Clutch pedal dropped to the floor - Help

[RUM4MO]

Yup!

 

[Jay5959]

Problem is the master cylinder

I can obtain the master cylinder alone for about £60 from another parts supplier. OEM of course.

Butt then TPS do the master cylinder only with the clutch pedal assembly for about £150+

Question is, is it recommended to replace both together, or just the master cylinder alone?

I would probably change the pedal assembly too for peace of mind. Happy days that it’s not the slave cylinder that failed

 

[BillyCool]

Both statements I can agree with

TPS did mention the part has been modified

So perhaps a fault was identified and its now been resolved.

Is that similar to the:

• `modified` heater matrix
• `modified` water pump
• `modified` thermostat housing
• 'modified` expansion tank

VAG seem to spend a lot of time `improving` things to only `modify` them when they realise they don't work very well.

 

[Yern]

Is that similar to the:

• `modified` heater matrix
• `modified` water pump
• `modified` thermostat housing
• 'modified` expansion tank

VAG seem to spend a lot of time `improving` things to only `modify` them when they realise they don't work very well.

Release it to the masses...doesn't work well so modify it...Bill Gates made billions this way

 

[TGH119]

Hi,

Having similar issues with my Leon 2015 2.0TDI, are you sure the Slave cylinder is a box out job?

Looking at the workshop manuals it looks as though it's external with a couple bolts and hydraulic line.

Started having issues a few months ago and had the Master replaced which seemed to fix but the past few weeks have been experiencing the same issues so was going to look at replacing the slave cylinder if anyone has any other ideas?

 

[garybuttle]

Hi,

Having similar issues with my Leon 2015 2.0TDI, are you sure the Slave cylinder is a box out job?

Looking at the workshop manuals it looks as though it's external with a couple bolts and hydraulic line.

Started having issues a few months ago and had the Master replaced which seemed to fix but the past few weeks have been experiencing the same issues so was going to look at replacing the slave cylinder if anyone has any other ideas?

I have a 14 plate 150 TDI and yes the slave cylinder is in the gearbox made from 100 % real plastic and the back blew out of it at around 70 k miles and guess what , the new part has been modified

 

[TGH119]

I have a 14 plate 150 TDI and yes the slave cylinder is in the gearbox made from 100 % real plastic and the back blew out of it at around 70 k miles and guess what , the new part has been modified

Apologies, after doing more digging I believe I have identified the correct gearbox and it would appear I was looking at the incorrect one! Oops!!

I've done just over 80k in mine and it would seem this is a common problem. Do you know a rough estimate for the cost of replacement slave cylinder?

 

[garybuttle]

Hi cannot remember exactly but you may as well do the clutch whilst the gearbox is out. Got mine from euro carparts the original luk ones which are standard equipment. Did get a new DM flywheel as well but returned it as old one was in perfect condition. Flywheel was around £350 and I think clutch and slave cylinder were around £300 mark. Labour was free as my mate and I did it one Sunday Tricky without a ramp but not impossible


Sent from my moto g(7) plus using Tapatalk

 

[Cuprabenwytm]

Did it start squeeking prior to this as my clutch pedal has just developed an annoying squeek when lifting up

Sent from my MRD-LX1 using Tapatalk

 

[Jay5959]

Hi,

Having similar issues with my Leon 2015 2.0TDI, are you sure the Slave cylinder is a box out job?

Looking at the workshop manuals it looks as though it's external with a couple bolts and hydraulic line.

Started having issues a few months ago and had the Master replaced which seemed to fix but the past few weeks have been experiencing the same issues so was going to look at replacing the slave cylinder if anyone has any other ideas?

Does it feel the same as the original problem you were having? Seems strange changing the master cylinder would seem to fix it for a while. Might be worth bleeding the system in case you have air in the line.

 

[Kaiju]

Update.

So I changed the Master cylinder along with the clutch pedal assembly (comes as one, can't buy them separately) about 4 weeks ago and the problem was fixed.

But now the clutch pedal has dropped again! Surely the new master cylinder hasn't failed again as it was from TPS. is it just coincidence that the Slave cylinder may have also now failed??

 

[Jay5959]

Update.

So I changed the Master cylinder along with the clutch pedal assembly (comes as one, can't buy them separately) about 4 weeks ago and the problem was fixed.

But now the clutch pedal has dropped again! Surely the new master cylinder hasn't failed again as it was from TPS. is it just coincidence that the Slave cylinder may have also now failed??

It’s always possible that the slave has gone, they’re made of butter! Could always be an air pocket from switching the master cylinder, just guessing though?
Has it completely gone? Or can the pedal be pulled up and have pressure again?

