Clutch pedal problem

[altea phil]

I have owned my '55 plate 1.9 tdi Stylance for almost four years now, and have to report that it has covered 85000 almost faultless miles.....however, for the past 4 or 5 days I have noticed that my clutch pedal seems to have gone very light at the top end. I suspected that some air might have got into the system and that it might be leaking fluid, but having removed the air filter box and partially withdrawn the slave cylinder (don't think it will come all the way out without removing the gearbox ), and also having become a contorsionist and got my head into the drivers footwell, can find no evidence of any leak !! I topped the brake fluid up to the max, and initially when I drove it first thing this morning it DID seem okay, but as the day has gone on, it has got worse again. Anyone had a similar problem ??

 

[towcester vag]

it could be the pedal cylinder that is the most common
but i have had the concentric slave cause the same fault
i would change the pedal cylinder first

 

[altea phil]

Cheers TV...the master cylinder looks to be a pig to get out...how much of a job is it, what sort of cost am I looking at for the part, and does it need a pressure bleeder to get it working properly ??

If it is the slave cylinder, does the gearbox have to come out to change it, and again how much is a new slave cylinder ??

 

[towcester vag]

replace cylinder

to replace the pedal cylinder its not too bad
the hard part is removing the feed pipe from the cylinder at the bulkhead under bonnet
beware you dont loose the clip
remove the pedal assy completely and yes use a gunson easibleed to bleed clutch as pumping doesnt clear it properly

 

[altea phil]

Thanks again TV.... will look into doing it soon, but if it turns out to be the slave cylinder, does the gearbox have to come out, as when I loosened it off last week to check for leakage there didn't seem to be enough clearance to fully remove it ??

 

[towcester vag]

if its the slave then box has to come out mate

 

[DerbyForget]

have you considered the fact that your clutch is on its way out? and at 85,000 miles i would say thats pretty bang on the service schedule at (80,000) sorry to point out the obvious but that light feeling you have at the top of the pedal stroke is the free play between your friction material in the clutch and your flywheel getting larger... indicating wear it will slowly get larger until depressing the clutch pedal no longer disengages drive. Its always worth looking at the more obvious faults before you start jumping in head first. hope this has helped

 

[altea phil]

Cheers Derby, but isn't it the other way round......surely the freeplay at the BOTTOM of the stroke will get bigger as the friction plate wears..

 

[Slimy]

You'll never get any freeplay at the bottom of the stroke, you'll always be pushing against the clutch springs even if the clutch is completely screwed.

 

[altea phil]

What I meant was the distance the pedal lifts up before the clutch starts to engage....surely this will increase as the clutch wears, rather than the other way round ???

 

[Slimy]

Ah, I see what you mean now. I have to admit I'm not sure whether the biting point would change, with older cable operated clutches it did used to get higher and higher but I think hydraulic clutches have an element of self adjustment. A bit like the brake pads wearing don't affect the brake pedal function too much. Don't quote me on that though.

 

[DerbyForget]

Cheers Derby, but isn't it the other way round......surely the freeplay at the BOTTOM of the stroke will get bigger as the friction plate wears..

no as the friction plate wears the free play at the top of your pedal will increase... if you imagine how the clutch system works...

pedal operates the master cylinder squeezing fluid down to the slave cylinder which operates a clutch fork... clutch fork presses clutch release bearing onto the diaphragm springs of the clutch thus 'RELEASING' the clutch friction pad. if the clutch friction material is worn the amount that the pedal has to move before starting its effective stroke is INCREASED

i believe that's correct at least that's how the land rovers i work on work and i would imagine most cars work on the same principle but if someone knows more about this system please feel free to jump in

EDIT :- this may just be a first sign that your clutch is wearing. if it starts to slip under heavy load or smells of burning then i would definitely say get it changed as eventually will result in a damaged flywheel

 

[DerbyForget]

What I meant was the distance the pedal lifts up before the clutch starts to engage....surely this will increase as the clutch wears, rather than the other way round ???

it wouldn't be noticeable because as you lift your foot upwards spring pressure would engage the clutch

 

[altea phil]

Thanks again Derby.....I admit it's a good few years since I changed a clutch, but I distinctly remember that the pedal was always at the top of it's travel when the clutch was worn out !
But, these were always on cable operated clutches rather than hydraulic ones, where the cable PULLED the clutch lever, so if it's a hydraulic set-up (as per the Altea) which obviously PUSHES instead of pulling, then does it automatically follow that the pedal will be at the bottom if the clutch is wearing out..

P.S. - Assuming worst case scenario, and the clutch eventually does need replacing, should I change the DMF at the same time, or do they generally have a longer life ??? What sort of cost am I looking at for parts ??

 

[bantamfan]

Snap!

I too have this problem. Did you find what was causing it? My 55 plate 1.9 tdi has 97000 miles but the dmf was changed at about 40000 and i think i remember them saving the clutch had been changed as well. What i don't understand is how the pedal has virtually no slack at the top of travel, at the start of the day and then gradually gets worse. All gears are still engaging with no slippage etc but i am starting to worry!!

 

[altea phil]

Bantamfan (you'll be happy today won't you, after last nights win against Villa ??)...

Still have the same issue (although it doesn't seem as prominent now)...like you say, when it is cold it is fine, but as it gets more use throughout the day (and obviously gets warmer), the pedal seems to go a bit spongy. Again, no issues in changing gear, just a squashy pedal...

 

[bantamfan]

Phil, thanks for the update. I have lots of theories as to what the problem might be, but in the short term i think i will just keep an eye on it. If i get anywhere i will post here.

 

[bantamfan]

Just wondering if anyone else has had this problem. Gear selection is getting harder, so gonna have to bite the bullet and leave it in.

 

[bantamfan]

For anyone interested, the slave cyclinder (at the gearbox) was at fault and replaced. So problem fixed. We did change the master first but it made no difference.