Brakes: 50 Champ Brake Build Up Pressure and Lock Wheels

[wdills]

I need some advice on the brakes on Dads 50 Champ. We had this problem earlier this year and replaced MC, Wheel cylinders and rubber hoses. We finally took the hill holder out, cleaned all the gunk out of the body of it and removed the ball cage so it was just an open chamber. We thought we had it fixed at this point and he drove the car around on several short trips, but none were more than about 8 miles.

Today Dad took a longer trip, but after about 10 miles the brakes started dragging. They never completely locked but they did build enough pressure to have the brake lights on and the pedal didn't have any free travel left in it. When he got home he felt the wheels and all were hot but the left front was the hottest.

After the car set for a few hours and cooled off, the brake lights went out and the pedal had the free travel back.

I have all the shoes adjusted where you can hear just a little drag when I spin the wheel by hand. After adjusting the shoes I adjusted the pedal to get about 1" of free travel.

Any ideas would be greatly appreciated.

Wayne

[41 Frank]

It sounds like there is insufficient brake pedal free play. In other words, there should be about 3/8ths" clearance, or free play, between the brake pedal push rod and the master cylinder. The rod is threaded and adjustable. Loosen the lock nut and shorten the push rod until there is the aforementioned clearance. Generally 3/8ths or so clearance at the rod gives somewhere close to an inch of free play at the pedal. Make the adjustment when the brakes are cooled off. Let us know if this solves your problem.

[DWBookout]

There is a by-pass port in the master cylinder that could be plugged or blocked. See illustration 93 on page 42 of the Shop Manual. It took me quite a lot of trial and error to discover this feature.

[wdills]

Looks like Frank wins the prize. I had it adjusted for about 1" of free travel at the pedal. When I got home, Dad had already adjusted it to 2 inches of free travel. I didn't try to adjust the pedal up any higher because it was now working properly. Maybe the next time I am under the car, I will try to adjust it to about 1.5" of free travel and see what that does.


Thanks for all the feedback.

[StudeRich]

You may have used the fixed length Push Rod that comes with most New Wagner M/C's. It is better to use the original Stude. adjustable one and the length is usually fine as is. This could be causing free travel adjustment problems.

[jackb]

...I think you're confusing "clutch" pedal free play and brake pedal play....the brake pedal can't use 1 inch....

[wdills]

We did re-use the original adjustable pushrod. Unfortunately I started adjusting it before I understood how the automatic adjusters work, so I lost the original setting.

jackb, I don't understand your comment. You say that the brake pedal can't use 1 inch of free travel. So should it have more or less? I assume it has to have more since the brakes started working properly once we adjusted the free travel to 2".

Thanks again
Wayne