Hi all,

 

My clutch pedal occasionally sticks half way back up the travel after changing gear. The clutch otherwise appears to work fine (noticed that it didn't follow my foot back up, and had a few hard gear changes). First few times it has done it it seemed to be when I was hard braking just prior to changing gear. It does it probably once very two or three journeys. 

 

My brake fluid is a little overdue being changed, presumably the Octavia uses the same fluid for both systems? I've not noticed a drop in the brake fluid at all. I'm going to check the pedal pivot and springs (and relube if necessary).

 

Is there any other wisdom newer than the previous posts where it is the slave cylinder (and split design/bad o ring)? And any downside about driving it until it gets much worse?

 

Cheers,

 

I had a similar problem with my Superb mkII a while ago.

 

Get your brake fluid changed including bleeding through the clutch slave cylinder. There is a dump valve within the clutch hydraulics to protect the clutch but if the fluid in the clutch has not been replaced at the same time as the brakes in the past it can rust etc causing sticking. Sometimes replacing the fluid helps, well it did on my mkII 1.4tsi Superb - the fluid came out a grotty colour! It was ok afterwards but later when the clutch wore out I had the slave cylinder changed as well.

 

PS yes it's a common fluid reservoir between brake & clutch.

 

Does yours have an external or internal/concentric clutch slave cylinder?

Edited 2 August, 20241 yr by bigjohn

Hi bigjohn,

 

I believe it's an internal concentric type looking at parts diagrams.

 

I'll get the fluid bled, hopefully it's something I can tackle myself!

 

Cheers,

Check simple things first is any trapped around the clutch peddle. Check that fluid level. Go for the easy things fist.qhats the millage on the car

On 02/08/2024 at 23:30, bigjohn said:

There is a dump valve within the clutch hydraulics to protect the clutch but if the fluid in the clutch has not been replaced at the same time as the brakes in the past it can rust etc causing sticking

 

Its known as the clutch peak torque limiter, in operation it slows down the speed at which the clutch is released, if you change gear too quickly or sidestep the clutch to spin the wheels the clutch will slip protecting the transmission, it has no metallic parts and cannot rust.

 

The master cylinder has no metallic parts either, it has a plastic piston in a plastic bore, even the pushrod is plastic, there is a sintered toroidal magnetic ring to actuate the clutch position hall sensor, any metallic residue from the brake/clutch reservoir will become attached to and held by this.

 

The problem with the intermittent sticking clutch pedal which will soon develop to failure requiring more and more frequent bleeding is air drawn into the system through the O ring joining the two plastic parts of the concentric slave cylinder without leaking any fluid.

9 hours ago, J.R. said:

 

Its known as the clutch peak torque limiter, in operation it slows down the speed at which the clutch is released, if you change gear too quickly or sidestep the clutch to spin the wheels the clutch will slip protecting the transmission, it has no metallic parts and cannot rust.

 

The master cylinder has no metallic parts either, it has a plastic piston in a plastic bore, even the pushrod is plastic, there is a sintered toroidal magnetic ring to actuate the clutch position hall sensor, any metallic residue from the brake/clutch reservoir will become attached to and held by this.

 

The problem with the intermittent sticking clutch pedal which will soon develop to failure requiring more and more frequent bleeding is air drawn into the system through the O ring joining the two plastic parts of the concentric slave cylinder without leaking any fluid.

 

Fair enough re no metal parts (my Fiat does have metal parts!)  but the fluid that came out of mine , which was an external slave (petrol Superb 1.4tsi)  , was a very murky dark colour. Mine was fine after fluid change although to be honest a few months later the whole clutch was changed anyway so a new slave was fitted whilst it was in bits. 

 

Slave cylinder is failing. 

3 hours ago, bigjohn said:

 

Fair enough re no metal parts (my Fiat does have metal parts!)  but the fluid that came out of mine , which was an external slave (petrol Superb 1.4tsi)  , was a very murky dark colour. Mine was fine after fluid change although to be honest a few months later the whole clutch was changed anyway so a new slave was fitted whilst it was in bits. 

 

 

My fluid was also a horrible colour and there was schmoo all around the toroidal magnet, replacing the master cylinder and flushing/bleeding made no difference to losing the clutch frequently neither did replacing or removing the innards of the peak torque limiter, fault is always air drawn in via the O ring joint between the concentric slave cylinder and the pipe that leads out through the bellhousing. Air rises and lodges in the void designed for that purpose in the T branch under the bleed thumbscrew, very easy to bleed but wont last long.

The fluid was replaced I believe 5 years ago, but it doesn't specifically state they bled the clutch through.

 

I'll exchange the fluid and give the clutch a bleed through - at this point I've not had to do anything other than wait a second to let the pedal return. I've also had a look at the clutch pedal pivots on the parts diagram and will go and lubricate everything that needs it. 

 

The car has 85k miles on it, and it really hasn't wanted for anything major (except the crank seal during the cambelt replacement), so I can't get too mad at it!

 

Cheers guys!

If it returns but slowly it could be a partial blockage in the return restrictor of the bleed block AKA clutch peak torque limiter but I would expect that to be constant, bleeding may not expel the particle but replacement is very cheap and easy, removing the guts even cheaper and then you get a car that does what you command it to do via the controls rather than its own thing.

 

With the daft thing operational (mine currently is) I dare not make a quick exit across a junction using anything but a light throttle for fear of unpredicatbla end uncontrollable clutch slip.

 

Spray grease to the clutch pedal control loading cam actuator will aid the pedal return and also give you some assistance on the way down, it works after about 60% travel in both directions.

 

Anything like that is worth a try in the hope of avoiding what might be the inevitable gearbox out job.

