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MG MGB Technical - clutch will not disengage

I recently acquired a 69 roadster that has been off the road for 6 years. I have replaced the clutch master cylinder and slave cylinder and bled the system about 4 times. The clutch still will not release. I thought it might be the braided hose but when the clutch is pushed all the way in the hose does not swell. Tonight I got under my other 69 MGB which operates fine and observed how much the rod coming out of the slave cylinder traveles when the clutch is pushed in. It appears to travel no more then the one on the other car that I cannot get into gear. What am I missing?
Dana Wilson

Dana
Prior posts have mentioned the clutch sticking to the flywheel or pressure plate. Put the e-brake on and try cranking the starter in gear, with the clutch pedal in and see if it will brake loose. Putting the car in 4 th will put the least effort on the ebrake.
Barry
Barry Parkinson

Agreed, if your slave piston is moving the correct distance then you haven't got a hydraulic problem, you've got a friction disc that's rusted onto the flywheel. The starter should free it up.

If it won't, don't pull that engine just yet. You can get some serious torque across that clutch if you need to - and save yourself the agony of removing the whole engine/xmission assembly just to tap free a sticking friction disc.

How to do it: (Worst Case Scenario version)
make sure your rear brakes are adjusted and working. Well.
Check that your motor mounts and u-joints are in good shape.
Raise the rear wheels off the ground.
Run the engine at a good 2500rpm, car in 4th, clutch in.
Since the clutch won't release, the wheels are spinning.
Hit the footbrake. Hard. With the clutch still in. Without letting up on the gas. (You do have three feet, don't you? Find a way. It's either that or drop the car off the jack, your choice, but you've got to stop those wheels cold.)

When the wheels suddenly stop the engine will want to keep going. This *will* free up your clutch, as the engine is revved up a bit and has torque and momentum going for it. I've never seen a clutch so frozen that it can stop an engine from 2500rpm. It sounds scary but it won't hurt anything; in fact the driveline is designed to take occasional shock loads of this sort, as they do occur every now and again in certain driving situations.

Best of luck with it.

-sam
Sam

This all sounds good. I will let you know how I make out. Thanks.
Dana Wilson

With the car up on jack stands I started it up in fourth gear. The rear break cylinders are frozen so I didn't bother using the pedal. With the engine reving at about 3000 I pulled the e-break as hard as I could. Something went bang. The clutch is now working fine. You guys are awesome! Thanks.
Dana Wilson

Oh, and of course I had the clutch in all the way when I did this fun maneuver.
Dana Wilson

I for one assumed that, or the bang would have been something a bit more serious :o)
Paul Hunt

This thread was discussed between 20/04/2005 and 22/04/2005

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