Brake Pipe Distribution and Switch

[Stephen L.]

Re: Update

Patrick, I believe you misunderstood me. In MY case the plunger was too long for the M/C resulting in the rubber cup inside the M/C not clearing the hole to the reservoir. This, in turn, would not allow adequate fluid to enter the bore, hindering proper operation when the pedal was depressed

In your case, you said the hole inside the metal plunger was not as deep as its predecessor. You don't need to drill out the plunger, you need to adjust the rod and clevis which is attached to the pedal to compensate for the "shallow" hole in the plunger. That is one reason the shaft is adjustable... to compensate for manufacturing tolerances of the entire assy.

Any time you change M/C's you should check for "free play" on the shaft to insure that the plunger is fully retracted with the pedal "at rest". All you need are a few thousands of an inch....

[Patrick H.]

Re: Update

Steve,

due to the fact that the hole was not deep enough, the MC was also "chronically depressed" like yours and the hole never opened up. It was the exact same issue. The pushrod that comes out of my Cutlass power brake booster is not adjustable for length, so if the hole in the MC is too shallow it then causes the MC piston to be pressed when you install the MC on the booster and fully tighten it down. I tried every conceivable way to try and adjust the pushrod, but didn't figure it out until I compared the hole in the new MC with the one in the old rotten MC I'd removed.

Patrick

[Stephen L.]

Re: Update

Patrick, I found this photo of a 70 Cutlass brake booster on the internet.
The adjustment rod is inside the car under the dash. Its the rod that passes thru the firewall. Check it out.

[Patrick H.]

Re: Update

Picture doesn't load.

I tried that. It did NOT make a difference.

And, since my 2nd replacement matched my crusty original and matched the other Delco one I inspected, I still found the best option to be finding a part that fit rather than dealing with one that was not made correctly.

Patrick