answer correctly, so first let me tell you how all these parts came to be in my workshop.

The GT6 had apparently sat first in a garage and then out under a tarp from 1979 to 2011 when the PO bought it and restored almost the entire chassis and body.  The rest (including rusted-up clutch, release arm, bearing/carrier) arrived in many boxes, and as the car had laid untouched for so long, I think most items are original.  The original engine arrived whole, and I plan to completely rebuild it, slowly and carefully.

To speed the project up and have a bit of fun - or so I thought! - I bought the 2500 MM engine as an interim: it came out of a GT6 mk3, had since been rebuilt, and came with flywheel attached.  I've since found out (and documented in a previous forum post) that it had a saloon sump and was a bit too much of a squeeze between bonnet and steering rack for my car.  So, can I trust that the flywheel really is from a GT6.  Probably not.  I guess there's going to be a quick way to determine this.

The seller also provided a new Borg and Beck 3 part clutch set that he said was correct for the engine/GT6.  He was a very experienced and trustworthy member of this forum, whereas I knew very little, so his answer will stand here.

The slave cylinder I would have purchased by looking up the part for a GT6 mk1 at Canleys, James Paddock or maybe Rimmers.  Should I be buying parts for a GT6 mk1, I always ask myself, if they're being fitted in relation to non-GT6 mk1 items?

So my tentative answers are:

Engine backplate, flywheel, clutch - all GT6 mk3

Slave cylinder - GT6 mk1

Carrier - GT6 mk1 (this is the only answer I have faith in!)

Given what Steve P says about carrier length matching flywheel, I'd best establish which flywheel I have.  Maybe it's then worth me taking a look at the whole setup in operation like Clive did...find out if I can also see the bearing, and if a long screwdriver could help.

 

[glang]

Looks as if were homing in on the problem and its like a murder mystery🤣 Just a suggestion before you strip everything but could you pack out the mounting of the slave cylinder temporarily to see if the clutch disengages?

[Clive]

If you can get to see inside the bellhousing, you should be able to identify the flywheel, especially if you have another to compare. The 2.5 one is MUCH thicker

Thinking about this, and probably getting confused, I think...

The saloon and GT6 clutches are the same. As are the release bearing.

The saloon flywheel is thicker, so is the release bearing carrier shorter? 

Is the clutch plate the correct way round? 

If the clutch slave was sold by one of the supplier mentioned I would expect it to be correct. 

 

The upshot...I think teh box needs to be pulled out. If the  tunnel etc is not fitted then it shouldn't be too tricky. Be thankful it has an alloy bellhousing!

[Baxter]

Okay, based on your advice, I'll briefly investigate further while it's all still assembled.  Probably don't need to spend too much time peeking inside the housing, as I have a photo (below) showing flywheel and clutch during assembly.  Is the friction plate the right way round?

Moreover, with the engine started in 2nd gear, I'll see if I can operate the release mechanism with large screwdriver or packing of the slave cylinder.  Might give useful clues for what needs to be done.  

Then I'll crack on and take the box out.  Goodness knows it'll make a nice change from taking the engine out, and it's already a few degrees less cold in my shed than during the last operation.  Will try to get on with this today while I have so many helping and hopefully enjoying the murder mystery.