clutch pedal sticking

[landroverbodger]

i have a 2012 superb diesel. the clutch pedal has been sticking down on and off for a few months. it has lost no fluid  it will do thisa few times then be ok for a few days. before i start changing parts is it possible this could be something like a sticky pedal pivot needs oiling. i dont feel like changing the clutch outside at this time of year. 

[landroverbodger]

the car has done 175000 miles no idea if or when the clutch has been changed.

[TasMan]

This happened to my 2014 Superb and was early failure of the clutch slave cylinder.  I noticed the clutch seemed to be slipping for a few days before then one morning the pedal dropped to the floor and clutch operation failed.  Required new clutch, slave cylinder etc @ 4 years old....

There was quite a lot of fluid loss present when the AA guy turned up, had to be recovered to the garage for repair.

[landroverbodger]

i have had no clutch slip or fluid loss. 

[bigjohn]

On 11/01/2024 at 07:03, landroverbodger said:

i have a 2012 superb diesel. the clutch pedal has been sticking down on and off for a few months. it has lost no fluid  it will do thisa few times then be ok for a few days. before i start changing parts is it possible this could be something like a sticky pedal pivot needs oiling. i dont feel like changing the clutch outside at this time of year. 

Which engine do you have?

 

You could try bleeding the clutch / brake fluid as there is a valve within the slave cylinders (different depending on the engine) that can rust if the fluid has moisture in it (Brake fluids are hygroscopic - absorb water).  The next plan of action depends on if you have a concentric or external slave cylinder which varies depending on the engine.

 

 

 

 

Edited 12 January by bigjohn

[landroverbodger]

2.0 diesel 

[Tropheus]

Happened on my wife's 2013 a couple of months ago.  The clutch went to the floor and stayed there.  It was the clutch master cylinder.  We did the slave cylinder at the same time, given the low cost, to ensure the problem stays away for another 200k miles.

[bigjohn]

If 2.0 diesel then it's a concentric clutch slave cylinder that's a gearbox off big job (it's the 1.6 that has an external slave - easy job) so I'd try a clutch fluid refresh / bleed first then if that doesn't work replacing master cylinder is possibly the next option.

 

If that doesn't work then it's a gearbox off job so you might as well change the whole clutch, slave and possibly even Dual Mass Flywheel whilst the gearbox is off - not cheap though😟.

Edited 13 January by bigjohn

[landroverbodger]

i just hope it lasts till the weather warms up its too cold to remove gearboxes outside at this time of year. the strange thing with this is if i lift the pedal it will sometimes work for a week or two without sticking again. it feels like a sticky  spot on the pedal pivot. 

[bigjohn]

5 hours ago, landroverbodger said:

i just hope it lasts till the weather warms up its too cold to remove gearboxes outside at this time of year. the strange thing with this is if i lift the pedal it will sometimes work for a week or two without sticking again. it feels like a sticky  spot on the pedal pivot. 

 

Try the bleeding - that's easy. I had issues with the pedal sticking and my local independent tried this. The fluid came out a funny colour and it's been ok since. There is a "dump" valve to protect the clutch against rapid release that can rust internally if the clutch/brake fluid has water content. Service replaces brake fluid every two years after the first change at three years but doesn't include the clutch even though it shares the same fluid reservoir.  I now always ask for clutch fluid change when the braking system has a fluid change.

 

 

[landroverbodger]

a bit of an update. i have just changed the complete clutch including changing to a single mass flywheel.the old slave was leaking when under pressure . its all done except bleeding it as i need a new pressure bleeder and all the shops are  closed today.  

[bigjohn]

Funnily enough I've just had a new clutch as well - I detected a slight slip when dropping into 6th accelerating onto a motorway from a "er slip" road.  Probably would have been ok for a while but as I'm planning a long European trip this summer though I better get it sorted. Whilst gearbox was being removed etc I asked for a new external slave, clutch fork and a change of gearbox oil. Flywheel was ok and it's a Single Mass anyway on the 125pc 1.4tsi.

 

[chimaera]

1 hour ago, landroverbodger said:

a bit of an update. i have just changed the complete clutch including changing to a single mass flywheel.the old slave was leaking when under pressure . its all done except bleeding it as i need a new pressure bleeder and all the shops are  closed today.  

You probably won't want to hear this, but single mass flywheel is a really bad idea. These engines were designed specifically around the DMF and the crankshaft is lightened since it doesn't have to withstand high shock and vibration loads. They're not strong enough to last long term with a SMF.

[J.R.]

On 13/01/2024 at 10:06, Tropheus said:

Happened on my wife's 2013 a couple of months ago.  The clutch went to the floor and stayed there.  It was the clutch master cylinder.  We did the slave cylinder at the same time, given the low cost, to ensure the problem stays away for another 200k miles.

 

I think you have got that backwards.

[J.R.]

3 hours ago, landroverbodger said:

a bit of an update. i have just changed the complete clutch including changing to a single mass flywheel.the old slave was leaking when under pressure . its all done except bleeding it as i need a new pressure bleeder and all the shops are  closed today.  

 

My experience is that they dont leak but draw in air which concurs with your statement that there was no fluid loss, I bet you did not see any fluid in the bellhousing.

