Sticking Clutch Pedal After New Clutch - Advice Please

[ColinR]

I am seeking a bit of knowledge to help me have a sensible conversation with the OPC that did the work.

My 996.2 GT3 went in to Porsche for a clutch renewal - that included all parts being replaced i.e. flywheel, release bearing, clute plate, presssure plate, release fork etc. Before the work, the clutch was working but was getting heavier and after about 20 yrs, I felt a full refresh was due.

The car has been returned. The clutch engages and disengages, the pedal is lighter but does not release correctly; it sticks after the clutch is disengaged (ie the gear is changed) and remains stuck for a few seconds (with the foot off the pedal) and then springs back (with some force) to the resting position.

It seems to me that something is fouling the mechansm which is finally overcome by the clutch pressure plate or return spring?

Has anyone any thoughts about what the issue could be and the fix? I will be speaking to the dealer on Tuesday so any help before hand would be much appreciated.

many thanks

 

[Senoj]

Well it's by no means normal.

Surely they tested it?

My advice is get them to come and get it. I had a horror story with an OPC clutch change, never again.

 

[NXI20]

As Senoj says, that's not normal.

I'd guess the clutch release fork isn't fully engaged in its bush or is exessively worn. Was the fork changed? They are made of chocolate these days & can wear out before the clutch in some cases.

 

[ColinR]

At the moment I am remaining positive about the OPC response.

I replaced everything - I hoped I would avoid the old chestnut of "it does not work because of the old bits you did not change". So I did replace the fork and even all the bolts and bushes.

Thanks for your thoughts

 

[deMort]

I would ask the question ... was the gearbox shaft tube replaced ?

The release bearing slides on this part .. it's possible its sticking ..

After that .. the clutch is new .. as it releases it pushes against the slave cylinder which in turn forces fluid back into the master cylinder which relieves pressure and the booster spring assists in raising the pedal ..

The clutch pedal booster spring might need replacement ... new clutch .. less force perhaps .

 

[ColinR]

Thanks deMort for your thoughts.

The operating shaft and guide tude were both replaced but not the clutch power spring onto the pedal. So definately worth looking into. The pedal does pop back with some force - once it decides to come back up.

I am now also wondering if the whole system was not properely aligned when put back together - is that even possible? Meaning that the moving parts are not moving freely, tighter tolerances requiring great precision when re-assembling?

Such a frustration as the weekend has been perfect driving weather.

 

[Alex]

They've not bled it properly - guaranteed. I had the exact same problem at my last clutch change.

 

[deMort]

I am now also wondering if the whole system was not properly aligned when put back together - is that even possible? Meaning that the moving parts are not moving freely, tighter tolerances requiring great precision when re-assembling?

If the slave cylinder was replaced then air in the system is possible .. if it wasn't then its the same now as when it went in for work ..

Alex,s point is very valid though .. it takes only a tiny amount of air to make a big difference in a hydraulic system .

You can't assemble clutch incorrectly .. we use tools to line up the friction plate to the cover plate .. if not aligned then you simply can't get the gearbox to go back on .

Have they made a mistake ? hmm .. i'm struggling to say yes to that as i can't think of anything off hand ..

The original clutch was very heavy .. this is basically the cover plate " fingers " being stiff " .. rather common on older clutches across some of the models ..

This basically will force the fluid back into the master cylinder with greater pressure imho .

New clutch .. less pressure and i'm looking for an item or items that may now be causing this .. slave cyl and no i can't see it ..

I can however see it being the master cyl or the clutch booster spring .. for me i would start with the booster spring ..

Obviously i can't see the car and it might be more obvious in person but the above is what i think .

 

[ColinR]

Once again, many thanks to everyone for their thoughts and advice - just shows how supportive the Porsche world is.

I feel much better equiped for my conversation with the OPC tomorrow. I am reassured that it cannot have been put back out of alignment and most likely something amiss with the helper spring, master cylinder or air in the system.

I will update here once everything is settled incase anyone else has a similar problem in the future. My dealings with the OPC have always been positive so I am hoping for a good outcome.

 

[Alex]

They'll know straight away they've not bled the clutch fully. Rebleed and all will be resolved.

 

[Diggermeister]

I have no nuggets of wisdom to dispense here.

Just to say:

1. Hope OP is able to resolve this with OPC and look forward to knowing the results.
2. As usual, absolutely outstanding response from the 911uk forum.

I read a lot of these how to/what's wrong? type thread, without comment, just for the technical interest. So thanks. :thumbs:

 

[Slippydiff]

A few others :

Clutch plate fitted back to front.

Master cylinder seal failing.

Slave cylinder seal failing.

System needs re-bleeding.

Clutch fork crosshaft bearings semi-seized (they're needle rollers (not bushes) and the grease in them dries out)

https://www.design911.co.uk/fu/prod...earing-Porsche-911---964---993---996---997_2/

Good luck getting it sorted, and keep us posted.

 

[ColinR]

Hi,

Just back from a visit to the OPC so I have an update.

The system was found to have air in it. Its been bled and the pedal operates normally. So quite happy that this is resolved but will keep an eye on it.

Many thanks for everyone's support and advice. It was really helpful and prepared my for my conversation with the dealership.

The clutch is loads lighter - 50% lighter (if I was to put a number on it). So really happy with that as the clutch had got heavier over the years even though it did not slip.

The dealership were not particulary apologetic and I did not make a fuss as I know they have been up against it with staff off with covid.

So another new experience with the car and should it happen again, I will know whats what.

 

[1marc]

Great resolution. And re the apology, it's a case of picking your battles, so I'd have been inclined to do the same in this scenario. You can just enjoy the car now. 👍

 

[deMort]

They'll know straight away they've not bled the clutch fully. Rebleed and all will be resolved.

Spot On :thumb:


OP .. sorted which is good .