Driving around this evening noticed that the clutch pedal was well down with only about 50% of normal travel, seemed to be working OK though.

I hooked my foot under the pedal and pulled it up to where is should be and somewhat surprisingly it stayed there and is now working perfectly normally.

Thoughts?

Concentric slave cylinder drawing in air through the O ring joint between the two plastic mouldings that make up the assembly.

 

You are probably going to be sent on a parts bingo merry go round of changing the master cylinder, repeated return visits for bleeding, replacement of any other external parts like the flexible hose or bleed block and eventually a full clutch replacement, just make absolutely sure they do replace the slave cylinder instead of looking at it, deciding it isn't leaking (which it wont be) and leaving the old one but charging you for a phantom new one as happened to another contributor recently who is about to pay for the whole job to be done a second time.

BTW, you might think that it is working perfectly normally but it ain't, the problem will recur very quickly and get worse.

 

Lifting the pedal up manually is actually the worse thing that you can do but unless you get out and bleed the system straight away you have no other choice but to draw more air in by doing so.

∆∆∆∆∆ Wot he said ∆∆∆∆∆

My slave is external with a bleed nipple, this is a 1.2 CBZB engine.

 

Not showing any loss of fluid in the master cylinder.

 

Never a good time but this couldn't happen at a worse one as my wife is in hospital having busted her hip and I'm back and forth to the hospital 2-3 times daily.

 

Two screws to remove to pull that cylinder out a little and see if there's any sign of leakage at the business end. 

If the problem hasn't happened again since the 'foot hook' I'd be inclined not to investigate further until it does though.

Thanks.

 

Only driven a few miles since it happened but will be out again today.

 

Given that the foot hook worked I'm now more inclined to see the problem as the master not the slave, can't see how that would have any effect on the slave.

 

As I said no apparent loss of fluid.

 

Having now had a good look neither cylinder is much of a job to replace so that's a relief.

 

For what it cost's I might just replace the master anyway - maybe even both - a couple of hours in my garage is infinitely preferable to the ignominy and inconvenience

of a total failure on the road!

 

Driven about 30 miles today and the clutch has behaved perfectly normally.

 

Definitely odd 

It's got weirder.

 

Driven not far short of 200 miles now with no problems, came out of the hospital about an hour ago, stuck it in reverse and nothing, car didn't move.

 

Clutch felt perfectly normal pressure wise but with my foot OFF the pedal completely I could cycle through all the gears as if it the pedal were fully depressed or the engine not in fact running.

 

Switched off and restarted and suddenly it's working again, has got to be sticking master cylinder but strange that apart from that initial 'foot hook' incident the pedal has never felt anything but normal.

This sort of thing can end up being costly, as is it the master, or the slave.

Most of the time it ends up as guess work.

I would at this stage, remove the master & thoroughly look at it, even removing the boot that covers the push rod hole, & check there. (also for any leaks)

Also check the clevis pin for wear, that's if this model has one.

Remove the push rod with the piston that carriers the seals, check seals & the internal bore of the cylinder.

If the bore shows any sign of wear, then replace the cylinder, which to me is the problem..

Good luck.

 

Ps. Have a look at this........

 

Edited 28 March, 20224 yr by Carlodiesel

I'm afraid that none of the above is appropriate.

 

No boot to remove.

 

No clevis pin.

 

If you manage to remove the plastic pushrod from the piston you will break the retainer, these barely retain the pushrod in the piston against the force of the control loading spring as it is and is another reason why you should never lift the pedal manually as it is likely to dislodge, even just testing the action of a new cylinder by hand and pulling the pushrod back (there is no internal return spring) can dislodge it and stop the retention, I broke a new cylinder before even fitting it.

 

The piston does not carry the seals, the seal, or any seals, the cylinder has but one O ring in a retaining groove in the outer bore like a brake caliper piston.

 

The cylinder is clipped together in the factory and will only come apart for a man on a mission willing to make his own special tooling (me!)

