[Z28Hans]

Hi all, I have a front disc, rear drum set up on my Camaro 67, I think the last owner did a bad conversion, i just bough a 69 Camaro master sylinder, since my old one was leaking, I thought that was the reason why I didnt have any front brakes, but it didnt help,

to the point, im wondering if the last owner have connected some stuff wrong, when i bleed my rear brakes, the front chamber on the master cyl gets a lower level, does that matter? is the pump different on the front and rear chamber? whats normal.

my calipers are in good condition, they are one piston, i bought new pistons and seals for them, I found it difficult to bleed the front brakes, fluid comes out, but very slow, compared to the rear.

[davidpozzi]

Hans, Welcome to Team Camaro! [img]graemlins/beers.gif[/img]
The front outlet on the master cylinder should go to the front brakes on a stock Camaro.
Many Ford master cylinders are the reverse of that. The connections do not matter except the larger reservoir should go to the front brakes. The front brakes require more fluid as the pads wear. When new pads are installed, the caliper pistons are pushed back in, and the fluid returns to the reservoir. If the reservoir is too large or too full, the fluid will spill out of the reservoir.

On my street vehicles I do not add brake fluid as the pads wear, when I install new pads, the fluid level returns to full.

Remove the bleeder screws and clean them, they can restrict flow.
If you do not have easier bleeding after that, check your brake lines for dents or restrictions and change your brake hoses. The hoses can go bad inside.
David

[Z28Hans]

Thanks, good tips there, im gonna check the lines, both front brakes are just as bad, so it must be the line to the metering valve if that what it is called, on my car the rear brakes go in to the metering valve to? thought they werent supposed to do that on a disc fron drum rear car, and i dont have the 10lb residual valve yet, i have to get that, but that wont solve the front brake issue? Is there supposed to be a rubber seal one the master syl against the booster? its leaking there, i made one that works

[bretcopsey]

Hans, you may have answered your own question! You said the master cylinder is leaking between the back of the master and the booster? That is a sure sign the master cylinder is bad and needs to be replaced. There is no seal there.

[davidpozzi]

There is no seal to the booster. Do not make one, there is a vent hole from the bottom of the rear of the master cyl bore that intersects a cross hole in the bottom of the master cyl, that hole will drain out any brake fluid that leaks. If you install a seal between booster and master cyl, the fluid will build up and go into the booster and damage it.

It sounds like you have a later all-in-one "combination valve", this valve connects to both of the master cyl outlets.
You don't need a 10 lb residual pressure valve, many later systems aparantly did not use one. If needed, it would be in the rear circut only.
The residual valve was used to keep the drum wheel cylinder seals against the bore. If the pressure went to zero, the seals would leak. I guess the later designs did not need this residual pressure.
The change from residual to no residual valve is not clear but happened sometime around the late 60's early 70's.
I took apart a 69 disc brake master cylinder and it had no residual valve, but one person told me it was in the distirbution block/ brake light warning switch.

Master cylinders can also leak internally.
David