Clutch problem - Any thoughts?

BeardyGit

Hi all,



Time to tap into the collective wisdom of the boards/motors afficianados. I'm having a headache with the clutch on my old volvo. It's an early '97 V40 - confirmed to have an actual Volvo 1.8 engine, not the GDi...So that's one thing that's not as bad as it could be. I believe the gearbox is a renault 19 derivative - Reverse is forward and left. Sorry this is a bit long, but want to give the full rundown....

The issue is that the clutch pedals bite point has been rising over the last 6 months, and is now at a point where it's only got about an inch of 'bite'....I've almost got my foot off the clutch pedal before I feel it's engaged. I've also got the feeling it's been slipping a bit lately in second/third gear when driving uphill and with some load in the car. I've driven enough ropey old heaps to know when a clutch is worn, and this definately feels like it. The old handbrake stall test didn't work either - The stall took too long for my liking.... I also get a bit of a shudder on take off.

Now, all that points towards a clutch problem, at least it should to the best of my knowledge. Except it ain't the clutch - I spent hour after hour last night to pull the clutch out and see what was what. The pressure plate looked just fine to me. The clutch plate had minimal wear and the release bearing was in full working order....it also wasn't contaminated with oil and there weren't masses of dust built up in the spings on the clutch plate. I'm disgusted and somewhat baffled. I've swapped in the new kit I bought anyway (a LUK heavy duty kit) so I know it's been done, but I'm left wondering what else could be causing the problem....

I'm open to suggestions folks. It was suggested to me that maybe the hydraulics needed bleeding, but it looks like the slave is moving the actuator arm through a full range of motion (although I could be wrong of course).... I've also been told the clutch pedal shouldn't need to be adjusted, but this doesn't quite sit right with me as I'd always though service intervals included adjusting the clutch pedal to take up wear in the clutch for example.

Sorry it's so long but wanted to give some details to you folks,

Thanks,

Gil

cabrwab

:eek:More knowledge then some on here! Sorry can't help but I would not have the balls to touch a clutch.
Could the gearbox but the problem?

gonna get slated for this!

Dermo123

Hmmmm. Interesting one. The bite point on the clutch rising over six months seems very fast rate of wear unless you have been towing caravans up and down the Dublin mountains for the last six months.
The fact that the pressure plate and clutch plate are in good nick (I aasume you compared old and new) has to indicate some issue with an adjustment between the pedal and the release bearing.
When you put the new clutch kit in, did the bite point go back down? If not then you will have to start eliminating the other possibilities so bleeding the hydralic fluid and replenishing should be next. Also check for evidence of leaks.
There also might be a self adjusting mechanism at the clutch pedal that needs checking? If this is also based on what was in the Renault 19 then I have first hand experience of this giving problems for me but in a different way.

slimjimmc

If all else fails you could check if the release fork was twisted or bending and is it pushing/pulling the release bearing evenly on both sides. Means yanking out the box again :eek: so it's only a last resort.

Henry Ford III

Slave cylinder seals may be gone.

blackbox

slimjimmc wrote: »

If all else fails you could check if the release fork was twisted or bending and is it pushing/pulling the release bearing evenly on both sides. Means yanking out the box again :eek: so it's only a last resort.

+1

If the master or slave cylinders were leaking/passing pumping them might improve the situation and it would start to engage if you held down the pedal for a long time.

Before pulling off the gearbox again I would try bleeding the hydraulics in case there are some air bubbles in there.

the merchant

Definitely could be the fork. You say the bearing looked ok but did you change it? Just want to make sure. I take it the flywheel surface was also ok???

I've personally never seen the slave cylinder cause the clutch to slip, just go the other way i.e. not clearing for the gears etc ... mmm, might the piston not be going into the cylinder all the way?

Sorry, i've ruled out nothing ;(

BeardyGit

Thanks for the replies lads. There's no sign of leakage or fluid loss anywhere, so I'll have to consider other possibilities.... The fork would be a good one alright, but I had a close look at it when I pulled the old bearing, and again last night - I kept the old bits 'til I figure this one out. Looked fine, and the wear on the back of the bearing where it engaged is even too. Flywheel surface was fine too when I checked it the night before.

