MK5 Golf GTI

All Things Mk5 => How to Guides / Troubleshooting => Topic started by: Johnsy on May 09, 2016, 04:31:34 pm

Title: Brake/clutch fluid boiling -symptoms
Post by: Johnsy on May 09, 2016, 04:31:34 pm
is it possible that boiling brake/clutch fluid would give me a soft/lower clutch pedal?

Iv got the ttrs brembo s fitted with £50 pagid pads on 340mm discs,standard fluid ( mk2 LCR stage1) I was out up Alston having a hoon with my mates, it's a roller coaster of a ride on the way there from sacriston, went down/up the pass, at the bottom the clutch pedal went a bit limp and the bite was near the floor same again at the top,parked up and went down in my mates Meg , thinking it can't be the clutch as its not slipping, got me thinking the brake fluid is coming upto 4yr old and needs refreshing ,
Anyway ordered some Motul rbf 660 fluid from opie which arrived today so that's getting swapped out on Wednesday, so I'll know for sure .

Thought this might have come up before but couldn't anything
Title: Re: Brake/clutch fluid boiling -symptoms
Post by: r5gtt on May 09, 2016, 09:25:22 pm
Could be a failing master cylinder leaking behind the pedal or concentric slave cylinder leaking in the box as boiling the fluid shouldn't really change the clutch feel.
Title: Re: Brake/clutch fluid boiling -symptoms
Post by: pudding on May 10, 2016, 10:31:58 am
4 years is quite old for brake fluid, but it can be tested by any competent garage for moisture content.   Get it changed and see if it improves matters.  I take it the pedal feels firm normally?
Title: Re: Brake/clutch fluid boiling -symptoms
Post by: Johnsy on May 11, 2016, 06:29:02 pm
Had the Motul fluid fitted today, it's certainly improved my brakes, and my clutch pedal travel/feels a little better, but can't help think the bite was a lot higher,and the initial couple inches of travel on the clutch less floaty(best way I think to describe it.

Anyway how much fluid would you use? I thought a litre after watching a video on YouTube,and ordered 1.5l, they've used less than 500ml and didn't bleed the clutch, which I told them was my main reason for doing this :slap:.

I had thought initially that it was the slave cylinder,but couldn't find any evidence of leaking oil around the bell housing,and the friction plate isn't slipping through contamination and it sort of got better until that hoon in the hills,
Title: Re: Brake/clutch fluid boiling -symptoms
Post by: r5gtt on May 11, 2016, 07:17:29 pm
Might need a clutch bleed?.
Title: Re: Brake/clutch fluid boiling -symptoms
Post by: Johnsy on May 11, 2016, 08:02:16 pm
Might need a clutch bleed?.
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Yup, I need to know its 100% not the fluid before other avenues are explored
Title: Re: Brake/clutch fluid boiling -symptoms
Post by: The Wanderer on May 12, 2016, 07:47:24 pm
I had a similar issue, I had new discs fitted and my brakes bled but the garage did not bleed the clutch.

On track when hot, i found it difficult to get gears. Had the clutch bled and found black brake fluid.  Clutch feels way better but not tested on track yet.
Title: Re: Brake/clutch fluid boiling -symptoms
Post by: Johnsy on May 12, 2016, 10:25:29 pm
I had a similar issue, I had new discs fitted and my brakes bled but the garage did not bleed the clutch.

On track when hot, i found it difficult to get gears. Had the clutch bled and found black brake fluid.  Clutch feels way better but not tested on track yet.

Same result here, bled the clutch tonight and it was black, got my original Pedal/bite back after flushing the Motul fluid through , I'm well chuffed it's not often issues are simple fixes .
Title: Re: Brake/clutch fluid boiling -symptoms
Post by: r5gtt on May 12, 2016, 10:27:46 pm
 :partywave: