Discovery 1 Brake Problem... HELP!!!!

I have a N reg, Disco 1. The brakes have completely failed on 3 separate occasions. Each time it has been diagnosed as a master cylinder problem which has been replaced twice.

The problem appears to be rectified but reoccurs after a few weeks. When the brakes fail they partially recover after a few minutes. I have had the brakes checked, there are no leaks and the pads and discs are in good condition.

I cannot believe 3 master cylinders have been faulty so I think the problem may be something else.

Anyone any ideas as I cannot drive the disco currently for fear of this happening again and not being so lucky next time

Disconnect the ABS and see if it does it again. Pull the fuse or relay or the plug on the modulator.

Does the pedal go all the way down when it fails?

Hi Dave,
Thanks for comments.

The brake pedal goes to the floor and does not recover on pumping.
However 1 or 2 minutes later it recovers and the brakes work again.This has happened three times with a six week interval between each failure.
Weird and very scary.

Cheers Colin

Ok if pedal goes down, not likely to be the abs. It does very much sound like master cylinder but I can't see why it should eat them.

The last replacements weren't britpart were they??

Thanks Dave,

Am I right in assuming that the problem I have could only be the master cylinder or the ABS block(either pump or seals)???

Cheers Colin

Have you ever changed the brake fluid completely?
Sounds as though your problem could be heat related. Water in the brake fluid turning to vapour would cause brake failure as you describe and would recover as the vapour condensed again.
Just a posibility.
I don't believe 3 master cylinders have failed even if they were Britpart.

Dear all
I have a similar problem. When on down hill say 8 to 10 km or so my brakes fails. The pedal goes down to the floor and I can only get the brakes after pumping three or four times.
It takes about 15 to 30 minutes after down hill descend for brakes to recover.
I have replaced 3 master cylinders but the problem persists. Please help.

Sounds like you could do with a brake fluid change, is it black/dark in colour?

It could be wheel bearings!

If they're loose, or the inside races broken, they 'move' the discs such that the pads are forced into the calipers and it appears to need bleeding, or pumping, to get the brakes working again.

Check, or have someone check, the wheel bearings 'properly' .. take the wheels and hubs off so you can physically remove the bearing cages and see the races in the hubs. Any damage can exascerbate the problem, but make it 'feel' fine when doing a normal bearing check of just wobbling wheels!

Any doubt replace them all with Timkens .. trust me on this!

I'm going for contaminated brake fluid. Get it fully bled as a matter of urgency.
Griff