Stuck Clutch: How hard can I push without damage?

[geodon]

Well, I bought my projet 2A with a clutch pedal stuck in the up posn & I was hoping to drive it a bit to assess the mech cond. before pulling it down.

I found the slave cylinder was siezed so I had a "Eureka" moment but on replacing it (plus both masters) & pressure bleeding ( I got a new plastic reservoir cap, drilled it & pulled a tubeless tyre valve thru it then hooked it up to the spare wheel. Yeah, it leaked but it lasted long enough to do the job!)

Sadly, the pedal is still stuck!

If I jiggle it I can see the clutch lever move but only up & down vertically as it takes up the wear. There is not a skerrick of twisting movement.

Any ideas before I get VERY heavy with it?

I can't see the point of pulling the GB out, fixing it, then it putting it back for testing then doing it again for the "re-furbishment".

I've already wasted about a litre of hydraulic fluid!

[isuzurover]

If you cannot depress the clutch then there is something wrong.

Normally a stuck clutch means you can depress the clutch, but the clutch has rusted to the flywheel/pressure plate so does not disengage.

The throwout "sleeve" may be seized???

If you remove the gear lever there is a small plate where you can look inside the bellhousing and maybe see what is happening.

You could also put it in 2nd low and start it - and drive around a bit and see if that sorts things out.

Is the gearbox full of oil?

[UncleHo]

G'day Geodon :)

That sounds like the pedal is seized on the pivot shaft up in the pedal box, where the mastercylinder push rod activates the master cyl,take the top off the pedal box (6 screws) and see if there is any movement, you could also unbolt the master and just pull it out of the way a little, that should give enough room to check the pedal, there should be a grease nipple in between the 2 pedal housings to lubricate the shaft on each one,if it is not that, just check if you have 0.003-5 thou clearance between the pushrod and the mastercyl piston, if not, then the piston may not be coming back far enough to allow the oil back through the return hole :)

If it a frozen clutch, (plate frozen to flywheel or P/plate) the pedal will operate normally but the plate is stuck to the pressure plate, engage first gear,depress clutch with handbrake on and hit the starter, if not then it will need a tow to free it, (common with vehicles that have been parked up for several years)

Hope that is of some help

P.S. what is your location Qld????

cheers

[isuzurover]

G'day Geodon :)

That sounds like the pedal is seized on the pivot shaft up in the pedal box, where the mastercylinder push rod activates the master cyl,take the top off the pedal box (6 screws) and see if there is any movement, you could also unbolt the master and just pull it out of the way a little, that should give enough room to check the pedal, there should be a grease nipple in between the 2 pedal housings to lubricate the shaft on each one,if it is not that, just check if you have 0.003-5 thou clearance between the pushrod and the mastercyl piston, if not, then the piston may not be coming back far enough to allow the oil back through the return hole :)

If it a frozen clutch, (plate frozen to flywheel or P/plate) the pedal will operate normally but the plate is stuck to the pressure plate, engage first gear,depress clutch with handbrake on and hit the starter, if not then it will need a tow to free it, (common with vehicles that have been parked up for several years)

Hope that is of some help

P.S. what is your location Qld????

cheers

It says he has replaced the MC - I would have thought a seized pedal box would have been diagnosed already???

[JDNSW]

Inability to move the pedal has to be one of the following:-

1. Seized pedal - remove cover plate on top of pedal box - slacken nuts on push rod - pedal should move freely, if not, free it (WD 40 + time should work , otherwise remove the whole assembly and disassemble)

2. Master cylinder stuck - slacken output union - if it still won't move but pedal was shown to be free, must be the cylinder.

3. Blocked line - open bleeder on slave cylinder; if it pushes fluid out when you press pedal, line is OK.

4. Slave cylinder or bell crank seized - remove the pin coupling the bell crank shaft to the clutch release shaft - if the pedal now moves ands turns the bell crank, the problem has to be either the shaft is seized in the front gearbox extension or the release sleeve is seized. Removing the cover mentioned by Isuzurover should enable you to get some WD-40 onto it and this may free it - but it is probably a gearbox out scenario, and does not bode well for the other gearbox internals - the gearbox has probably had water in it. Overfilling the gearbox with diesel or other very thin oil and leaving it for a few days may free it, but the condition of the gearbox would have to be suspect.

