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Brake booster push rod adjustment question

dan juhasz

FBBO Gold Member
FBBO Gold Member
Local time
7:50 AM
Aug 5, 2016
Reaction score
Whiting NJ
I took my 67 Hemi GTX for a first shakedown run today. Had trouble with all the wheels dragging a little once heated up. One wheel more than the rest but that caliper needs to be replaced ( bendix 4 piston). Booster was rebuilt by booster steve, master cylinder is new ,all hydraulic hoses are new, as are rear wheel cylinders. My first question is how to measure to make sure the booster rod setting is correct. If the master cylinder piston is held flush to the base and a depth measurement is taken and also measured the push rod at rest, what is a correct gap if any to be left? I would think too much might be as bad as not enough in terms of allowing fluid to return ( piston in a neutral position) to the master.
Second question could the proportioning valve if sticking cause fluid not to return to the master.
Did you try putting your toe under the brake pedal and pulling up Dan, sometimes that's all it takes to diagnosis that the rod needs to be shortened slightly.
On my way home slowly to avoid using the brakes as much as possible I kept reaching under the pedal to try and pull it up. To no avail, when I got home and on the lift both the disc and drum had serious drag to rotate. I cracked the bleeders in the front and it did help some. As it cools quickly they get easier to spin. So I’m thinking the adjustment is wrong or I’ve got a problem with the proportioning valve.
The booster rod should have around 5 thousands clearance to the master cylinder piston.