 

[Kaiju]

It’s always possible that the slave has gone, they’re made of butter! Could always be an air pocket from switching the master cylinder, just guessing though?
Has it completely gone? Or can the pedal be pulled up and have pressure again?

Did a complete brake fluid replacement after we did the master to ensure there was no air etc and no fluid was lost.

The pedal is behaving exactly like it did when the master cylinder went. The pedal goes straight to the floor quite aggressively as the pedal assembly is on a spring. The pedal can be lifted back up again and it stays there due to the tension on the spring, but as soon as you touch it, it flings straight to the floor again

 

[Kaiju]

Yep it was the clutch slave cylinder. We could see where it had leaked when the box was out and when bleeding it you could hear air getting sucked back in.

Clutch, CSC and flywheel all replaced.

 

[Jay5959]

Ouch! Hopefully that’s sorted it now ?

 

[SuperV8]

Stupid design of 'modern' cars is the centre release clutch slave cylinder - was nothing wrong with a side mounted clutch slave which you you change in <30 mins.
clutch hydraulics do a full sweep of the bore each time the clutch pedal is pressed unlike brakes so have a harder time and can pick up crud which can make the piston seals leak/fail - so why on earth would you design it around the gearbox input shaft! so you have to remove the gearbox is beyond me.

My Audi A4 B6 clutch slave failed just before 200K and was a simple job to unbolt, fit new and bleed.

What did your DMF and clutch look like?
Did you/they measure DMF play? Was it withing spec? worn mutch?

 

[CLueless]

I was just checking in if I have to remove the gearbox in order to replace the slave. And yeah. This is really ingenious design. Grrrrrr. So for replacing a 40€ part I have to find a garage and either rent it for a day and risking that I will fck it up or pay someone 300€ for them to replace it. God have mercy on the person who came up with the idea to put this part in the gearbox.

 

[RUM4MO]

I thought, at least on the higher powered cars, the clutch fluid line from the master cylinder to the slave cylinder had a "damper valve" built into it, ie a form of one way valve which allows "full flow" in the direction of fluid being pushed down the release the clutch and had a restrictor slowing fluid in the other direction, ie to protect the fluid. My Audi S4 certainly has that as does higher powered Golfs and probably Leons and S3, and maybe more. The way these new cheap master cylinders are designed is unlike the older type in that there is no internal return spring to help the piston return to its "relaxed" position, that job is done by the spring on the clutch cylinder. So, it has been said on other forums, that when you have that fluid return "damper valve" and no return spring in the master cylinder, you can end up with the master cylinder piston and seal assembly being held down in the cylinder while the pushrod, which is meant to be fixed to the piston is being rapidly pulled back up and the result is that the pushrod parts company with the piston - and that is not handy!

If anyone knows better please speak up as I'm just passing on comments picked up from elsewhere - VW Group workshops just swop out old parts for new, but that potential weakness remains with no sign of VW Group understanding or bothering about it, which is just normal.

 

[SuperV8]

I thought, at least on the higher powered cars, the clutch fluid line from the master cylinder to the slave cylinder had a "damper valve" built into it, ie a form of one way valve which allows "full flow" in the direction of fluid being pushed down the release the clutch and had a restrictor slowing fluid in the other direction, ie to protect the fluid. My Audi S4 certainly has that as does higher powered Golfs and probably Leons and S3, and maybe more. The way these new cheap master cylinders are designed is unlike the older type in that there is no internal return spring to help the piston return to its "relaxed" position, that job is done by the spring on the clutch cylinder. So, it has been said on other forums, that when you have that fluid return "damper valve" and no return spring in the master cylinder, you can end up with the master cylinder piston and seal assembly being held down in the cylinder while the pushrod, which is meant to be fixed to the piston is being rapidly pulled back up and the result is that the pushrod parts company with the piston - and that is not handy!

If anyone knows better please speak up as I'm just passing on comments picked up from elsewhere - VW Group workshops just swop out old parts for new, but that potential weakness remains with no sign of VW Group understanding or bothering about it, which is just normal.

I think you're mixing up two different clutch hydraulic set ups.
Centre release clutch slave cylinders do not have push rods, that is the only benefit I can think or - more direct clutch activation - at the expense of difficult replacements requiring gearbox removal.
the clutch restrictors or clutch delay valves are mainly to help reduce driveline shock/stress.

your S4 has a remote clutch slave - with pushrod.
the MQB cars have centre release clutch slave

 

[RUM4MO]

@SuperV8, no, I was discussing the master cylinder not the slave, it is the push rod that touches the pedal I was talking about.