New clutch stuck

[llew]

Having "interesting times" with my 1988 90 2.5TD.

Back in the summer the clutch failed - firm pedal but would not release. When I pulled the clutch the clutch plate was broken the damping springs had fallen out. So i fitted a new clutch (AP Driveline formerly Borg and Beck). For good measure new master and slave cylinders (TRW).

So far so good however the splines on the output shaft from the gearbox were almost completly worn away. So I followed the excellent guide on this forum and rebuilt the gearbox with a new mainshaft and a new cross drilled input gear to the transfer box. This took me some time ...

When I refitted the gearbox I tested the clutch release - assuming that I should be able to turn the output shaft by hand with the clutch released. (The gearbox is fine on the bench rotates smoothly and all the gears work fine ...). But the output shaft can obly be turned with the gearbox in neutral.

After bleeding the hydraulics several times with no improvement I pulled the gearbox back out. I half expected to find that I had put the clutch plate in the wrong way round. But the only issue was that the clutch plate was lightly stuck to the cover plate by light corrosion. I'm a bit dubious that this was enough to stop the clutch from releasing given the leverage of the cover plate mechanism.

But does this seem likely?

The flywheel is clean, smooth and flat. The spigot bearing looks good and matches the diameter of the gearbox input shaft. The clutch plate was the right way around and had been centered with the gearbox input shaft. The new release bearing came with the clutch and matched the size of the old one. The fork looks almost new no sign of cracking or distortion.

What else should I check?

[dailysleaze]

Maybe check that the pedal is adjusted correctly and it operates the slave cylinder against your thumb pressure holding it in, and maybe double check the slave cylinder part number as there have been lots over the years and if incorrect it may not push far enough

[steve b]

If the plate was stuck to the flywheel , no matter how lightly, releasing the pressure plate won't break the 'stick'

I'd be inclined to reinforce the arm at the pivot seat while it's off and then get it together and use it as soon as you can

Good stuff doing the mainshaft replacement

cheers

Steveb

[llew]

Thanks guys.

Steveb you are spot on.

Just a tiny amount of corrosion. Moral of the story should have sorted the gearbox out before fitting the new clutch.

Just need to put the transfer box back in and I'm away.

Cheers

llew

[Team Idris]

The old-boy trick was to park stuff up with a stick on the clutch pedal to keep the clutch 'open'. I don't think modern vehicles would take to that fix though

[simonb]

As mentioned elsewhere, always check the setting of the master push rod as well after changing the clutch:

Bottom of pedal must be 140mm from floor and then adjust push rod on master - there needs to be 1.5mm of free play between the end of the rod and cylinder piston. Pedal should be able to be depressed at least 6mm before there is movement of the master cylinder input piston.

[cookie64]

As mentioned elsewhere, always check the setting of the master push rod as well after changing the clutch:

Bottom of pedal must be 140mm from floor and then adjust push rod on master - there needs to be 1.5mm of free play between the end of the rod and cylinder piston. Pedal should be able to be depressed at least 6mm before there is movement of the master cylinder input piston.

thats some interesting figures? where did you find those out? when i rebuilt my clutch system i just kind of set the height of the clutch pedal to be similar to the brake pedal (although i think this may be a tad high from when i redid the brake system)

[simonb]

From the official LR WSM.

[western]

search this forum for 'clutch pedal adjustment' I posted the WSM extract ages ago.