John

[geodon]

Yes I replaced BOTH MCs with stainless sleeved ones.

Pedals swung freely.

Slave WAS siezed hence I thought that was the problem. Not the case.

JD your thoughts on the GB are helpful. Thnx!

So I've got a dilemma!

I want to test drive it before I strip it to assess the mech cond. The 186 starts & runs fine. I can warm it up & do a compression test.

I can't test the GB & transfer case but if water in the box is the probable cause of the problem then it will need to be stripped & checked. I also can't check the diffs but, hey, they are easy enough to remove if necessary.

I have a spare GB. Is an overhaul do-able at home? Spec tools? Best ref book or website? Do any clubs have workshop days or "tool libraries"?

OK! Here's the plan:
Dismantle.
Wire brush the chassis and diffs
Cut & shut the small amount of rust in 1 outrigger & the bulkhead
Paint & re-assemble

I won't attend to the wheel bearings, hubs etc until the car is mobile again & I can see what's going on.

Did someone ask where I am? Bellarine pen near Geelong

[chazza]

They are fairly straightforward gearboxes to strip and assemble needing no special tools but I found it a lengthy business as I waited for spare parts to arrive. For me measuring things such as end-float on shafts and then ordering the right (fairly expensive) shims was the time consuming part.

Well worth doing properly and spending some money on quality parts,

Cheers Charlie

[UncleHo]

G'day Geodon :)

It could also be a totally blocked flexible hose, ti will give similar symptoms, the replacement hose part no is RTC3353 ;)


cheers

[JDNSW]

Use the factory workshop manual for the gearbox. I have not done one - never had to, but should be possible at home without too much trouble. The manual lists the tools needed for each operation. As chazza mentions, having to wait and order shims will waste a lot of time - a few spare boxes probably helps. Note that there are a number of revisions of the box (shown by the suffix on the box number) and some of the internals differ, so you need to be sure to specify the box number when ordering. Don't rely on the vehicle date or chassis number as the gearbox/transfer case is interchangeable from 1958 - 1971, and the transfer case by itself from 1953-1984, so there is no guarantee that what you have is original.

John

[geodon]

OK! I made a last ditch effort to solve this by taking off the floors & the GB cover before I gave up & started stripping it.

I removed the gearstick & the inspection plate on the bell housing & took photos.

It looks like the leading edge of top hat section that pushes on the pressure plate (ie the hat brim) has gone deep INTO the pressure plate because it has collapsed. The return spring on the pedal pulled the pedal back & so refilled the hydraulics but the top hat thingy stayed put. Hence when you press on the pedal, there aint nowhere for the thing to go!

25072



Comments??

[geodon]

Hang on!

That HAS to be a Holden spring diaphragm clutch so the thrust bearing is pushing directly on whatever number of springy fingers. I know from VW experience those fingers are prone to breakage so it's possible for the LR thrust bearing (because of its design) TO PUSH RIGHT THRU & remain there when a few fingers crack & weaken.

Is this a weakness peculiar to Holden conversions?

Are LR pressure plates diaphragm or coil springs?

[JDNSW]

Pressure plate has a serious problem. Possibly, it has had a Series 3 pressure plate installed - these do not work with a Series 1/2/2a.

The 2a originally had a 9" three finger plate (231888), but can be fitted with a 9.5" diaphragm clutch (GCC112).

The correct diaphragm plate for the 2a has a spacer attached to the release fingers to make up the extra space, distinguishing it from the Series 3 pressure plate (576557).

John

[geodon]

Is the LR flywheel bolted on or is the Holden flywheel typically retained?

[geodon]

This is what I saw when the GB was removed:
25624

And at the other end:

25625

So! We have obviously a Holden flywheel with 3- fingered coil spring pressure plate.

