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Bizarre brake failure (and miraculous cure) - Any ideas?
Posted: 15 May 2006, 19:58
by NeedABus
Had my brakes fail on the way home
20 miles into my journey the pedal went very spongy and very little happened.
When I stopped (to change my underpants!) I realised I had been driving with the handbrake 2/3 on.
The AA brought me home.
An hour or so later I checked the vacuum hose was OK (it's a 1.6d), and there was a wooshing noise as I removed it, convincing me there was a vacuum, and I took it for a drive and the brakes were fine.
So ..... could driving with the handbrake on cause my brakes to fail, then when it all cools down they be fine again?
I'm totally confused.
Posted: 15 May 2006, 20:04
by TechtroT25
Maybe you boiled the fluid just a thought
yes
Posted: 15 May 2006, 21:00
by billy739
yes the brake fluid boiled due to the heat inside the drum.
in a perfect world you should change the brake fluid and check the brakes as you have probably burnt the linings and possibly the rubber seals on the cylinders and although still working ,effciency can be low
you brake fluid should be changed every 2-3 years as it attracts water (hydroscopic)thus it will boil easier when old(more water) and cause fade sooner!
Posted: 15 May 2006, 21:05
by NeedABus
All sounds reasonable.
I think I'll change the fluid, then get the MOT station round the corner to do a brake check for me.
Posted: 16 May 2006, 21:12
by Sir Chad
Slave cylinder seals should be OK, I lose all breaking regularly on trackdays due to overheating (not in the wedge!) and seals/hoses have never been a problem, changing the fluid is sensible - regular brake fluid slowly absorbs water, which is compressible, making your pedal more and more spongy - it also turns to steam when you cook your brakes, making the pedal dissappear very quickly.
Chad
Posted: 16 May 2006, 21:25
by NeedABus
I'm paying the MOT place £20 to change the fluid. Lazy I know, but I've just saved the best part of £500 changing the head gasket myself so I'm indulging myself a little with this.
Posted: 16 May 2006, 21:38
by Ivor Brownun
don't blame you, it's all that bleeding bleeding, does yer ed in
Bizarre brake failure (and miraculous cure) - Any ideas
Posted: 16 May 2006, 21:54
by Bowton Lad
Sir Chad wrote: regular brake fluid slowly absorbs water, which is compressible, making your pedal more and more spongy
Chad
I agree with most of what Sir Chad says except the bit about water being
compressible. One of the properties of water is that it is 'virtually incompressible'.
Posted: 16 May 2006, 22:01
by Sir Chad
I've got an easybleed and a 18v cordless impact wrench for getting the wheels off quickly, so it doesn't take too long. But more importantly I just don't trust garages to do the job properly.

Re: Bizarre brake failure (and miraculous cure) - Any ideas
Posted: 17 May 2006, 10:24
by purplechugster
Bowton Lad wrote: One of the properties of water is that it is 'virtually incompressible'.
And that's the reason why belly flops
really hurt

Posted: 17 May 2006, 10:40
by Mocki
so how come only TC can walk on water then?
Posted: 17 May 2006, 12:10
by Diamond Hell
It's cos I move my feet really quickly - so quick you think they're moving slowly, see. Keeps me afloat, innit.

Posted: 17 May 2006, 21:59
by NeedABus
Fluid is changed ... all seems fine, in fact better than before.
We'll see what 40 miles to work does to it ..................................