Engine stalling with clutch pedal depressed when in gear

[crin]

I have a (1.5 petrol) 67 reg Toyota Yaris. Recently it has developed a fault, that when either first or reverse gear is selected the engine starts to judder (unable to knock it out of gear) and eventually it stalls. This doesn't happen all the time. The car has done 80,000 miles so I had the clutch changed but the fault is still there. With the engine running and I select either first or reverse gear and keep the clutch depressed, after about 20 secs the engine stalls. I would be very grateful for anyone's advise on this issue.

Thanks John 

[Bernard Foy]

Was it done by a reputable mechanic?? Did you change the pressure plate?? in what state was the fly wheel in?? was the clutch pedal adjusted correctly??

[crin]

Hi,

Thanks you response. Job carried out by a mechanic with a very good reputation. (I will get back in touch with him on Monday and tell him of the problem). He did have to replace the casing as this was damaged. Mechanics not my strong point. 

 

[MikeSh]

41 minutes ago, crin said:

With the engine running and I select either first or reverse gear and keep the clutch depressed, after about 20 secs the engine stalls.

Could be the master cylinder letting fluid past the piston, so it's gradually engaging the clutch.

[Stevie J]

I would have the car on a level surface and remove the handbrake, then ensure the footbrake is off as well, so the car can roll freely. Engage first gear with the clutch depressed and hold the car in this state with no brakes applied. If the car eventually starts to move forward slightly and the engine speed starts to drop, then the clutch is starting to engage the flywheel for the reason that either the concentric slave (located behind pressure plate in clutch housing) is leaking fluid past, or the master cylinder behind the clutch pedal is doing the same thing. If the concentric slave was replaced when the clutch was replaced, then it is likely that the master cylinder is defective and not holding pressure when depressed and held.

[MikeSh]

35 minutes ago, Stevie J said:

for the reason that either the concentric slave (located behind pressure plate in clutch housing) is leaking fluid past, or the master cylinder behind the clutch pedal is doing the same thing

It's a while since I have been involved in clutches but I'd think that if it's the slave then the fluid will be lost and be noticed - either leaking out under the car or the reservoir level falling, or both. Is that the case if the master is passing, or does it get back into the reservoir?

[Stevie J]

If the fluid is able to leak past the edges of the seal on the piston it wont be lost, just returned back to the reservoir. Sounds like a slow leak past the piston seal so the clutch works if only depressed for a few seconds, before the fluid has had enough time to leak past the piston seal. Problem usually gets worse though quite quickly as the seal fails more. You can get leaks externally from the cylinder as well which would result in loss of fluid from the clutch system fluid reservoir - its stored in the rear half of the brake master cylinder reservoir - all depends on which seal in the cylinder has failed.

[crin]

Thanks to everyone for posting. Had a retired mechanic have a drive in the car. He says definitely either the slave/master problem. Reservoir level all good, so possibly pointing to the master. Will update when car is fixed, hopefully sometime next week.

[Stevie J]

You need to be a bit careful over checking the clutch fluid level - it resides in the brake fluid reservoir, but this reservoir is actually divided into 2 zones inside it, with there being a vertical divider between the front and rear of the container - the brake fluid sits in the front area of the container, and must be full before it overflows into the rear section to fill the clutch master section of the reservoir. It is possible for the clutch fluid to completely drain out and the brake fluid section still to look full when checking the reservoir. You need to look carefully at the very back of the reservoir to see if that section is full or not. This is done so that if the clutch leaks fluid you dont lose the fluid for the brake system, with it being stored in the same reservoir.

[crin]

 

Quick update.

Took the car back and typically it wouldn't fail (ie when I kept the clutch depressed either in gear or neutral ). I could recreate fault later in the day so went back. Plan of attack was that the reservoir was topped right up to the top and that I would return on friday. If level still the same, he said that he would book it in for a master cylinder change. 

I have slightly altered my driving style so not causing me any problems. Not sure whether just to live with it rather than spend more money unless it gets significantly worse,

[crin]

After waiting for several days for the part to arrive, new master cylinder fitted. Tested all ok. Many thanks to everyone who posted on this issue.