Brake pedal travels too far

[cbaum111]

I have a 1939 Ford Coupe. I had a very capable mechanic replace the master cylinder, He is no longer available to fix the problem. He bled the system then he delivered the car I noticed the brake pedal would travel almost to the floor and then one pump and it was as high and hard as designed. I have to do this every time. I live on top of a mountain, descending the mountain is very interesting without brakes, I have done it in my model A. Could it be as simple as an adjustment?

[glennpm]

Seems like you have a leak or air in the system. Look all the wheels and brake tubing connections for leaking and collapsed old hoses, then bleed the system starting with the point furthest away; which is either of the rears for the Ford, then right front and finally left front. I would look at the master cylinder connection first.


Glenn

[Kube]

As Glenn has correctly advised, most likely air in the system or perhaps a defective master cylinder.
A defective cylinder is not as uncommon as many of us would care to believe.
Only a few months ago I had experienced a similar issue only to find the new cylinder was the culprit.

[joe 1950]

also check brake shoe adjustment maybe the shoes need to be closer to the drum

[glennpm]

Originally Posted by joe 1950

also check brake shoe adjustment maybe the shoes need to be closer to the drum

If this was the case, the pedal wouldn't rise with pumping.


Glenn

[deuce_roadster]

Sponsored Links (Register now to hide all advertisements)

We all need a sign above our workbench that says "NEW does not equal GOOD".
Trouble shooting by replacing things in today's world is harking back to a previous time, maybe 50 years. Try to test everything prior to installing. My 2 cents.

[cadillac512]

If the problem were air, the pedal would never be "hard" with one extra pump. It is likely brake shoe adjustment or the replacement master cylinder has too small a bore. (Or you have a lot of pedal travel before the master cylinder starts to move).

[40cpe]

I agree with cadillac. It takes all the fluid from the first pump to push the shoes against the drum because the mis-adjustment requires the cylinder to extend more. The second pump restores the pedal height. If it didn't do this before the master change, it could be that the master is undersized.

[FlatheadTed]

I agree with Cadillac also , if you pull the hand brake on and the pedal sets higher with one pump then its a adjustment problem.But likely a bit of both .Adjustment rod or mismatched MC or Air .

[Kurt in NJ]

What was the original problem?

[Flathead Fever]

I was a fleet mechanic for 30-years. This sounds like one of the problems I would encounter, the first push of the brake pedal moves the shoes outward and a rapid second push of the pedal pins them up against the drums giving you a rock-hard pedal, just like what you're describing. If your pedal is "hard" on the second push like you say, the problem is the shoes are adjusted to far out. That's if all the parts have the original size bores as the originals.

[Terry,OH]

Suggest before you bleed the brakes adjust the upper cams so all the brake shoes have a heavy drag. Then bleed and adjust cams for light drag after bleeding.

[richard crow]

flathead fever has it right

[glennpm]

Looks like we're talking to ourselves

[Clem Clement]

I used to be surprised after finding an old part under a workbench or a flea market pile, cleaning it up and finding it did not function. Seemed to me after rusting and dusting for many years, it should have fixed itself. I learnt there was a reason it had been removed from service...

I found a train set where the cars were very nice and the loco was rusted. Turned out the father had put the loco in the barn as it "don't run." I fixed a loose screw and have a great story.