Braking power suddenly disappears

[peasjam]

The brakes on my FD seem to have developed an intermittent issue where I loose 80-90% of my braking power.

Brakes feel absolutely fine most of the time and the peddle feels normal. Sometimes however it\'s as if my brakes are barely there and the feel of the peddle changes slightly. This can \'come on\' while brakes are already applied.

Any ideas what this can be? It\'s just been MOT\'d so pads and discs are fine, it\'s intermittent anyway which I think suggests a problem elsewhere.

Thank you,
Matt.

[Aubec]

Fluid could be waterlogged, get it changed.

[shaunwil]

Check the One way valve in the vacuum line too between the UIM and the brake master. Could be a knackered vac assist !

Shaun

[m1tch]

Perhaps check the bottom of the brake booster, perhaps its got a rust hole meaning it isn\'t assisting the brakes?

[carlbrainiac]

Is it only when braking hard? Could just be the ABS kicking in. Thats one thing that annoys me with my Subaru. Stupid ABS cuts in WAYYYY too early. Drives me nuts. Almost tempted to pull the fuse lol. Havent had the ABS cut in on the rex yet.

[peasjam]

Cool, I\'ll check the things suggested. It\'s definitely not ABS, never had it before.

[SiH]

Check the One way valve in the vacuum line too between the UIM and the brake master. Could be a knackered vac assist !

Shaun

My money\'s on this The pipe isn\'t that expensive.

[Indian]

it sounds like your Master Cylinder might be going. You want to check your ABS motor too. bridge the relay and see if it turns on