Queer Clutch Problem - Please Shoot Me...

[SteveSpit]

Can someone please help and shed some light on this for me. I've been fighting it for over a week now and after losing my rag about ten minutes ago I came extremely close to putting my foot through the door.

The gist is, the car has been sat since around either June or September last year (can't remember when last used) anyhow, I can't get a gear. I've had the clutch seize up on it before and managed to free it, however this time, it seems different. I've tried all the tricks in the book to free the clutch off. Running in 4th gear and dropping the rear wheels with the clutch depressed, turning over in gear with just the starter motor, pulling againt handbrake, running at high revs with heavy braking (nice cloud of smoke) but still it won't free off.

The strange thing about the whole scenario is, if I manage to start the car up in gear with the clutch depressed, as I bring the clutch up the engine tone will change. If I pull it out of gear however, I can't select one. My drive has a slight incline, again with the car started in gear and the clutch depressed it will not roll backwards (hence my belief in a stuck clutch), pull it out of gear and it will, as it should, roll down the drive. The issue that is causing me to doubt the clutch is seized, is this change in engine tone (both as clutch lifted and dipped) and lurch (setting off) as I release the clutch. But as mentioned above, if the clutch is dipped, it holds it's position on the drive.

What could it be?

I've had a look at the cylinder, there's fluid in there, a split pin in the pedal to rod assembly and the spacer and circlip are present in the cylinder.
The fact the engine tone changes leads to to think there isn't an issue with air in the system, and the fact the gear box moves freely when in neutral would tend to make me shy away from a sync problem. I'M AT A COMPLETE LOSS!

Also, for some reason known only to the bloody car, it's decided to throw itself off a level stance by around an inch and a half.

Someone PLEASE give me a pointer. Ideally it'll be something I can fix on the drive, tool wise I have pretty much everything under the sun. My only issue really is access, I'm limited to axle stands and ramps.

NB One other thing I have noticed, which may well be unrelated, but I've found if I put the car on the steepest part of the drive, it's easier to acquire a gear and the box seems to work as normal (except reverse, there's a thud and a clang. Bit like a bell being struck. It does this regardless of an incline or not, actually, it's done that for a while.)

[nang]

Are you sure you don't have a hydraulic problem ? Sticking seals in master or slave?
Tony.

[SteveSpit]

It was one of my suspicions, but unsure the best way I could verify it.

[Deleted User]

Buy a haynes manual.

Brakes and Clutches are easy enough to repair and maintain, you need to check that when you push on the clutch pedal it is operating the slave cylinder, you can tell this with the help of another person looking at the slave from underneath whilst the car (car on stands and not just jack) if this is not working get back and let us know.

Rob

[Nick Jones]

Sounds like you have some clutch action but not enough movement to fully clear.

Possible reasons:

- Hydraulic problem (not normally at the top of my list but it was working before layup).  More likely to be the master cylinder IMO.  It might just need bleeding - partial travel is a classic indicator or air in the system (slave cylinder bleed nipple in upper hole!)
- Top of pedal/master cylinder pushrod/clevis pin severely worn
- Fulcrum pin fallen out of the operating arm/bellhousing (common)
- Friction disc damaged
- Friction disc rusted to gearbox shaft (fairly unlikely)
- Spigot bearing partially seized (unlikely!)
- Crankshaft thrust washers dropped out (clutch usually works after pumping or when car is parked nose-down)

Good luck

Nick

[Doug Paterson]

What you describe is a symptom of the clutch plate not fully releasing.  

So it'll work in gear - and probably you could drive it (just) once it is rolling.  But if you knock it out of gear there is enough drag on the clutch to spin the input shaft and cause the problems re-engaging gear.

Pump the pedal repeatedly and you may eventually get just enough movement to get it in gear.

Things which cause insufficient movement.

1.  Hydraulic (air in system or seals) - most likely.
2.  Slave Cylinder needing pushed forwards a bit (the new ones - especially the Alloy ones in my experience - don't fit perfectly).
3.  Wear in the pedal/linkages - its surprising what a difference this can make, but the Pedal Bushes being worn or the clevis hole being worn oval can have  noticeable effect at the slave.

[SteveSpit]

Looking at the replacement clutch cylinders on rimmer bros I've noticed in their master cylinder repair kit there are numerous rubber bushes, a washer and what appears to be a spring washer. Upon inspecting my master cylinder and push rod assy I've noticed there is but one steel washed, held in place with a circlip and a rubber washer that appears to be doing nowt.

There also appears to be what I would consider a considerable air gap between the pushrod end and the cylinder actuator. Would I be right in thinking the bibber bushes are used to reduce this free play and keep the pushrod tight against the master cylinder head?

I'll attempt to pack it as an investigative measure tomorrow and see if it gives any joy.

Now I've calmed down a little and stopped shouting, swearing at it and kicking various heavy and breakable things around the garage I'm able to think a tad more logical!

[nang]

I'd consider replacing complete cylinders. They're not expensive and in my experience, unless cylinder  bores are unmarked and not corroded it's not worth trying to recon them. At least then you'll know they aren't going to be a problem for a while. As an aside do change fluid every 2 years or so. Brake fluid is hygroscopic, it absorbs water and corrodes internal parts.
Tony.

[Velocita Rosso]

Not a million miles from you...
There is a possibility, due to the sound description....that the springs may have gone in the friction disc
When was the clutch last changed/inspected ,out of the car ?
Have you ever stopped an over run on the engine by releasing the clutch when ignition turned off?
When we came back from a Dutch night rally a couple of years ago, we had difficulty in getting gears in Holland.Then boarded the ferry, and when we got off at Hull we had to engage gear prior to starting .Managed to get home, took the box/ bell housing out and the clutch springs fell out on to the floor.

