brakes

[Guest]

stag due 1st mot in two and a half years or rebuilding suddenly brake pedal works at first then goes to the floor could it be my servo unit? any help please

[StagnJag]

Certainly not the servo, the brake pedal should never go to the floor. It is air in the system or a fault with the master or slave cylinders.

Is it loosing fluid?

If not, my hunch would be that the seals in the master cylinder are kaput.

Rgds

Dave

[lardystag]

i havnt lost any fluid any way to test the master cylinder do i try to reseal it or fit replacement cylinder?

[Andrew S]

I agree with Dave's comment, its the master cylinder. You will be losing fluid with no signs of leaks as the fluid will be going into the servo unit. Dont re-seal it, get another one new.

[milothedog]

i havnt lost any fluid any way to test the master cylinder do i try to reseal it or fit replacement cylinder?

With the engine off, hold the pedal down for an extended period of time, if it sink's (slowly goes down further) then the M/Cylinders seals are shot.

Ian.

[StagnJag]

It isn't worth replacing the seals, they don't last long as the reason they go in the first place is because of corrosion in the bore (and old age!).

Rgds

Dave

[martin]

It is possible to reseal the master, but unwise, after all that graft, if the bore isn't perfect you'll have to replace it anyway. When you have it, and the servo off, wash the servo out with warm soapy water then rinse, that gets rid of the old fluid. Do buy carefully, some M/Cs on the market are re-built with new old stock seals, shortly after fitting, you'll find the fluid turning black as the seals dissolve. Martin.

[Guest]

It's the master cylinder, get a refurbed one with a stainless steel piston, it shouldn't corrode again.

Jason