69 Mach I Brakes - Hard pedal
#1
My brakes have been giving me trouble for the past year. This is driving me nuts, brakes aren't rocket science. Anyone have suggestions for these symptoms?

The brakes work Ok for about the first 1/2 to 3/4" of travel in the pedal. Then it feels as though the pedal hits the end of it's travel and I almost have to stand on the brakes to get the car to come to a stop. I have 15 inches of vacuum at the booster, a new master cylinder (a year ago) and a new booster. All of the brakes bleed Ok, so there doesn't appear to be anything clogging a line or the proportioning valve. The pedal doesn't fade at all - it's rock solid after that first 1/2 to 3/4" of travel.

Can anyone tell me what length push rod you use from the booster to the master cylinder? It came with two - a long one and a short one. I did lots of measuring last summer to determine the right adjustment for the rod and used the long one. I'm assuming that the MC end of the rod should just touch the piston in the master cylinder when the brake pedal is at rest. To that end, I measured the depth into the master cylinder to the piston and adjusted the rod so that it just touched the cylinder.

Any other suggestions of where to look?
Thanks,
Hutch

Some other updates ... I had an inspection mechanic buddy look at it today as well. He just called to say that he pulled drums off the back and verified that, with the car running and the drums off, the shoes expand out normally and the brake pedal has a full range of travel. When he puts the drums back on, the hard spot returns.

Likewise, when he takes the pads out of the front calipers (and inserts a piece of oak so that depressing the pedal doesn't blow out the seal in the caliper cylinders), the brakes seem to work flawlessly and the pedal has normal travel. When he reassembles the front brakes, the hard spot returns.

Reply


Messages In This Thread
69 Mach I Brakes - Hard pedal - by Must69ang - 04-14-2015, 10:37 AM
RE: 69 Mach I Brakes - Hard pedal - by 1969_Mach1 - 04-14-2015, 08:25 PM
RE: 69 Mach I Brakes - Hard pedal - by Must69ang - 04-15-2015, 02:48 AM
RE: 69 Mach I Brakes - Hard pedal - by 1969_Mach1 - 04-15-2015, 03:38 AM
RE: 69 Mach I Brakes - Hard pedal - by Must69ang - 04-15-2015, 08:31 AM

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