Master cylinder
 

Hi there I have a standard 3 port master cylinder 2at the back and 1 at the front side am I right in thinking the back 2 are for the front brakes (1each) then the front port are split for the rear brakes the reason being its the only thing I can think of why my brakes won't bleed up all components are brand new no leaks etc the only way I can get any sort of brakes is if I pump them about 10 times any advice would be much appreciated

Is your master cylinder the same as this one ?



If so, the 2 ports visible at the front go to the front brakes ( 1 port per front wheel )
The rear single port ( Hidden from view in the picture ) goes to the rear wheels & is normally split with a T piece at the rear end of the car.

Don't know if you are using a new master cylinder, if not, it is not uncommon for the internal seals to fail after a prolonged period of storage ;)

I chose to alter the angle of my master cylinder so as the fluid reservoir would sit a bit more level & as an aid to help prevent airlocks in the cylinder.

If you are unable to get any brake fluid moving, I would look towards the master cylinder first.

Seem to remember that AshG had a faulty master cylinder & that was a brand new unit.

Perhaps this is of some help to you :)

If you have a solid pedal once you have pumped up the brakes its not air. I noticed you are on drums so it could be the self adjusters have not taken up the slack yet. If its is air just buy one of those two bob pressure bleeders that will shove all the air out. Anyway whats this thread doing in here its like finding screwdrivers in the spanner draw.

bob

few things can be a problem here.
the roadster std design puts the master cyl very low in the car so bleeding has no down hill syphon effect that can be made harder by pipe routeing higher than the master cyl and puting things like hyd brake switchs in a way that thay trap an air pocket/bubble.

a good tip is to prevent suck back as much as possible and if you have an unsealed union it could take all day.

check all your unions are tight ptfe or red grease your nipple threads and bleed the master cyl at its pipe unions first and see how you go.

i have a top mount style pedal box and i just opened the nipples waited for gravity to do its thing and watch for drips at the nipples tighten them all up and it was done :D

Is there a way to check the seals on the master cylinder are ok prior to instalation? I'd hate to go through loads of hassle trying to bleed it only to find out the seals are gone like Ashg...

http://www.ebay.co.uk/itm/ONE-MAN-Br...em2 562776dd4

You just cant beat these cheapo bleeders. I have never been a fan of stamping on a pedal to drive out air from the system. On those dual circuit systems when bleeding say the fronts the rear portion of the master is running best part of dry and thats when it all goes tits up. The piston can get stuck at the top of its travel and its game over. I am not saying it cant be done the conventional way but these pressure bleeders save time, fluid and grief.

Bob

Thanks
 

thanks for all the info people i have checked all unions etc every compnent is brand new the wheels do lock up after you pump the pedal about 10 times i think i might buy myself one of those bleeders and have a go at that

One thing that is worth trying is unbolting the caliper and sitting it on its side so the bleed nipple is high and bleed brakes again as I had this problem once and that was also with all new parts.