Hi all,

 

i'm new to the Forum so hello to all and hoping to be able to pick up useful tips and guidance from the more experiance and mechanically savy!! 

 

We recently purchased our forth Skoda from a main dealer, it is a 2013 Fabia with 50k on the clock with a 12 month warranty. 

 

All was well for the first week and then the clutch started sticking half way down when changing gear, this was intermittant and not everytime it was driven. I contacted the dealer 15 days after we picked it up after the Mrs was driving it, luckily  outside our house (cul-de-sac) and the clutch pedal stuck completely down whilst she was changing gear. She had to turn the engine off, reach down and pull the pedal back up as she couldnt engage a gear. 

 

We called Skoda assist and the AA guy who came out said that there was no sign of any fluid leaking and that they would take it back to the dealer for us to be looked at but not to expect too much as they would probable not want to spend too much on it under warranty and may just try and fob us off.

 

They took it in and after a day or so contacted to say they could not replicate the fault and had re-bleed the system to cancel out any air being in the system. 

 

Any ideas on what people think it could be? I have contacted them to ask if they checked the Master and Slave cylinder and am awaiting a response. 

 

Not really happy if there is likely to be a big repair bill at some point soon and would rather get our money back but they are refusing stating there is no fault.

 

Steve

 

 

 

A very widespread problem but one that the dealerships are in complete denial of.

 

You can read from the above what they need to do but you have zero chance of convincing them, they play parts bingo with the customers money but wont when its them that have to pay the bill.

 

I bet it started on the first warm day didn't it!

 

If you contact the previous owner they will probably tell you that was the reason they traded it in.

AA guy who came out said not to expect too much as they would probable not want to spend too much on it under warranty and may just try and fob us off.

 

He has seen it all before!

Thanks for the response, i have had a response from them stating that i jsut need to have it back and hope all is ok!! 

 

They have already told me that the warranty will only cover faulty parts and as they cannot diagnose an issue they cannot do anything under warranty!! 

 

Given how recently we puchased it i have advised them of my intention to use the Consumer Rights Act 2015 , now they have had an attempt at fixing it, if it happens again which it sounds like it will, i will be requesting a full refund. 

 

I suppose i just need to use it alot for the next few days to replicate the issue and i can then fingers crossed take it back to them proving the fault and they will not be able to deny it has one!! 

 

Steve

If they bled the system they may have removed or dislodged the particle that will have been obstructing the fluid return through the clutch torque limiter so the problem may take a long time to re-occur, the damage will have been done to the master cylinder though by the natural instinct of lifting the pedal back up.

 

Not sure how long you have left to refuse the vehicle but the hot weather will be the time that the fault will re-occur if it is going to.

Contacted the MD of the dealership and he is coming back to me tomorrow so watch this space!! 
 

thanks so much for taking the time to give me your advice, really appreciated 

Having spent an evening stripping and modifying a pair of clutch master cylinders I am now 100% certain of what the problem is and how to overcome it.

 

It is 100% definitely due to the plastic master cylinder pushrod pulling out of the piston and then becoming a sliding fit in its location, unless the two are firmly locked together the piston will not return properly and new fluid will not be drawn into the system when required.

 

It will first occur when the cylinder is heated from the DPF, its more apparent on the higher powered engines, and will be aggravated by the piston returning slowly due to the clutch torque limiter, the heavy pedal return spring will pull the pushrod partially out of the piston, from that point on the problem will be progressively get worse.

 

If the pedal fails to return the first thing to do is clean and open up the bore of the clutch torque limiter, do not pull the pedal up you will make things worse.

 

If the problem persists you need to then replace the master cylinder but you must modify it before fitting, you will probably find that the pushrod can easily be pulled from the piston by hand, the retaining collet has to be glued in with a strong adhesive, I am using PU gel construction adhesive, a trial with Loctite was not successfull.

 

Getting the cylinder apart needs a magician and its taken me a month to finally find how to do so, there is a plastic bush that needs a dozen internal spring loaded lugs compressing, it can be done with a 2.5mm or smaller tywrap or lockwire, I doubt that a VAG dealer will have ever done so.

