E30 Brake Booster and Master Cyclinder

[antonvh]

So I had a near accident the other day and while trying to slam on brakes, felt something give and since then (luckily avoided the accident), the brake pedal would not return to top position and brakes are spongy.

I thought that maybe the master cylinder seals went so I overhauled it. Must say that if I had the money I would have liked to replace the cyclinder as it has a small area with marks in it.

It made no difference though, now I am wonderring is the system not blead properly or is it the marks in the cylinder......and then there is one more thing...I have now also noticed that when I press the brakes there is a hissing sound from the brake booster inside the vehicle.

I have performed the subcribed test on the booster and it seems fine but is it?? Mabe the valve in the booster went and that is why the brakes are spongy?>

I will have to start all over again

 

[Nic_s]

Could be that the brake fluid got cooked and there might be some air bubbles in the lines. A full bleed and new brake fluid should take car of any air bubbles.

As for the sound, is it a kind of "whoosh" sound. Mine does the same, but I always assumed it's normal. When I had my rear drum brake pads replaced the guy who worked on it didn't say anything and he was thus far the best BMW mech I ever knew. So I think it's normal :mmm:... I do need new discs and brake pads at the front, but it all still works fine.