Back to basics I guess - I'll bleed it tonight and see how that goes (if the rain holds off)

I'll keep ye posted,

Gil

S.I.R

it could be the cabel or the gears themselfs... but if the clutch is in perfect nick how could it be slipping ?? i say release bearing and a cog or two are wreaked...

imo...

Dermo123

S.I.R wrote: »

a cog or two are wreaked...

That is some diagnosis

BeardyGit

There are no gears. It's a clutch issue, not a gearbox issue. There is also no cable as it's a hydraulic clutch. Hense the reference to bleeding the hydraulics. Thanks for the suggestions anyway but I'm looking for more than a wild guess... I've covered off the actual clutch/pressure plate/flywheel/actuator/release bearing having faults, so I'm looking at more obscure and overlooked possible causes.

Hydraulics fluid and cylinders are next on the hit-list I reckon.

Thanks,

Gil

Henry Ford III

Gil_Dub wrote: »

...Hydraulics fluid and cylinders are next on the hit-list I reckon.

To get air in the system only requires a tiny tear in a seal. Might not be obvious at all.

I reckon change the slave cylinder (cheap) and use an Easybleed to purge the system of air.

cormac_byrne

My theory

As far as I know hydraulic clutches are self adjusting (references to clutch adjustment at servicing are for cable clutches)

Pressing the pedal pushes the master cylinder piston into the cylinder, which forces fluid into the line, which ejects the slave cylinder piston, which pushes a lever (fork), which pushes the release bearing against the pressure plate to pull the clutch away from the flywheel. i.e. to disengage it

to disengage the clutch you need 2 things
sufficient travel to push the bearing far enough
and enough force to overcome the springs in the pressure plate

You know all that and it works ok.

The problem is in the reverse action.

Without the pedal pressed the clutch should be pressed tightly against the flywheel by the force of the springs in the pressure plate. i.e. engaged

The usual reason for clutch not engaging is simply a worn clutch, or slippy dirty clutch. You've ruled out both of these already.

It could also be a worn out pressure plate. You don't say if you also replace this along with the clutch (a mechanic once told me it's good practice to do the two at the same time) I don't know if it would always be apparent from a visual inspection, perhaps a Clutch repair place might have a means of testing one.

If it's not the pressure plate then there must be something else preventing the clutch returning to it's normal position.

I'm wondering if possibly the slave cylinder piston could be getting stuck at a certain point in the cylinder. i.e. not retracting fully.

It's retracting enough that the clutch gets some grip, but not enough under load, hence the slipping etc...

Initially in this scenario you might expect that the pedal too would not be returned to it's correct position and hence this condition would be easy to spot.

** However ***

As far as I know there is a spring which pulls the pedal back into position.
this pulls the master cylinder piston back causing the master cylinder to refill with fluid. Normally this would be the fluid returned from the slave cylinder, but if this is stuck the fluid will come from the reservoir.

This flow from the reservoir is supposed to act as a self adjusting mechanism,
but in your situation, I think would raise the biting point

Dermo123

Now there is an explanation that makes some sense.
I believe the OP said he put in a clutch kit which I believe would include a pressure plate??? So a sticking slave cylinder as you described would be a very reasonable explanation for the symthoms described.
Did you notice any signifigant drop in the clutch fluid resevoir level during the six months the clutch bite point was rising? Maybe that is not easy to check but a bit of messing with the hydrolic system that controls the clutch is probably on the cards.
Let us know how you get on

BeardyGit

Okay, so I've bled that bastid and it's still the same. Took the opportunity to 'upgrade' to DOT 5.1 while I was at it.

Still no joy :rolleyes:

I've managed to find the Haynes manual for it (I knew I had it somewhere) and it has a bit about adjusting the pedal, but it looks like it's only adjusting the reach.

I'm thinking I might have to hand it to a 'real' mechanic to sort it at this stage.