 

Thats a very simplistic explanation and the real problem is that it has to be assembled blind, too much glue will mean the collet does not seat properly & its scrap or will gum up the works.

 

To test if a cylinder is working and fit for service you must pull hard on the pushrod and it should not detach, with it fully withdrawn you should be able to blow through the reservoir fill port and there be no restriction.

 

I have had 2 new cylinders (aftermarket) fail when I tested them by hand and the expensive VAG cylinder failed under high temperature operation, when I remove it I expect to find that like the aftermarket cylinders the pushrod collet is not mechanically retained.

 

If VAG had simply fitted an internal return spring like any other master cylinder has this problem would never have occurred, old school Girling cylinders dont have the pushrod connected to the piston, its an open ball and socket, if a vehicle is laid up & the piston rusts & does not return fully you get the same problem.

The reason that the pedal may go half way to the floor first thing in the morning is that when the engine cools & the system would want to draw fluid from the reservoir the piston is not far enough back to allow the flow so the partial vacuum instead pulls the piston further down the bore.

This sounds a lot like it has been caused by "progress/evolution" and unfortunately that can mean "good/better due to much cheapness".

 

Any idea who is the manufacturer that VW Group have sourced that hydraulic cylinder from, I'd guess it is that OEM supplier's design that has changed and is causing this as VW Group will normally just be buying what is available ie a "hydraulic clutch control mechanism".

 

Years ago, I read about something similar happening with the clutch on B8 Audi S4 with 6MT and there was a (performance related) company in USA that bought in new master and slave cylinders and replaced lots of the plastic innards with alloy parts to address a few issues including this - the Audi S4 and similar powered Golfs etc also have these "delay/damping" fluid return restrictors which it seems lots of people just love to get rid of, for me, so far so good.

When it happens just take a picture or short video with your phone so you can show it to dealer.

37 minutes ago, rum4mo said:

Any idea who is the manufacturer that VW Group have sourced that hydraulic cylinder from, I'd guess it is that OEM supplier's design that has changed and is causing this as VW Group will normally just be buying what is available ie a "hydraulic clutch control mechanism".

 

Things have changed a bit since the 70's when every vehicle would have had one of very few standardised Lockheed master cylinders under the bonnet with critically the Lockheed (or other OEM) part number on.

 

The specification will be a VAG one and the assembly lines will be supplied by OEM's like Luk, Valeo etc.

 

No way could they change the design without the full collaboration of the vehicle manufacturer, its usually the latter driving the change through the constant quest to reduce costs.

Humm, I'm old enough to remember when Ford and possibly other car makers, tended to fit quite a few sort of similar master cylinders to the braking system, the only way to get the correct size of seals was to read off the info on the plastic tag fitted to each master cylinder!

My car had this problem, when it was off at the mechanics being sorted for the NCT I mentioned it and he figured out that the brake fluid had gotten low enough to let a little bit of air into the clutch line and cause it to stick. He bled the system and no more problems. Weirdly it only happened when my mother drove it, never when anyone else including me was driving. Seatbelts get very stiff when she's in it too...

That could not have happened, the brake fluid warning light would come on before the take off to the clutch cylinder sucked air, also the clutch slave cylinder is at least 6" lower then the fluid reservoir, even if the level sensor did not work you would have to have a leak in the clutch system.

 

In any case air in a hydraulic line or the master cylinder will not prevent the pedal from returning under its spring pressure, the spring acts on a cam with detents at the top & bottom position, only 2 conditions would prevent the clutch pressure plate from pushing the release bearing back displacing the fluid & hence the pedal back to the top detent position, fluid return flow being blocked (debris in the torque limiter bore restriction or a burst slave cylinder seal or hydraulic line.

28 minutes ago, J.R. said:

That could not have happened, the brake fluid warning light would come on before the take off to the clutch cylinder sucked air, also the clutch slave cylinder is at least 6" lower then the fluid reservoir, even if the level sensor did not work you would have to have a leak in the clutch system.

