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Author Topic: Lots of air bled form the clutch?  (Read 1300 times)

Offline Clarkj93

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Lots of air bled form the clutch?
« on: April 09, 2022, 12:23:45 pm »
So did a brake fluid change today from euro car parts best to Motul rbf 660. Ran the abs pump first then I used a 1 man brake bleeder as I have done a fair few times, walked off a few times and bled a bit more than usual (250ml FL, 300 FR, 400RL, 350RR) by accident but thought nothing of it as there was 2 litres in the 1 man bleeder. All going smoothly not much air at all as expected coming out.

Then went to bleed the clutch and a fair bit came out! I wasn't sure if the hose was coming loose from the clutch nipple but didn't look or feel like it. I held it down lightly a few times but not sure if this contributed/helped at all. After draining about 100ml out after the air bubbles seemed to stop for an ok amount of time I closed the nipple and pumped the clutch a few times (felt OK) then opened the nipple and drained another 50 or so ml out and again quite a bit of air came out, again after an OK amount of time of no air coming out I closed and thought time to test it.

So got in it and the clutch did feel light, like it had almost a dead spot at the start of depressing it. After a few pumps it felt good again.

I checked the bleeder and there was not much fluid left in there at all but still looked like the hose would be in contact with the fluid unless it was at a really weird angle which it definitely wasn't so seems unlikely that it could have pumped air into the reservoir.

Driving the car the clutch feels fine and brakes feel fine as well, doesn't feel like there is air in the system at all, all feels tip top.

I've changed the fluid 3 times before this in the last few months doing various minor brake jobs and I've never once seen so much fluid come from the clutch! Seems odd to me and not sure whether to go Bleed them again, spent so much on fluid lately I'm fed up of buying the stuff :grin: anyone have any idea why that could have happened?

Offline LC5F

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Re: Lots of air bled form the clutch?
« Reply #1 on: April 09, 2022, 01:04:02 pm »
My Mk5 is a DSG, so cant claim to know this issue, but from other VAG experience I can say that:

Usually the connection of the the brake fluid reservoir is higher up the reservoir, this is a safeguard in case the clutch line fails it does not take out the brake fluid too - I suspect you may have emptied the one-man and the reservoir level dropped below the clutch outlet.

Is this the first time bleeding the clutch? - very often the clutch gets ignored for multiple years, fluid within the line gets in a real mess, new fluid will be a lot smoother/lighter.
The dead patch may just be a bubble of air within the master cylinder, hopefully it has worked its way out.

Clutch lines can be real stinkers to bleed, if possible, for greatest chance of success its best to do the clutch first before the rest of the brakes but reverse bleed the clutch from the slave back up to the reservoir - the fluid will push in the same direction the air bubbles want to go, all the cruddy old fluid will end up in the reservoir, suck this out with a turkey baster.



Offline Clarkj93

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Re: Lots of air bled form the clutch?
« Reply #2 on: April 10, 2022, 02:47:34 pm »
My Mk5 is a DSG, so cant claim to know this issue, but from other VAG experience I can say that:

Usually the connection of the the brake fluid reservoir is higher up the reservoir, this is a safeguard in case the clutch line fails it does not take out the brake fluid too - I suspect you may have emptied the one-man and the reservoir level dropped below the clutch outlet.

Is this the first time bleeding the clutch? - very often the clutch gets ignored for multiple years, fluid within the line gets in a real mess, new fluid will be a lot smoother/lighter.
The dead patch may just be a bubble of air within the master cylinder, hopefully it has worked its way out.

Clutch lines can be real stinkers to bleed, if possible, for greatest chance of success its best to do the clutch first before the rest of the brakes but reverse bleed the clutch from the slave back up to the reservoir - the fluid will push in the same direction the air bubbles want to go, all the cruddy old fluid will end up in the reservoir, suck this out with a turkey baster.

No I've bled it multiple times that's what strange. Yeah that must be the cause, seems OK, will maybe just do a quick Bleed just to double check if I get bored one Sunday, it does feel fine anyway. Cheers!