Brake Frustration

morning all. I thought my winter project was ready for MOT untill i finally filled and bled the brakes. New cylinders on the rear, new pistons and seals on the front, most of the pipe replaced, after sorting out all the leaks the pedal felt good n hard untill i started the engine, then pedal pulled down as it should about an inch on the servo, but under normal braking pressure, pedal slowly descends!! I checked for leaks but found none. Logical thought at this stage indicated master cylinder seals which i promptly ordered plus o/nite carriage. However, these have made no difference. Do i need a new master cylinder? I can see no obvious signs of wear in the bore but have no means of measuring. I can live with knackered engine and bodywork but i do need good brakes! thanks

Is the vaccum pump working properly?

yes - vacuum pump is working ok - i took pipe off and stuck part of my anatomy over the end - good suction!!

how are your hub bearings? if their worn/loose/shot to **** then the pressure on the brakes can be taken up on the bearings under braking.

G

Hubs are fine - this prob is when I am stationary so hub/disc wobble not really an issue, it just feels like a minor fluid leak as pedal slowly goes down under moderate peddle pressure with the engine running, with no servo working, pedal feels rock hard

replacement seals rarely work in my experience, just get a new master cyl.

Did you refit the shoe return springs on the rear drum brakes correctly? "Correctly" is from the leading shoe to the post on the backplate, not between the two shoes. I know this from bitter experience

Thanks guys - im sure brakes are asembled ok - i have new master cylinder on order