Topic: Brake pressure

[DSO 90]

Hi friends,

I have a brake problem with my 68 Mustang, it brakes more on the rear than front axle ?!
and I can't jam on the brakes.

Do you have ideas ?
or
Do you know pressure values in the front and rear brake lines ?


Thank You !

Franck

[Rat Fink]

Sounds like the equalizing piston in your master cylinder is not centered.

[DSO 90]

In fact, I already did a test with another master cylinder
and I changed the original pressure differential valve near of it.
But the problem continue after the bleed of the brake system.

[Rat Fink]

I would say if you did check with another master cylinder, Then you don't have a problem. OOOOOORRRRR maybe you didn't check. Cause the probelm is in the master cylinder, the piston is not centered and all the pressure is going to the back. I can't figure out what""" I changed the original pressure differential valve near of it. """" means,,,,I'm Done.

[DSO 90]

OK, thank You Rat Fink !

I continue my research in this way.

[Jeff73Mach1]

If this has always been a problem since acquiring the car, I would start by verifying that the brake lines are not swapped and that the residual pressure valve is in place to the rear brakes in the proportioning block.  If the car has been upgraded to rear disks, then it needs a proportioning valve to properly regulate the pressures.

My bet is air in the front brake lines.

[DSO 90]

I know that car since many years. I gone in holidays for one month, when I come back at home, the problem is appeared.

The rear axle is mounted with drums brake. I also removed my front brake calipers for check if they're binded, but nothing.

I will check the proportioning valve.

Thank You

[ouch1]

souds like it is time for a proportioning valve.
http://www.mustangsplus.com/xcart/1965-73-Manual-Proportioning-Valve.html
I put one of these in my car when I did my disc brake conversion, and it works quite well.

-ouch1

[Jeff73Mach1]

I would suggest you disassemble your rear brakes, you have something wrong back there I suspect.  If the rear shoes are more than 5 years old they can look perfect and fall right off the backing plates due to the glue failing.