Club 80-90 Forums

Hi,
My van has just randomly decided to not have any brakes, the pedal goes straight to the floor with no resistance at all. The van isnt on the road yet and is only ever moved back and forth on my drive so the brakes havent really been under any pressure so im not really sure whats happened. Fluid levels haven't dropped at all.
Ive checked the vacuum hose and non return in the engine bay and I cant see, hear or feel any leaks. The odd thing is when the engine is ticking over and I press the brake pedal to the floor the engine splutters and almost cuts out.

I was going to just replace the master cylinder but im confused about the enigne cutting out when the pedal is pressed?

Servo fault
Master cyl seals

Block off the servo vac pipe as close as you can to the carb/manifold and if this clears the sputtering fault then you have a vac leak somewhere. Although you should have some brakes without the engine running so...
CS

leaking wheel cylinder?

Thanks for your replies. Im going to look into this a bit more in depth tomorrow but I have a replacement master cylinder, I remember reading somewhere online about bench bleeding the master cylinder before fitting. is this necessary?

I remember changing a master cylinder on a Vauxhall chevette (showing my age now) when I was a lot younger than I am now. I bench ‘primed’ the master cylinder otherwise you introduce masses of air in the system. This doesn’t matter really as you will then bleed the brakes. Just it will take ages to do without priming first.
As to you original problem, if the fluids are fine then o honestly have no idea - sorry

Thanks for your replies, I skipped the bench prime and just fitted and filled as I plan on bleeding the whole system anyway. however I left it overnight and have just looked this morning to find a few drips of fluid.
it seems its leaking from the one of the brake switches, but actually through the switch and out through the terminals!? so I will replace both switches and do a full bleed and see how I get on.

I know I probably should have replaced the switches anyway but I was trying to cut cost and honestly thought they would be fine.

Well.... I fitted the new switches only to find I still had a slight leak around the switch. on closer inspection I could see a hair line crack so I obviously decided to remove the new MC to look closer at what had caused it to crack and when removing the switches the thread literally split in half. any ideas on whats happened? I honestly have no idea, as the switches cant be over tightened as they come to stop and dont allow overtightening. is the new master cylinder just of really poor quality and made out of biscuit?

see photo below


https://www.dropbox.com/s/dawy57wj47dhf ... r.jpg?dl=0

According to this you can over tighten and cause it to crack.
https://club8090.co.uk/forum/viewtopic.php?t=162785" onclick="window.open(this.href);return false;

The hole doesn't look very central in casting, bit of a give away to the quality?