 

The bore can be as worn as it cares to be as it does not form a seal, the fluid is deplaced (displaced, sorry for the Franglais) by the volume of the piston intruding into the cylinder, fluid is intended to pass between the piston & bore to lubricate it, it will not be worn in any case assuming that anybody is as stubborn as me to get the thing apart to see.

 

Whatever you do do not follow the misguided advice on the video, luckily he had a system full of air, otherwise he would either have broken the plastic pushrod even by hand pressure or detached it from the piston by lifting it up as he did.

 

Don't ask me how I know both these things or how many new master cylinders I got through trying to avoid biting the bullet

 

A question for the OP, when your clutch did not take up the drive & remained disengaged did the pedal rise up on its own?

 

As you have found how easy it is to remove the airbox for the photo I suggest you bleed the clutch, it is dead simple due to the unorthodox master cylinder, no pumping, pressuring and no tools needed, simply put 6" of clear hose on the nipple standing vertically, open the bleed valve 180° using your fingers (assuming its a plastic knurled knob like mine, if not use a spanner) watch a stream of micro-bubbles come out with the fluid, it will stabilise after about 2 or 3" and just wait till no more air comes out then close the nipple, so little fluid is lost that you dont really need to top up.

 

If air comes out it will at least buy you some time and indicate that the problem is the slave cylinder, it probably wont be leaking but will instead be drawing in air, if all good at that end then change the master cylinder, a tricky job the first time but gets easier after many repetitions which should not be advised!!!!!

 

You are dead lucky to have an external slave cylinder!!!!

Edited 28 March, 20224 yr by J.R.

Yes, apart as I said from that one initial 'foot hook'- and even then the pedal has risen up on it's own albeit only to about a half way position - it has always felt normal.

 

I did not need to remove anything for my photo of the slave.

 

Already got a new master, €45 from Amazon, just got to find the time to fit it!

 

Interesting video but I know for certain that there is nothing wrong with the clutch itself and my slave is external and at around the same price as the master so not a wallet busting job, back busting is something else!

 

Why do they need to make something as basic and simple as a clutch master cylinder so complicated.

 

I could happily do without the clutch depression to start too!

On the contrary, they have made it remarkably uncomplicated, one piston, one seal, all plastic including perhaps the piston now I come to think of it.

 

I also totally hate having to depress the clutch to allow the starter motor to operate, especially when I am working on the engine in oily overalls.

 

My master cylinders were £110 for the first one from TPS (needed urgently) and €18 each for the subsequent ones.

 

Try the bleeding, it may save you from the difficult (first time) master cylinder replacement.

 

Good luck, don't know why I am saying that as you are already blessed with it!!!!!!!!!!

Edited 28 March, 20224 yr by J.R.

300 miles or so now and clutch still behaving itself, did flush it through with fresh genuine VW fluid this morning though. I'd bought 1lt with the intention of flushing the brakes through at 110,000km which is when I plan to next change the engine oil.

 

Have to say what came out looked as clean and pristine as what went in.

 

Were the original master cylinders all plastic?

Ha, clutch has been performing flawlessly - until this morning when it stuck down at the first start of the day. It's now approx. 1500km since the last instance.

 

Torn between living with it and replacing the master which I already have, it  doesn't look that much of a task and know I should do it but I've become a bit of a lazy bas*ard not to mention that presently it's in the mid 30's here so if it's to be done it will have to be an early morning job.

 

Ironically per my last post I also did my 110,000km oil change today.

 

As an aside I must say that compared to my previous MK1 Octy, which was a PITA, at least until I cut a square out of the under body shield by the sump plug, on the Yeti it's a pleasure as the drain plug is completely accessible without having to removing a damn thing and the the dual drain filter makes it a mess free 15 minute job!

 

 

34 minutes ago, KiNeL said:

As an aside I must say that compared to my previous MK1 Octy, which was a PITA, at least until I cut a square out of the under body shield by the sump plug, on the Yeti it's a pleasure as the drain plug is completely accessible without having to removing a damn thing and the the dual drain filter makes it a mess free 15 minute job!

