brake pressure fade

[sideshow]

20 years of working on cars u sometimes run into problems with bleeding brakes and I remember some days u spend half a day getting a good pedal on a customers car
It wrecks your brain trying to figure out what could be wrong

[Zedn]

Originally Posted by AC-460

your displacements are incorrect...... Your problem is what you first suggested.... if you don't have a dual master cylinder setup eg one for front one for rear with a balance bar and you are relying on a single master cylinder your displacements are wrong eg your rears are locking up because your master cylinder has supplied more fluid to the rear than the front..... you need to fit a proportioning valve to bleed off pressure to the rears.... or reduce the piston size of the calipers on the front..... or increase the piston size of the calipers on the rear

The setup he has is tried and tested in many cobras. There may be variations, under actual braking but that would be due to weight distribution. If at full brake he can turn the wheel by hand then there is a problem with this set up that works on other cars.

[renovationinnov]

as said before i found that the calapers when i took pics where fitted the wrong hand when i reassembled them i did it again '' so now i have swapped them & today ive got the new brake lines so i'm at the misses mercy to help bleed again
tried to find a vaccum bleed system today but no one stocks them there order in only so ill buy a one man bled system tomorrow then
if the problem persists ill try all that has been suggested
let you all know soon thanks
ROB

[Jaydee]

or increase the piston size of the calipers on the rear

Increasing the piston, means larger surface area, means more force is applied to piston. Larger piston in master cylinder is more fluid, less pressure.
JD

[Zedn]

i got a one man bleeder for about $15 from super cheap. It is a hose with a one way valve on it so you hook it up and just pump.

[AC-460]

Originally Posted by Zedn

i got a one man bleeder for about $15 from super cheap. It is a hose with a one way valve on it so you hook it up and just pump.

What about the air drawing in through the thread on the bleeder?????

[Legless]

Originally Posted by AC-460

What about the air drawing in through the thread on the bleeder?????

Though slightly different, this is also the problem with vacuum bleeders I reckon, while they have a use I still think there's no substitute for pushing the brake peddle.

[Gav]

With a vacuum bleeder it won't matter if it sucks a bit through the bleeder thread.
I reckon you are clutching at straws thinking that was an issue.
I found the vac' bleeder to work well with any brake system.

[renovationinnov]

well people I have had success I bleeding , after a few leaks [ retightened all connections we have brakes
I bought a self bleeder unit & a one way valve from repco which failed
tried super cheap [ name says it all ] which failed
so Sunday flee market found a old workshop unit $24 , cleaned it up & wolar brakes
thanks for all the incites
ROB

[renovationinnov]

just an up date i got home ready to put the wheel on & sit it on them but all i found was brake fluid every where
a brake hose had broken at the crimp flange thread [ jag bought ]factory hoses
so just ordered new stainless steel ones
back to the start again
ro