vrs brakes

[funkymonkey]

how do i check my master cylinder is ok my brakes aint as sharp as they used to be, i have tried it this way is it correct

with engine off pump up pedal till hard and hold for 15 sec or so (pedal went hard and did not drop at all ) with engine on pump pedal again and hold (this time is does not go hard but does not drop after say halfway ) is this how it should be

[Volvomeg]

Have you had a check round at your brakes, are all the discs and pads ok as the fronts tend to rust up on inner edges if not given some stick every so often

[funkymonkey]

all discs and pads are fine no leaks on the callipers either, brakes work fine just don't have the same bite as the used to there less sensitive, i have bled them and the master cylinder which helped as the were really spongy before there seems to be more pedal travel before they bite now

[rk696]

It sounds like the MC is probably OK if it doesn't creep down when pressed hard. Are any wheels hotter than the opposite side after driving? You might have a seized or sticking caliper.

Try a few hard stops from motorway speeds to about 5 MPH to get them hot. Stop when you start to hear them groaning. You will find the brakes will be awful after that, but they usually come back better than ever I've found. If you do this though, make sure the brakes cool down before you stop as you can cause brake vibration.

[kentphil1]

Have you checked the vacuum pipes for the servo are ok?, also is the pedal box mount where the servo mounts and also where the master cylinder mounts on moving at all?. Servo is obviously working as the pedal sinks when you are pressing the pedal after the engine fires.

[MR G]

Has the fluid been changed? If not mite be worth trying that

[niceyellow vrs]

Has the fluid been changed? If not mite be worth trying that

I'd second that. Surprising how much difference fresh fluid makes.

[kentphil1]

Think he said in post #3 that he bled master and calipers, but like you say that does not necessarily mean a complete fluid renew. Could be worth checking the flexible hose condition as well for swelling under load.