I reckon the wrong PP was used here. The 3 pressure points (no bearing surface, no lubrication) have rapidly worn down the LR thrust bearing until it was so thin, it just bent backwards towards the GB & became entangled in the fingers & wouldn't go back. The hydraulics back filled & just left the thrust bearing in a fixed forward position resulting in a pedal that would not depress. The ensuing prang has shaken loose 2 of the anti rattle springs in the friction plate too.

THe correct clutch should have a rotatable surface to meet the thrust bearing. Any ideas which one?

[geodon]

Sorry! Here is the 1st image

25626

[JDNSW]

No. The problem is that the clutch release bearing, which is inside the housing on the front of the gearbox, has seized, so that instead of the clutch release sleeve rotating with the fingers, it has remained stationary, resulting in rapid wear of the sleeve.

The clutch release bearing is lubricated by the gearbox oil, and failure of this bearing casts considerable doubt on the state of the other internals of the gearbox - failure is almost certainly due to either lack of oil or presence of water, although I suppose it is just possible that it is the result of either a driving habit or a clutch linkage problem that has resulted in the bearing being in contiuous use - but even this should not result in failure - all the other bearings in the gearbox are turning all the time.

The clutch release housing can be easily removed. At a minimum you will need a replacement release sleeve and bearing, and presumably seal as well, plus a new pressure plate and presumably driven plate. But I would at least take the top of the box and have a look at the works.

John

[geodon]

(I'd better watch the terminology as I have always called what pushes on the clutch to release it the "thrust bearing".)

OK I can understand that happening BUT my damaged clutch release(withdrawal) sleeve spins quite freely.

Notwithstanding that, is it possible for the the clutch withdrawal sleeve thrust bearing to sieze momentarily, do the damage & then free up again once it cools off or gets lubrication?

I'm having trouble getting my head around the fact that the thrust force to release the clutch can be applied by a disc to 3 points about 6mm square each. It just seems unnatural without another disc on the pressure plate to distribute the load. I suppose the key to it is that the disc & the fingers are spinning at the same speed, yes?

[JDNSW]

(I'd better watch the terminology as I have always called what pushes on the clutch to release it the "thrust bearing".)

OK I can understand that happening BUT my damaged clutch release(withdrawal) sleeve spins quite freely.

Notwithstanding that, is it possible for the the clutch withdrawal sleeve thrust bearing to sieze momentarily, do the damage & then free up again once it cools off or gets lubrication?

I'm having trouble getting my head around the fact that the thrust force to release the clutch can be applied by a disc to 3 points about 6mm square each. It just seems unnatural without another disc on the pressure plate to distribute the load. I suppose the key to it is that the disc & the fingers are spinning at the same speed, yes?

You can call the it a thrust bearing or a clutch release bearing - both words apply. Any bearing that is designed to take axial loads is a thrust bearing, this particular one is a clutch release thrust bearing!

When you put your foot on the clutch, the sleeve is pushed forward until it touches the fingers. It is almost immediately accelerated to the same rotation speed as the pressure plate, giving a little wear on both surfaces - but this is not usually significant. The friction between the fingers and the sleeve is, in normal circumstances, much greater than that of the thrust bearing, so there is minimal movement between the surfaces, just while the sleeve is accelerated.

In this case, the drag on the bearing has exceeded the frictional force between the sleeve and the fingers. Although the sleeve appears to spin freely, don't forget that in operation the bearing has very considerable load on it, and it is quite possible for the bearing to spin freely but drag under load. It does not have to lock, just provide more drag than the fingers spinning on the sleeve face. But it could have momentarily locked - consider if, for example, a chip either from one of the balls or from elsewhere in the gearbox had jammed a ball, but fell out when the load was taken off.

It may be worth noting that when the later diaphragm sping pressure plate is fitted to a S2a, it has a steel ring fitted that the sleeve bears against, although this is not so much to spread the load as to provide a spacer.
John