[piman]

Hello Steve,

it does sound as though it is a stuck disc. It doesn't sound as though you actually tried driving the car to free it but just used the brakes,with the car jacked up? If I'm right, try driving the car, as that will load the clutch much more than just the rear brakes.

Alec

[plk21e]

I agree with the previous comment, I recently had to free off a clutch on a morris 1000 and because of its location in a confined space tried the methods you have tried to no avail.eventually with the help of a couple of people pushed the car out so I could drive it to my workshop and it freed of before I got a couple of yards

[SteveSpit]

Have ran the car, under both light and heavy acceleration. The car had a new clutch around 5 years ago.

Velocita Rosso, I haven't done an over run on it no.

[piman]

Hello Steve,

was the running done with the footbrake hard on and the clutch depressed?

Alec

[SteveSpit]

Hi Piman, it was done with the clutch depressed and the brakes on hard enough to lick the car up.

[SteveSpit]

I've also packed out the master cylinder, tried the clutch whilst running and zero improvement. Jacked it up to inspect the slave cylinder, but unsure what to look for to be honest as there are no visible moving parts.

[piman]

Hello Steve,

one way to determine if it is hydraulic or clutch is to jack the rear of the car up securely. Disconnect the slave pushrod from the actuating arm and using a pair of mole grips onto the arm and operate the clutch directly. You will need a helper to sit in the car with the engine running and see if the gear will go in. Obviously the risks in doing this do not need spelling out so you would need to be absolutely certain the car can't drop. Ideally this check would be done on a ramp.

Alec

[SteveSpit]

Ok well I've had some time to investigate today. I loosened the slave cylinder with the intention of pulling it out to check it's operation and prove the hydraulics.

Now bear with me as it may get a bit patchy here as it all goes a bit awry.

In an earlier post I mentioned packing out the play on the master push rod, I had done this before playing with the slave and it gave no difference. However, for testing purposes I left the packing in situ

I couldn't pull the slave out by hand, so to prove the hydraulics I had someone operate the clutch with the pinch bolt undone. The slave moved out of the housing by around 8mm. Thus proving my hydraulics are ok. I reset the slave in it's position and tightened everything back up. Fired the car up, and if I pushed the pedal hard (more than normal, imagine trying to push it through the floor) I could engage first and cycle the box, but still crunching in reverse. This led me to think that perhaps the system needed to be bled. I removed the packing from the master, and sure enough, as I expected, I could not engage or cycle gears (engine running)

With the above theory I stripped the g/box tunnel and attempted to bleed. Now this is where it puzzles me. With the bleed nipple open I got nothing through the system (bear in mind that earlier, it had pushed the slave out of it's housing so had to have pressure). I then moved back to the master cylinder, removed the hydraulic feed and operated the clutch. Now, with a full reservoir I got one good spurt of fluid, after that, just spitting. I removed the master cylinder and pulled the piston, cleaned out the reservoir and checked it free of obstruction. The only thing I noticed that have concern was that the push rod would occasionally kink when operated. I found it to flex in the housing that secured it to the spring. I rebuilt and refitted the cylinder after checking the push rod operated freely and gave a good seal when closed and that fluid flowed when operated.

Again, I tried to bleed the system, but nothing. No pressure against the pedal and the fluid in the reservoir didn't move at all. No amount of pumping the pedal would offer any resistance or build any pressure in the system.

So, what can it be?

Apologies if this reply is a tad lengthy, but trying to convey as much info as possible in the vein hope it answers questions and sparks thoughts.

[Bainzy]

Sounds like either the master or slave cylinder (or both!) needs rebuilding....

[piman]

Hello Steve,

before I had a pressure bleeding kit, I found that with a rebuilt system it took a lot of bleeding. To speed it up I would remove the bleed nipple and have an assistant press the pedal down once, I'd put my finger over the bleed nipple port and my assistant would release the pedal. Doing this for a few strokes would then have enough fluid to bleed normally. Basically pump once and seal the bleed port, repeated several times.

Alec

[Dannyb]

I had a problem some years ago when after a  winters  lay up the clutch pedal was solid. It was the master causing it. For how much the cost it will be worth changing both for new and at the same time rig up a remote bleed into the engine ay for future bleeding.

[Pete Lewis]

there must be some small free play between pedal push rod and the end of the cylinder piston, eg,  if the pedal pivot is seized and the pedal does not fully return or the push rod is too long , you wont get any pressure as the recuperation port seal is held off its seat and the  reservoir feed port  is constantly left open  or its not allowed to open so you never recuperate when lifting your foot off        just a thought   Peter

[SteveSpit]

Right then, after spending one and a half hours last night trying to bleed the clutch I bit the bullet and order a master cylinder refurb kit. I fitted it tonight and started the bleeding process again. Literally within seconds I had pressure back in the system. Took her on a test drive and she ran better than I ever remember. Had a great time and was out for a good couple of hours, felt the familiar grin return!

Now all I need do is figure out why the bloody things started to lean! I'm guessing that the lifting and dropping whilst running the car up has goosed the rear spring. Looks like a trip to spitfire graveyard for a replacement. Anything else that could be causing it? Had a bounce around on the back and the shocks appear to be ok.

[Bainzy]

Seized rear trunnion?

[SteveSpit]

How would I confirm that Bainzy?

[Bainzy]

Unfortunately I'm not sure as I've never actually had it happen! I'm sure there's been threads about it here though, hopefully someone else will chime in.