11 replies to this topic

[The_Doc]

Fully rebuilt engine, verto clutch, new clutch plate, but didn't change the diaphragm spring plate thing. New release bearing, rebuilt slave and master cylinder, lapped flywheel onto the crank nose. New thrust bearings and crank end float checked. Also clutch end stop nut fully backed off.

But...the clutch pedal only goes halfway down. It then stops pretty firmly. The clutch seems to disengage (checked by rolling if back and forth in gear), but it's definitely not right.

The brief couple of times I drove it around the drive it definitely didn't feel like this. I've searched everything I can find on here and not seen anything similar.

It's almost like the diaphragm spring has lost all it's spring and bottoms out. But I don't understand how that can happen when I haven't driven it and it didn't do that before.

All advice welcome!

[The_Doc]

Pictures attached

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[coopertaz]

guess you forgot the 'top hat' then!!

[The_Doc]

I took the top hat off before taking the picture!

[Ethel]

Friction plate the right way round 

[GraemeC]

Hose breaking down internally and acting as a one way valve. Slave therefore getting pumped up and internal piston hitting end stop/circlip?

[The_Doc]

Friction plate the right way round

Checked that. Not possible to do it wrong actually from what I can see. Thanks though.

[The_Doc]

Hose breaking down internally and acting as a one way valve. Slave therefore getting pumped up and internal piston hitting end stop/circlip?

Already fitted a new hose, also slave has no circlip, I can push the piston right out with the pedal. It's 100% a mechanical issue.

I've also just replaced all of the lever arms, linkages etc. No difference.

I think the pressure plate is worn but no one I talk to seems to think that happens.

[The_Doc]

Had some developments. Fitted the old plate and clutch feels fine. Old plate was 7.1mm, new one is 8.3mm thickness. So should I skim the flywheel? Is 1.2mm too much to skim? Can you skim 0.6mm from both the flywheel and pressure plate?

[stoneface]

Probably nothing to do with it, but might be worth a read as not all replacement parts are fit for purpose.

https://www.theminif...ust-sleeve-fit/

 

[Ethel]

If changing the plate makes the difference then it must be the plate.

 

All I can think is the extra disc thickness means the diaphragm is compressed more so there's less travel before the pressure plate can bottom out on itself. If that happened you'd be pressing the whole assembly against the thrust bearings via the spring fingers so it should feel a little spongy. The throw out stop could be adjusted to stop that, but you'd still have the high pedal.

[The_Doc]

If changing the plate makes the difference then it must be the plate.

All I can think is the extra disc thickness means the diaphragm is compressed more so there's less travel before the pressure plate can bottom out on itself. If that happened you'd be pressing the whole assembly against the thrust bearings via the spring fingers so it should feel a little spongy. The throw out stop could be adjusted to stop that, but you'd still have the high pedal.

I think you've summarised it perfectly. Thanks all!