Brake pedal travel

[Skymarshal]

New brake system all around on this car- new master, lines, calipers, and wheel cylinders. The brake pedal now goes nearly to the floor before the brakes engage. I know it's not bottoming out because I can still lock 'em up, and I've bled the system over and over without getting any bubbles. The rear drum cylinders are adjusted properly.

Any ideas for how to get a more normal pedal? I filled the system with DOT 5 fluid which I know will cause a softer pedal, but it shouldn't make it as bad as it is now.

 

[tx65coupe]

Did you upgrade or change the master cylinder to something other than stock? If so, you may need a longer actuating or push rod.

 

[MustangB]

I agree with tx65coupe. Odds are you were mistakenly shipped the wrong length rod.

 

[DukeGnarley]

are you using a brake booster?

if so make sure the push rod inside of it is adjusted properly so that it almost makes contact with the MC.

 

[Skymarshal]

It's the correct MC (and it is new), and it has the stock brake booster. I didn't change the pushrod when I changed the MC. Is it adjustable without pulling the MC? Getting that thing mounted past the shock tower was a real bear.

 

[DukeGnarley]

you have to remove the MC to get to the push rod. Do you still have the old MC? make sure the hole is the same depth as the old one.

 

[2+2GT]

Did you set the headspace? IIRC, it should be 0-0.012.

 

[68RCodeConv]

This is a common problem with new rear brakes. If they are not adjusted tight the brake pedal will have a lot of travel. Jack up the rear tire and use a screwdriver to turn the star wheel until you get some drag as you spin the wheel. Press the brake pedal to center the shoes and adjust again. You only want light drag as you spin the tire.

 

[65fastbackresto]

Do you have a residual pressure valve?

WILWOOD RESIDUAL PRESSURE VALVES These in-line pressure valves retain a minimum brake line pressure to help eliminate excessive pedal travel in....

Read more at Wilwood Brakes

I have the 10lb one mounted below my mc in route to the rear brakes, it helped my pedal pressure quite a bit.

 

[chockostang]

New brake system all around on this car- new master, lines, calipers, and wheel cylinders. The brake pedal now goes nearly to the floor before the brakes engage. I know it's not bottoming out because I can still lock 'em up, and I've bled the system over and over without getting any bubbles. The rear drum cylinders are adjusted properly.

Any ideas for how to get a more normal pedal? I filled the system with DOT 5 fluid which I know will cause a softer pedal, but it shouldn't make it as bad as it is now.

If you used the MC36440 Maverick Duel bowl master, there is no residual built in this. The residual needs to be inline after the master on the rear drum system. Simple easy install. Of course, the Front bowl of the master is the rear circuit.

The Next cause is rear adjustment, I'd venture to say a least half, if not 75% of excessive pedal travel is improper adjustment.

If the rears are assembled correctly (Shoes on correct sides), the adjustment will be to turn the adjuster till you achieve full lock up on both sides. Then adjust back out till the shoes are barely draging on the drums.

Dan @ Chockostang