 

In any case air in a hydraulic line or the master cylinder will not prevent the pedal from returning under its spring pressure, the spring acts on a cam with detents at the top & bottom position, only 2 conditions would prevent the clutch pressure plate from pushing the release bearing back displacing the fluid & hence the pedal back to the top detent position, fluid return flow being blocked (debris in the torque limiter bore restriction or a burst slave cylinder seal or hydraulic line.

Huh, i'm just saying what I was told. Not had a problem since so he must have put something right.

I would believe what a mechanic told me over what a service receptionist said but that aint saying much

On 18/04/2021 at 23:03, DieselMonte said:

 Weirdly it only happened when my mother drove it, never when anyone else including me was driving. Seatbelts get very stiff when she's in it too...

 

Is she a very nervous jerky driver by any chance?

Hi all, just a little update, managed to get a full refund on the car and so now on the look out for another!! 

 

Does anyone know if this is a problem with the tranmission/clutch on particular models or years? Looking for another Fabia but want to try and avoid this issue occuring again if possible

 

Thanks in advance 

 

Steve 

No, the issue is rare and unrelated to the make and model.

I am still suffering and its looking like the root cause of my problem may be other than the defaults that I have already rectified.

 

It seems to be set off by high revs rather than temperature, my engine will rev much higher after the remap than before although I never use it, I gave it one acceleration run through 3rd & 4th gear hitting peak revs & am back with the intermittent jelly clutch pedal. I think that the pressure plate is causing fore and aft oscillation of the release bearing at high revs and pushing fluid back, the modified bleed block could be making it worse.

 

When the wind drops the original unmodified one will be going back on, this is the second maybe 3rd time as much as I relish a challenge and enjoy getting to the bottom of a problem this is beginning to wear me down, I need to have confidence in the vehicle for it will soon (I hope) be used for towing a heavy laden trailer for several cross channel house removal journeys.

 

I might have to bite the bullet and remove the transmission & replace the clutch & DMF, something I dont want to do unless I am sure they are faulty.

 

Crankshaft end float could also be an explanation, unlikely I think on a VAG engine but I need a helper to rule it out.

Well things got progressively worse so the bullet had to be bitten, there was only one suspect left, the concentric slave cylinder so it was off with the very heavy 68kg transmission unit and a DMF clutch & slave cylinder change.

 

Having ordered a new old stock cylinder from Ebay France and comparing it to the latest revision one that came with the clutch/DMF kit I was fairly sure what the problem would be even before tackling the job, the old one was a one piece aluminium casting, the new one was plastic and moulded in two pieces with an O ring sealed joint hidden within the bellhousing.

 

The connection stub sticking out of the bellhousing could be wobbled around and it turned out to be the joint rotating, the joint on the new part was solid, sure enough the O ring had a flat on one side and had wear marks, it was allowing air to be drawn in despite the head of fluid above it but had not leaked even one single drip, that part remains a mystery.

 

The thrust bearing was faced with plastic where it contacted the pressure plate fingers and had indentations, I dont think this damage was relevant to the problem but both my new release bearings had metal contact faces.

 

The DMF had slight wear and the lateral oscillation may have contributed to the indentations on the release bearing or vibrated the fluid joint allowing air ingress, it was silent at low revs as is the new one but at high revs its much quieter, now its a diesel sound rather than a high rev death rattle.

 

I decided to fit the aluminium cylinder so as not to risk a future problem with a 1ct O ring requiring transmission removal, I think my car may have been originally fitted with an alu cased bearing & that the clutch has already been replaced, some bolts were loose, the starter solenoid connector broken and other indications that the job had already been done by an inexperienced or slapdash mechanic.

 

Also someone had abused the clutch, pressure plate & flywheel had burn marks, the pressure plate was dished, 1.5mm over a 40mm wide contact face and the drive plate worn thin on the outside only.

 

The clutch and its hydraulics are behaving perfectly since replacement, also the gear selection is much improved as the counterbalanced quadrant that the cables attach to was loose on the selector shaft spindle (more signs of being worked on), so loose that the spline would soon have stripped and I would have lost all gears

 

 

 

 

 

 

Edited 21 June, 20214 yr by J.R.