Edited 4 August, 20241 yr by J.R.

This will probably be a master or slave cylinder failing internally.  Unless you've had a catastrophic failure of the release thrust baring, it is unlikely to be a gearbox out job.  However, if it is, then please replace the clutch and release baring whilst you are there!

The master cylinder cannot cause the problem.

 

It will 100% be a gearbox out job to replace a concentric slave cylinder fitted to all of the 6 speed gearboxes (to my knowledge, happy to learn otherwise) and many of the 5 speed boxes, the slave cylinder does not fail due to the release bearing breaking up, it does not actually fail at all and will work just fine when the air is bled out of the system however the air is drawn in via the O ring joing between the casing extension and the feed pipe of the cylinder, movement through vibration and lack of restraint wear the O ring such that it will seal under pressure but draw in air under a partial vacuum, the exact condition created when someone lifts up the stuck clutch pedal.

On 03/08/2024 at 23:11, J.R. said:

 

Its known as the clutch peak torque limiter, in operation it slows down the speed at which the clutch is released, if you change gear too quickly or sidestep the clutch to spin the wheels the clutch will slip protecting the transmission, it has no metallic parts and cannot rust.

 

The master cylinder has no metallic parts either, it has a plastic piston in a plastic bore, even the pushrod is plastic, there is a sintered toroidal magnetic ring to actuate the clutch position hall sensor, any metallic residue from the brake/clutch reservoir will become attached to and held by this.

 

The problem with the intermittent sticking clutch pedal which will soon develop to failure requiring more and more frequent bleeding is air drawn into the system through the O ring joining the two plastic parts of the concentric slave cylinder without leaking any fluid.

 

Interestingly enough, I always seem to notice it when pulling out of, or coming up to junctions. For instance, on my way home there is a long straight 30mph with a sudden, very steep descent onto a roundabout, resulting in braking and requiring a change down to 2nd (this is where it first did it, and I thought I had caught the edge of my right shoe on the clutch). The last time it did it, a week ago, was about 30 seconds from startup pulling out of a junction (not harshly), where it must have stopped just shy of top then came up and tapped my foot (although it didn't clunk or anything, like the clutch was fully engaged). Yet there is plenty of traffic light junctions up to that point where I will mix sitting with clutch in, and sitting with clutch out in neutral, and never seem to have an issue.

 

I've had a quick look at the pedal box, clutch seems to be free to move, mats are in the right position in the clips and not fouling, and there isn't any free play in the clutch pedal like it's twisting or moved and getting caught, and moving it by hand I couldn't feel it being notchy or getting caught. I also had the brake fluid bled today, unsure if they did the clutch too (I forgot to ask), but as I'm almost certain the air box has to be taken off I doubt they have for what they charged me (I deep down didn't want them to do it in case the vacuum bleeder caused more issues!).

 

There is a little part of me that is thinking I'm making this up though the rarity of it happening 😄

On 04/08/2024 at 18:14, J.R. said:

Spray grease to the clutch pedal control loading cam actuator will aid the pedal return and also give you some assistance on the way down, it works after about 60% travel in both directions.

 

I will add this to the list of jobs, first off finding where it is 😁

So, it finally did it, it stuck (>50%) down and stayed there. Three times. All three times was when I came to finish my journey, stopped, clutch pushed down, and turned off the engine with clutch down.  No idea if that's anything to do with it. Had to nudge it with my toe and it popped back up (I did not have to pull it all the way up).

 

I have still to actually identify this cam actuator bit, but I'll be honest I'm struggling to get under the plastics, I might have to take some of them off. 10 years ago I bet I could have snaked my way into seeing it but my back really isn't up to it now ! 🙃

 

Also to note, it also stuck down a couple of times then popped back up whilst driving but the clutch was definitely engaged (enough to boot it from a set of lights, yes I know it's only 110hp :D).

What a bottom ache! Went to drive today, touched the clutch pedal and it shot to the floor by itself. Pull it back up, it'll shoot itself back to the floor again if you even breathe on it slightly too much.

 

At least it's at home, I suppose it could be worse 😞 It's been absolutely fine for the past 4 months!

Edited 13 January, 20251 yr by micro

On 13/01/2025 at 14:16, micro said:

What a bottom ache! Went to drive today, touched the clutch pedal and it shot to the floor by itself. Pull it back up, it'll shoot itself back to the floor again if you even breathe on it slightly too much.

 

At least it's at home, I suppose it could be worse 😞 It's been absolutely fine for the past 4 months!

Did you ever nail the issue down? I have the same problem but its been happening for while now.

On 06/08/2024 at 10:40, J.R. said:

The master cylinder cannot cause the problem.

 

It will 100% be a gearbox out job to replace a concentric slave cylinder fitted to all of the 6 speed gearboxes (to my knowledge, happy to learn otherwise) and many of the 5 speed boxes, the slave cylinder does not fail due to the release bearing breaking up, it does not actually fail at all and will work just fine when the air is bled out of the system however the air is drawn in via the O ring joing between the casing extension and the feed pipe of the cylinder, movement through vibration and lack of restraint wear the O ring such that it will seal under pressure but draw in air under a partial vacuum, the exact condition created when someone lifts up the stuck clutch pedal.

Hey JR.

What would you recommend to fix the issue without a clutch replacement? My clutch is in great condition as its not that old, and still grips on full clutch drop perfectly and I've got an Octavia VRS estate diesel, so its heavy.

My pedal just seems to get "stuck" on the return (when lifting my foot). Gently touching the underside of the pedal will return it fully. This only happens in slow traffic around town, motorway driving it works fine.

Thanks in advance.