Why Can't I Keep No Friggin Brakes???

[zed]

Originally Posted by TerryS

That's a good point. Junk can accumulate in the back end of the MC over years , and not be a problem until the check valve is forced into it and, when the junk gets caught beneath the valve. He did, however say that it does build and hold pressure after succesive pumping, which would indicate that hasn't happened (yet).

Well.. I think I may have the exact same problem as he does.
I am not 100% sure if I have ALL of it tracked down.

I was bleeding a brake,.. all of a sudden the pedal stuck half way. It will build pressure then all of a sudden quit on me and sink to about 2 inches off the floor. No fluid coming out, on what is supposed to be, and looks like a new master cylinder.

The more I played with it, the louder the hiss got.. till the car started having trouble idling. Seems that my booster has gone bad, seemingly from bleeding the brakes. Don't know why.. I don't even know how they work.

Start your car and pump your brakes...see if you get a hiss.. Push hard.

[turretman1st]

WHAT ARE THE MASTER CYL/ BOOSTERCYL and WHEEL CYL MADE OF
i have not actually looked at rover mech yet
but most of experience is british like aluminum and american brake fluid is incapatible with aluminum it cosses masive corosion
this corosian will be below the normal working area of the cylinders ON bleeding most often you push your piston past this point damaging seals.

if you have not rebuilt or replaced master cyl ALLWAYS PLACE SOME THING BEHIND PEDAL SO IT WON"T GO PAST THAT POINT WHEN BLEEDING

some times its not bad and will hold for a short time then bypass the seal if an edge is held up on some corrosion.

my experiance with them is to use a presure bleed wheel cyl to master with aluminum brake hydraulics.

best practice is to always clean rebuild cyl when brake work done.

hope this helps
bill

FORGOT TO ADD IF YOU USE PRESURE BACK BLEEDING HAVE SOMETHING TO CATCH OVER FLOW
HELL ON PAINTED SURFACES

[zed]

Turns out those diaphragms just won't last if they get wetted with brake fluid or become 35 years old.

Mine did both.. still curious to find out what wedge discovered.