Solid clutch pedal

[AlanL]

Has anyone else experienced an issue with a clutch pedal suddenly going solid and can't be depressed ?

The last works done to that area was gearbox oil refilled and the prop shaft off to replace the seals.

I reversed the car,Spit 1500, then drove a few hundred yards and the pedal suddenly went solid.

There is plenty of fluid and I cannot see anything wrong with the linkage by the master cylinder.  

[debsdonna]

possibly the bar from the front of slave cylinder slipped out and jammed .just a thought?

[davidb5964]

I think you need to get to the slave cylinder, undo the bleed nipple and press down on the pedal expecting a flow of fluid. If that's OK the top end of the system [pedal links and master cylinder ] should be OK, then slave out and see if it has jammed, sat here at work as a quality engineer for a clutch manufacturer with a spit clutch in front of me and struggling to see how one could jam without the driven plate breaking up,Not had one back like that for as long as I can remember, but always a first time.

[AlanL]

Many thanks both,I will investigate in the morning.

[RobPearce]

If the pedal connection to the master cylinder is not the original/correct gudgeon pin - for instance, if somebody has replaced it with a bolt and nut - it's possible (just!) for that to come loose, slip out and catch on something. Unlikely but easily diagnosed by inspection.

[heraldcoupe]

This symptom can be down to the master cylinder's internal spring breaking. When solid, the clutch would be disengaged if this is the case,

Cheers,
Bill.

[AlanL]

Well initial investigation is that the master cylinder is ok, we opened the bleed screw on the slave cylinder and the pedal pressed,loosing all the fluid in the process!

Thought I had some more but can't find it, so will do that tomorrow.
However, while the engine is running,it is possible to go through all the gears,but they are not engaging,is this because there is no pressure in the clutch,so the friction plate isn't engaging ?

Never messed with clutch /g/box before !

[davidb5964]

ummm

With the clutch pedal up, or the bleed nipple open, or pipe disconnected the clutch should be at clamp position, if the box is free to rotate in gear with the engine running then the cover assembly could be depressed, so could be a few things.
i will pm you my number here until 9.30pm
Dave

[davidb5964]

So my thoughts on what it could be:
1.Slave cylinder jammed in its extended position.Causing thrust bearing to be pushing down on the diaphragm fingers leaving driven plate free to rotate.
2. Diaphragm spring broken but that does not usually jam in the disengaged position.
3. Release arm jammed at bottom of the stroke. Same result as no.1
4. Driven plate stuck on input shaft spline but unlikely to suddenly stick.

[djw113uk]

It will be the clutch slave cylinder jammed at the end of its travel. This often happens after a prolonged lay-up!
Be careful taking the slave out as all the force of the clutch will be trying to push it out of the clamp as you undo it.

[davidb5964]

A good point
Dave

[system6]

DJW.....is correct on what he,s saying ..had the same problem with my gt6.....what i did was to give te peddle some whelly...short sharp heavy presses of peddle until slave piston is free to move.......

[Pete Lewis]

The withdrawl lever pivot pin has most likely dropped out , this allows the throwout to over travel the slave runs out of travel and you cant depress the pressure plate  
its a very common failure
if you look at the clutch hsg drivers side youmcan justnsee thenhole the pin fits in
it has no head , itsnlocated by a tolerance ring wichnis a crinkle spring steel bush , this breaks up the pin drops out    its a regular fault,    
replace with a pin or bolt (not a setscrew) with a head on it ...cant fall out

pete

[Don Cook]

On my GT6 the pivot pin became dislodged, similar symptoms. Box out job, not too difficult.

[Pete Lewis]

On a 4 cyl its possible to poke and prod the lever into position to realign the hole and drop a  bolt in from the top without removing the box
This will fix it till you do a full repair, with new tolerance bush and a pin with a head on it
amd a  olt with a plain shank will last years never to fall out again.

heck Don  it takes a bit for the sperical post to jump out on the 6 cly,  thats unlucky

on many 6  cyls the throwout bearing is too thin at 15mm (should  be 19mm)and the 6 pot post needs to be a bit longer to keep the lever ratio correct  like add a couple of washers under it to stand out a bit more.

[Velocita Rosso]

Quoted from Don Cook

On my GT6 the pivot pin became dislodged, similar symptoms. Box out job, not too difficult.

You`re used to that!

[AlanL]

Thanks to davidb5964 for the phone advice and everyone else also.

We removed the slave cylinder and there was a resounding clunk!

So I guess something inside seized.

[efp]

All on tenterhooks here, waiting for a resolution..
My money was on a dropped arm pivot pin, but now I don't know.
Dropping the box is fiddly, but not a huge job on the overall scale of things. Tho getting it back aligned can be a faff if you're unlucky.. See other posts. Element of luck and patience involved.
Personally I'd be inclined to open it up and check it all out if your furkling with the slave isn't conclusive. And if you do choose to go that far you may as well put in a new clutch assembly, release bearing, crinkle bush and headed pivot pin if you are in any doubt on any of them, not a job you want to do again for a while, and the parts aren't that expensive.
Just my $0.002.

[efp]

ie, not even worth $0.02... 🙂