VT928

I have no idea what caused this, need advice. I parked my car as normal, depressing the clutch and shifting it into reverse prior to shutting off the engine and getting out. When I got back in it two hours latter and went to depress the clutch before starting it and found the clutch pedal was fully depressed already. It was all the way down at the end of it travel. My first thoughts were the dreaded blue hose problem. I checked under the car and there was no puddled brake fliud, and the master cylinder fliud level was where is was supposed to be. After scratching my head I reached down into the footwell and pulled the on clutch pedal and it popped right back up. I depressed it several times and each time it worked as normal. So I said WTH and put the car in neutal and fired it up, I slowly depressed the clutch and put it into reverse and backed out of the parking place and drove home, without incident. How could have it in the depressed position? Is there something that can bind or needs grease in the linkage? It is a thirty year old car and I have had it for 11 of them and never done any service on the clutch linkage.

I am perplexed to say the least. Any thoughts would be appreciated

Paul 1980 Euro S Red/lk Lea

jon928se

Paul

The reason it happened is two fold.

1/ The clutch pedal has an assister spring which helps push it down. It is an overcentre action so it shouldn't start pushing until the pedal is depressed a litlle. If it is not adjusted correctly or when there is some wear in the clutch it can be exerting assistance all the time. It is not strong enough to disengage the clutch by itself.

2/ If the master cylinder piston seals are not 100% fluid can leak past them slowly (This doesn't necessarily result in a loss of fluid - the fluid is just transferred back to the portion of the MC that is connected to the reservoir, which is why you have no apparent loss of fluid from the res)

The combination of the the leaking seals and constant slight pressure from the assister spring allows the slow leak to happen over a long period of time which allows the pedal to slowly drop to the floor. Once you pull the pedal back up with your toe the MC refills and provided the leak doesn't get worse the clutch operates as normal. You may find that if you sit with your foot on the clutch pedal for a while waiting at the traffic lights the clutch slowly re-engages by itself.

I think Roger sells clutch master and slave cylinder seal sets but a new slave cylinder is approx $100. JFK knows how to RnR the M/C

Skiviking

Paul, are you coming over to Stowe on Sunday Morning to parade into the British Invasion Show with us? I'm going to swing by and look at the cars on Saturday..anyways....
Thought I'd ask....

VT928

Jon,

Thanks for the info, I looked up the clutch master cylinder repair and it does not look hard to do, and lets face it Jay will be doing it. My job will ce to provide food, wine and unskilled labor. Thanks again for the info

Paul 1900 Euro S Red/Blk Lea

Mrmerlin

just a note make sure to take apart both the new and old clutch MCs to see if the pistons are the same,
the new part has an extended tip this will limit the throw of the new unit and result in a dragging clutch,
the solution is to either use the old piston with the new seal on it or cut the tip off of the new piston
IIRC you need to trim off 4 to 5 MM of the tip. be careful and measure first you dont want the rear seal of the piston to go past the feed port or the MC will leak when its pushed all the way down.
Another consideration is to also check the compressed length of the return spring in the MC,
as it might be a few turns too long and as such when the MC is pressed full the spring then becomes the stop as its compressed to all of the winds touching each other this will result in a cracked spring and then metal shards quickly cutting the new seals and going into the feed line to the slave

robot808

I am sure this isn't the case but, it did happen to me once...
There is a C-clip that holds the pedal to the rod that depresses the MC. Mine once slipped off and the pedal slammed right down to the fire wall because of the spring. I am sure that would only ever happen to me, but might be worth looking at before taking it anywhere.