 

The air is drawn in at the O ring joint between the two plastic parts of the cylinder, I'm pretty sure replacing that alone would effect a 100% repair but who is going to take the risk when the component is relatively cheap and so much work to get to it? - I certainly didn't but I did track down an early revision one piece alloy slave cylinder, the car is a keeper and I do not want to do the job again.

 

You do not need a pressure bleeder, open the thumbturn bleed nipple and gravity will do the job for you in a matter of seconds, if you replaced the master cylinder as well then a little longer.

 

Yes, I know you are probably going to link to a VAG document saying to use a pressure bleeder but I know of what I speak having done the job rather than being a keyboard expert, I've done it all too many times at the side of the road because towards the end I could only drive 5 miles in urban conditions before losing the clutch again, I could do it at the side of the road in 2 minutes flat including removing the air filter and intake piping for access, simply by gravity, no pressure bleeder needed, its a very simple system and the master cylinder has no valves, one piston and one seal, as complicated as a bicycle pump!

[bigjohn]

1 hour ago, J.R. said:

 

I think you have got that backwards.

 

Why? I think the 1.6 diesel is fitted with an external slave cylinder so not a gearbox off job and cheapish to do - especially if you are doing it at the same time as other clutch hydraulics.

 

The 2.0 diesel has a concentric slave - now that's a big gearbox off job.

 

 

Edited 31 March by bigjohn

[landroverbodger]

2 hours ago, J.R. said:

 

My experience is that they dont leak but draw in air which concurs with your statement that there was no fluid loss, I bet you did not see any fluid in the bellhousing.

 

The air is drawn in at the O ring joint between the two plastic parts of the cylinder, I'm pretty sure replacing that alone would effect a 100% repair but who is going to take the risk when the component is relatively cheap and so much work to get to it? - I certainly didn't but I did track down an early revision one piece alloy slave cylinder, the car is a keeper and I do not want to do the job again.

 

You do not need a pressure bleeder, open the thumbturn bleed nipple and gravity will do the job for you in a matter of seconds, if you replaced the master cylinder as well then a little longer.

 

Yes, I know you are probably going to link to a VAG document saying to use a pressure bleeder but I know of what I speak having done the job rather than being a keyboard expert, I've done it all too many times at the side of the road because towards the end I could only drive 5 miles in urban conditions before losing the clutch again, I could do it at the side of the road in 2 minutes flat including removing the air filter and intake piping for access, simply by gravity, no pressure bleeder needed, its a very simple system and the master cylinder has no valves, one piston and one seal, as complicated as a bicycle pump!

the leak was pressure escaping when i squeezed the old slave with the pipe connection blocked. i had no luck with gravity bleeding or vacuum.  i did remove the bleed valve and clean it out with brake cleaner to check it was not blocked.

[J.R.]

3 hours ago, bigjohn said:

 

Why? I think the 1.6 diesel is fitted with an external slave cylinder so not a gearbox off job and cheapish to do - especially if you are doing it at the same time as other clutch hydraulics.

 

The 2.0 diesel has a concentric slave - now that's a big gearbox off job.

 

 

 

OK, I see the error of my assumption!

 

On the 2.0tdi it's relatively cheap to replace the master cylinder compared to the slave as you point out so most people, myself included tackle that first in the hope they might dodge the bullet, the bullet that they usually end up biting!

[J.R.]

2 hours ago, landroverbodger said:

the leak was pressure escaping when i squeezed the old slave with the pipe connection blocked

 

Interesting, so was it drawing in air like I proposed or did you see evidence of fluid leakage?

 

I wish I had tried that, maybe under water to confirm that it was the O ring joint.

 

The joint on the old cylinder was floppy and the seal flattened on inspection, where the pipe exits the bellhousing it was a large clearance hole and the pipe had been flapping around with engine vibration, extension pipe oscillating slave cylinder body fixed and cannot move = differential movement and wear.

 

I thought mine may hav been missing a grommet, I was not the first to have had the gearbox out, but I could not see a part number for it, maybe they have reduced the clearance on later models, I used PU glue to fill the gap but with a solid alloy cylinder there is no O ring joint to fail but equally I did not want the pipe fatiguing.

[andrehj]

21 hours ago, landroverbodger said:

a bit of an update. i have just changed the complete clutch including changing to a single mass flywheel.the old slave was leaking when under pressure . its all done except bleeding it as i need a new pressure bleeder and all the shops are  closed today.  

Completely agree with @chimaera above. Changing the flywheel to a single mass version is a very bad idea.

First: The original double-mass one lasted 175.000 miles. If the new one has the same lifetime, that should be more than enough for the lifetime of the car.

Second: A dual mass flywheel dampens vibrations, especially at low RPM. The vibrations cause premature wear, not only on the crankschaft, but also in the gearbox, The gears and bearings are now subject to all vibrations caused by the engine, something theys are not designed for!

Third: These vibrations also lower the comfort level of the car.

Why do you think they invented dual mass flywheels in a business where every penny counts?

 

Edited 1 April by andrehj

[landroverbodger]

its now all up and running. it took about two minutes with an easybleed. as for if a solid or dual mass is best time will tell i only do about five thousand miles a year in this car.  

[TasMan]

Interesting thread, when my 2.0TDI (CFFB engine) slave cylinder failed, the pedal stuck to the floor and there was quite a bit of fluid leak from the bellhousing.  

Bugger of a job on a 4x4 with extra labour to dismantle....I'm hoping to run the car a while longer and just hope I don't have this issue again.... ££££££ !!!