Just called my local VAG repair shop about having my brake fluid changed, I also asked if they did the clutch as well they said no, as they have had problems in the past when changing the fluid for the clutch, such as slave cylinders needing changing after they have done it. What are your thoughts on this, is it a problem and does the fluid really need changing for the clutch?. Thanks.

Not familiar with the Mk2 - but does your car have separate fluid cylinders for brake and clutch? The mk3 shares the fluid for both systems.

Probably not necessary to change the clutch fluid if it is a separate cylinder though.

Have you had the brake fluid tested to see if it is actually necessary to change - or are you simply following recommendation? 

Edited 26 November, 20241 yr by Warrior193
typo

The clutch and brake hydraulics are a common reservoir. It is a simple case of opening the bleed nipple. 

If they think it is difficult go and talk to someone else, Their comment suggests a lack of competence.

I changed both when I had my Mk 11.

It's easy to do but I can see exactly where they are coming from, if you have a 6 speed gearbox it is not a question of will the clutch hydraulics fail but when? operating as they do they protect themselves from the "it was working fine until you bled the system"

 

I would definitely bleed the clutch as well but in the position of a garage would refuse to do so.

56 minutes ago, krisp1 said:

I changed both when I had my Mk 11.

Are you from the future?😄

I've always bled the clutch too while I've had a pressure bleeder attached to do the brakes.

Never had any issues, but what if say the bleed nipple broke off. However unlikely that may be, who takes the risk.

The clutch can be more of a pain to bleed. Brakes, up on the ramp and the bleed nipples are there to go around all 4. The clutch you often have to take airbox and sometimes the battery out to access it.

I don't see why a garage would not do though if you actually request it to be done.

1 hour ago, aubrey said:

I've always bled the clutch too while I've had a pressure bleeder attached to do the brakes.

 

 

Unless i'm missing something, and forgive me if I am, but using a pressure bleeder on a concentric slave cylinder, or indeed any slave cylinder to some extent, is not actually doing anything but renewing the fluid down the pipe to the bleed nipple. (i'm not saying this is a bad or pointless idea btw, you might as well get as much fresh fluid in there as you can)

 

But to truely bleed a cylinder that is full of fluid, it needs to be stroked multiple times to get the old fluid out as it is essentially a blind hole with no actual flow through it (unless the piston is moving). The only way to really change it effectively is to remove it, try and drain it, and then refit it and bleed up again, otherwise you are just pushing the old fluid backwards and forwards with no real way of getting fresh fluid down the neck and to the cylinder and nobody is taking a gearbox off to change the fluid is a slave cylinder.

Edited 26 November, 20241 yr by SuperbTWM

My last manual car, a Roomster 1.9 PD, didn't have a concentric slave cylinder. But I understand your point. My current vehicle is a 1.2 Yeti DSG, so obviously no clutch bleeding on that.

So reading up now on how you do indeed bleed concentric slave cylinders gives me even more reasons why a garage would avoid doing the task unless specifically instructed to do so.

It was a shame they got rid of the older style slave cylinder, sure was an wasy job to change one of those in comparison.

 

 

14 hours ago, SuperbTWM said:

 

Unless i'm missing something, and forgive me if I am, but using a pressure bleeder on a concentric slave cylinder, or indeed any slave cylinder to some extent, is not actually doing anything but renewing the fluid down the pipe to the bleed nipple. (i'm not saying this is a bad or pointless idea btw, you might as well get as much fresh fluid in there as you can)

 

But to truely bleed a cylinder that is full of fluid, it needs to be stroked multiple times to get the old fluid out as it is essentially a blind hole with no actual flow through it (unless the piston is moving). The only way to really change it effectively is to remove it, try and drain it, and then refit it and bleed up again, otherwise you are just pushing the old fluid backwards and forwards with no real way of getting fresh fluid down the neck and to the cylinder and nobody is taking a gearbox off to change the fluid is a slave cylinder.

 

Never use a pressure bleeder on a concentric slave cylinder that is for sure.

 

The cylinder is self bleeding, any air will rise to the bleed block AKA peak torque limiter, there is a void (think of an airspace in a flooded cavern) just underneath the thumbscrew bleed nipple, you open that and any air is expelled in a couple of seconds by the hydrostatic pressure from the reservoir.

 

You are correct that there is no way to actually flush the fluid out of the slave cylinder.

 

16 hours ago, aubrey said:

what if say the bleed nipple broke off.

 

It won't unless you are a gorilla or a robotic actuator arm, the bleed nipple is a knurled plastic thumbscrew threaded into a plastic housing.

Thank you everyone for your very interesting input, certainly something to consider.