With a £12 Lidl oil vacuum pump no need to even go underneath and no drain pan to clean up.
Used it for the last 3 years and no way am I going back under any more.

Each to their own 

 

Having just found this video now wondering if the problem is anything to do with the actual MC at all!

 

Skip to 2 mins for the salient moment.

 

 

Edited 18 May, 20224 yr by KiNeL

Can you explain what the salient moment was, I ran out of patience and the music was annoying the hell out of me.

22 minutes ago, J.R. said:

Can you explain what the salient moment was, I ran out of patience and the music was annoying the hell out of me.

It's only about 7½ minutes with no voice so just mute the volume.

Exactly!

Oh well I will just have to live in ignorance of what the salient moment was then.

 

If it really was a "moment" then why not share what it was rather than making someone spend 7.5 minutes of the precious little time left for them on this planet?

 

There sure wasn't anything salient I could see at on or around the 2 minute mark.

11 hours ago, J.R. said:

Oh well I will just have to live in ignorance of what the salient moment was then.

 

If it really was a "moment" then why not share what it was rather than making someone spend 7.5 minutes of the precious little time left for them on this planet?

 

There sure wasn't anything salient I could see at on or around the 2 minute mark.

..I watched it all 3 times and still couldn't make out any salient moments??....so I would appreciate an explanation as well??

19 hours ago, J.R. said:

Can you explain what the salient moment was, I ran out of patience and the music was annoying the hell out of me.

You can simply drag the progress bar to the 2 minute mark to see the "salient moment" without having to watch the video from the start

For those who can't (or won't) get it, at 2 mins what the guy is effectively doing is pulling a stuck down pedal up from the floor when it snaps into the 'up' position - why, because it's being held in the locked down position by the helper spring being in an over centre attitude.

 

Clear now?

 

 

So bit the bullet today and decided to replace the MC.

 

Based on the instructions from the manual (see attached) it didn't appear that daunting of a task but typically it didn't go to plan.

 

I'd fabricated a T10005 tool from a welding clamp which performed the task reasonably well but also took the precaution of acquiring a replacement for the clip, more on that below.

 

Getting the old cylinder out went well enough but trying to fit the new one with the new clip I just couldn't get it to click in  place, then it happened, the helper spring popped out, why I have no idea but hey I thought, no big problem I'll drop the pedal out and refit it - but oh no, for some unfathomable reason the bolt which holds it in is inserted from the steering column side meaning that there was no possible way to get it out without either removing the entire column or taking the complete pedal assembly off the car. What they were thinking I can't imagine as there is no need whatsoever for it to be fitted from that side, it's a simple 8mm bolt acting as a pivot and can go either way and from the opposite side it would have come out without issue. 

 

No way was I going to remove the steering column and after considering - but dismissing - the angle grinder option I set to removing the pedal assembly. The video I posted earlier came in handy as it gave me a clue for removing the top nut which I could barely see but did mange to remove using three long 1/4" extensions through the gap under the steering wheel all the time wondering how I was going to refit it as I do not have a 1/4" 'wobble' extension. Once the assembly was out I cut away come of the sound deadening padding which was partly obscuring it which at least gave me an improved view of where I would be working when refitting it.

 

On the bench I examined, compared, and measured the new clip against the original and discovered that not only was the new one about 1mm longer between the arrows but also that the slot in the end was narrower so there was no way it was ever going to fit so I chucked it aside and reused the original. 

 

I reassembled it all on the bench as per the video and refitted to the car, the top nut was a b*itch as anticipated but I eventually got it back on.

 

I bled the system and quickly got a good pedal but then noticed a weep from the pipe where it fits in the MC so removed it again, checked and refitted the rubber seal, after which is sealed correctly, as a check going forward I put a piece of black duct tape on the chassis member immediately below the connector which should immediately reveal any drips.

 

As stupidly expensive as they are I may invest in a new seal just in case.

 

What should have been a max 1.5 hour job turned into a half day marathon and being of 'an age' Instructions.docwith all the contortions in the footwell I expect to be totally seized up on the morrow!