disc brakes & master cylinder problem

[Dwight]

My friend has a Cobra with Lincoln rear 11" disc, Mustang front disc and two 3/4" master cylinders. The problem is weak brakes that improve if pumped several times. After we bled the brakes, With the brakes applied, I could turn the rear rotor. I think he needs a larger master cylinder for the rear and adjust the balance bar. What do you think?

Dwight

[mj_duell]

Originally Posted by Dwight

My friend has a Cobra with Lincoln rear 11" disc, Mustang front disc and two 3/4" master cylinders. The problem is weak brakes that improve if pumped several times. After we bled the brakes, With the brakes applied, I could turn the rear rotor. I think he needs a larger master cylinder for the rear and adjust the balance bar. What do you think?

Dwight

That is true, the larger cylinder I mean. I used a 1 inch front and 7/8 rear on my A&C.

--Mike

[Richard Hudgins]

Originally Posted by Dwight

My friend has a Cobra with Lincoln rear 11" disc, Mustang front disc and two 3/4" master cylinders. The problem is weak brakes that improve if pumped several times. After we bled the brakes, With the brakes applied, I could turn the rear rotor. I think he needs a larger master cylinder for the rear and adjust the balance bar. What do you think?

Dwight

You need to smaller on the rear MC, not larger.

[trularin]

I had the same setup...exactly. Mustang II fronts and Lincoln rears. I have to put 7/8" master for the rear and 3/4" for the fronts. Then I adjusted the balance bar from there.

The Lincoln has a large surface area and work well...once the system is balanced.

Just my $0.02

Dang, maybe it was the other way around.

[Clois Harlan]

I have tried it several ways including the way some of you have mentioned. Richard is right, go smaller on your rear Master Cylinder. I used a 3/4" rear and a 7/8" front. I am running Wilwoods in the front and Explorer rear calipers.

Oh yes, Keep bleeding because you still have air in your lines (check all your connections again).

Clois

[undy]

I run a 5/8" front brake master cylinder, but I don't think M/C size is your problem. It's an improperly adjusted balance bar. Before you start juggling master cylinder sizes adjust the balance bar for more rear brake bias. Tilton has a real good set of instructions on their web site. All this is assuming that both systems have been been bled properly and your rear circuit is not air-bound.

I'm getting ready to do a Wilwood 12.19" 4 piston conversion on my fronts. I'm currently running Exploder 11" rear rotors/calipers and my fronts are GM metric calipers on Mustang II spindles/11" rotors. The 5/8" M/C gave me the front brake stopping power I needed. I may need to go with a larger front M/C with the Wilwoods.

Dave