Bizarre brake failure (and miraculous cure) - Any ideas?

[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.

[TechtroT25]

Maybe you boiled the fluid just a thought

[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!

[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.

[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

[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.

[Ivor Brownun]

don't blame you, it's all that bleeding bleeding, does yer ed in

[Bowton Lad]

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'.

[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.

[purplechugster]

One of the properties of water is that it is 'virtually incompressible'.

And that's the reason why belly flops really hurt

[Mocki]

so how come only TC can walk on water then?

[Diamond Hell]

It's cos I move my feet really quickly - so quick you think they're moving slowly, see. Keeps me afloat, innit.

[NeedABus]

Fluid is changed ... all seems fine, in fact better than before.

We'll see what 40 miles to work does to it ..................................