The MGA With An Attitude
Slipping or Running Free

On 28 July 2007 at 11:43:23 UK time, John Bray, Bedfordshire, United Kingdom wrote:
"After leaving it standing for about 7 years, the clutch appears to be stuck but not in the normal way. You can start the car and select all the gears with or without the clutch pedal down but the car won't move!"

The first suspect is, slave hose is mostly plugged, swollen inside, restricting flow. The clue here is normal pedal force with slow pedal push, but higher pedal force with faster pedal push, and also slow pedal return. The pedal should return as fast as you can lift your foot. If fluid flow is restricted, pedal return force will be limited to the small return spring on the pedal (above your toes). If fluid flow is not restricted, pedal return force will be almost equal to pedal push force.

If the hose is severely swollen inside you may be able to force fluid through it with pedal force, but the fluid may not return at all. In this case the slave pushrod may remain in the extended position, and the clutch will not re-engage. Successive pedal strokes might push the slave farther, possibly popping the piston out of the slave cylinder with loss of fluid. If the fluid returns very slowly, the slave may return to normal rest position with time, and with no loss of fluid. Symptoms then would be, press pedal, engage gear, release pedal and wait. The clutch will gradually engage with lots of slipping, but can eventually attain full grip and normal driving torque.

Other possibilities:
  • Propshaft missing or disconnected? Easy check.
  • Broken halfshaft. Propshaft will spin with engine running in gear (or turn propshaft by hand in neutral) but wheels not turn.
  • Slave cylinder piston popped out end of bore and stuck in extended position (with loss of fluid). Easy replacement.
  • Center broken out of friction disc or popped out the springs.
  • Broken input shaft or gear (maybe never happened before). Broken output shaft (extremely rare).
  • Shifter linkage broken, not engaging any gear.

  • I can't think of any condition that would allow the pressure plate to be disengaged without the pushrod being held.

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