Weird brake problem

[FridgeFreezer]

Speaking to a chap last night who has a bit of an issue with the brakes on a lightweight - new shoes all round, adjusted up, system bled fine but no matter what you have to pump it about 4 times to get a pedal and if you start the engine you have no brakes at all

Aparrently if you clamp the rear flexi you do get a pedal, but not with the engine running. (It has a servo and has just had a new master cylinder)

Now I don't know a lot about 'em but I reckon there's two problems - one with whatever's been done to the rear brakes (shoes in the wrong way perhaps?) and one with the master cylinder.

The chap who did the master cylinder threw the old one away so there's no way of checking that the one he's got is correct. I know the dual circuit servo ones have several permutations of cylinder & plumbing but I can't recall what they are.

Anyone got any pointers?

[Tonk]

u can use either master and it will bolt on, later ones are better, just need to make sure that the large union/outlet is plumbed to the front brakes.

[bill van snorkle]

Some people, even mechanics,mistakenly attach the top brake shoe return spring to the trailing shoe (shoe without snail adjuster) instead of the leading shoe (shoe facing forward with adjuster) This will cause the wheel cylinder piston for the trailing shoe to be retracted fully into the cylinder every time the pedal is released, and if the same mistake has been made at all 4 wheels, several pumps of the pedal would be required before the shoes touch the brake drums.

Bill.