Thread: Brake failure

Sounds like the master cylinder is on its way out. With motor running and pushing pedal down & holding it down does it sink to the floor. If it does then the buckets are bypassing in master cylinder. Don't bother trying to rekit cylinder just put on a new one.
Hope this helps you
Rad

Originally Posted by Discomark

Hi Guys,

I am having intermittent brake failure on my non ABS Disco 1. It seems to be after the brakes are hot and started after a steep hill descent initially. i replaced the brake fluid and the issue seemed to go away. last week I changed the brake pads and after driving in heavy traffic for about 30k's the brake pedal went soft and almost to the floor with little brakes. Brakes returned to normal after cooling down. I was wondering if it could be the pressure limiting valve (ANR3194) or perhaps the master cylinder. Just wondered what the symptoms are when the limiting valve fails? any ideas?

Cheers

Mark

What year model Disco, my ex 93 Disco had same problem, turned out be that 93 disco front calipers have a bleed nipple on the outside of the caliper that can't be seen with the wheel on. My problem was that I replaced the master cylinder rubbers ($16) and bled the brakes and replaced all the fluid, BUT NOT the outside bleed nipples, which left old water contaminated brake fluid still in the system. After a workout the old fluid and water would boil away leaving no brakes until they cooled down again. If yours is a 93 with bleed nipples on outside of caliper, read the w/shop manual on the correct sequence for bleeding, if no manual let me know and I'll post up procedure, Regards Frank.

Originally Posted by Tank

What year model Disco, my ex 93 Disco had same problem, turned out be that 93 disco front calipers have a bleed nipple on the outside of the caliper that can't be seen with the wheel on. My problem was that I replaced the master cylinder rubbers ($16) and bled the brakes and replaced all the fluid, BUT NOT the outside bleed nipples, which left old water contaminated brake fluid still in the system. After a workout the old fluid and water would boil away leaving no brakes until they cooled down again. If yours is a 93 with bleed nipples on outside of caliper, read the w/shop manual on the correct sequence for bleeding, if no manual let me know and I'll post up procedure, Regards Frank.

Hi Frank, its a 97 model so not sure if its got the hidden nipple!
Cheers
Mark

Originally Posted by Rad

Sounds like the master cylinder is on its way out. With motor running and pushing pedal down & holding it down does it sink to the floor. If it does then the buckets are bypassing in master cylinder. Don't bother trying to rekit cylinder just put on a new one.
Hope this helps you
Rad

Thanks Rad, Its looking more like a master cylinder issue so I will probably pick one up from Karcraft for around $250 and just change it anyway, car is 13 years old so is probably due for new seals regardless.
Cheers

Mark