Curious clutch/gearbox problem...

Hxc

Hxc

Hxc

Soldato
Joined
29 Oct 2004
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London
As of late I've been having some very stiff and clunky gear changes which have got progressively worse and then occasionally disapeared until tonight where it's hit it's worst. Car would not go into gear without superhuman force (althuogh no crunching). I pulled over, stopped and started the car again, with it in gear, clutch to the floor, and it stalled instantly, implying the clutch was dead. Eventually I got it into gear and drove home with just a slightly stiff gearchange but otherwise normal drive. At home starting in gear proved problematic once again, but after the car was left for an hour or so, we could start it in gear, change gear (albeit stiffly) move the car about, and test for the clutch slipping (heal on accel, toe on brake, raise clutch) and there is no slip.

Any clever mechanical folk got any ideas?
 
First thoughts are that the clutch isn't disengaging properly - can you change gear by rev-matching? It could be something amiss with the master cylinder, are you losing clutch hydraulic fluid at all?

If it isn't that then perhaps something is amiss in the selector (forks, linkage, something like that?) but I can't see why that would be intermittent...
 
How did the pedal feel? Is it cable or hydraulic? Maybe something seizing - pressure plate/springs perhaps?
 
Can change gear by rev matching, yes, I purposefully avoided as much clutch useage as possible on the way home and upshifted without clutch. Pedal feels perfectly normal and it can be seen that the hydraulics moving the clutch (or at least trying to!) by looking under the bonnet and pressing the pedal.

Car is an old mini.

Gearbox oil is shared with the engine, which level is fine, I topped it up 2 days ago.
 
Hxc said:
Can change gear by rev matching, yes, I purposefully avoided as much clutch useage as possible on the way home and upshifted without clutch. Pedal feels perfectly normal and it can be seen that the hydraulics moving the clutch (or at least trying to!) by looking under the bonnet and pressing the pedal.

Car is an old mini.

Gearbox oil is shared with the engine, which level is fine, I topped it up 2 days ago.
Click to expand...

It is a bit odd that the pedal still feels exactly the same as before, that would suggest that the resisance is the same as when the clutch is operating normally which is a bit strange (to me!).

Before you start taking stuff apart, can you see if the clutch pedal operates the full range of movement on whatever part it is you can see moving in the engine bay? If that is moving normally, the problem lies after that in the system - if not, it is before.

My bet is on some form of failure in the hydraulic bit of the system be that air in there, failing seals on one of the cyls, hose which is balooning under pressure or something like that.
 
Actually thinking about it, and from experience (intermittent and not this serious but I replaced it anyway), a failed slave cylinder (or master cylinder I guess, but not as common a problem) would cause these symptoms if it's not disengaging enough. I think DRZ may be right
 
If the clutch did feel different it was not significantly so, it's certainly not slipping at all or anything. There's been no change in bite point or anything like that.

It definitely is operating at full range of movement, at least with the engine off and when I am able to start in gear, I have not checked when it's unable to get started in gear as it's intermittent!

Thrust bearing is a fair call, there has been the odd rattle at idle when the clutch pedal is up and it's not in gear and I've always suspected it might be the thrust bearing. 65k is the supposed milage but I'm fairly confident this is an older engine than what originally came with the car so it could be more than that on the first clutch or the like.

Thaaanks to everyone who has replied thus far; you've been more use than the bloody Mini forum :D
 
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mine went in a similar way a few months ago, release bearing died. dont keep driving it as the bearing will fall apart and you'll get more damage as a result.
 
agree with drz. when the clutch "died" on my golf years back, pedal felt fine, it had played up for a while failing to disengage then eventually wouldnt disengage at all. part of the spring mech on the friction plate fell apart and jammed the mech
 
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