Packard Forum Index » Post-War (1946-54)

I'm having trouble with my '53 Junior's brakes. I replaced every brake component except the backing plates 2 months ago. Over 1000 miles of daily driving, I started to notice the driver front wheel grabbing during braking. It got progressively worse to the poing the wheel would lock up and I would have to slam the pedal to free the wheel.

I had my friend spin a wheel with the car on jacks while I pressed the brake. The wheel immediately locked up and did not release until the bleeder screw was opened.

I have heard every shadetree diagnosis from bad rubber lines to wheel cyls, to a blocked compensating port.

I replaced the wheel cyls for a second time, adjusted the brake pedal pushrod, checked rubber lines, re-bled the system, all to no avail.

Is this a common problem? What am I missing?

It sounds to me as if the compensator port in the master cylinder is not being uncovered when the piston is in its full release position. The previous owner of my 115C had a problem with the brakes not releasing. He discovered that the piston supplied with the master cylinder overhaul kit was the wrong one. It would not uncover the port when in full release. This is where I would look first. Good luck, and let us know what you find out. It may save someone else to avoid this problem.

G'day Millers1953,
to PackardInfo. Wish you well in tracking down and solving your brake problem.

If only one brake is locking up it is obvious the problem is with that wheel alone. Oil on the shoes and the surface of the drum is one thing that can cause the problem. A blocked oil line to that wheel although if it were completely blocked the brake on the wheel would not work at all. I had this problem with my 51 to start with. Found a blocked line when I went to bleed the system. A brake that is adjusted to loose can sometimes cause it to grab. Mostly it will be oil or brake fluid on the linings. Hope this helps.

JW, I can see that the compensating port in the master is not open. The master is brand new. I tried to use a Kanter rebuild kit with my old master but it never worked again.

ozstatman, thanks, I was a member on here before but lost my password and never got an email telling my my password...

Bob1951, three wheels are affected, driver front and both rear.

I suppose I need to get another master cylinder. Not what I was hoping for.

Is the piston rod from the brake linkage rod adjusted so that the there is enough free play and the piston is allowed to return completely? I had a similar problem but somewhat different problem after rebuilding the MC on my '47. I adjusted the rod which connects the brake pedal linkage to the M/C too fine and when the brake pedal was released the piston would not come back far enough to clear the compensator port and the brakes would partially lock and the brake lights would stay on. I am not sure with only one brake locking this would be the problem but if that wheel is adjusted with less clearance between shoes and drum than the other three wheels it might be a possibility.

I agree; adjust your pushrod so there is at least 1/4" free play at the pedal. If your compensator port is still blocked, poke it free with a wire, or if all else fails and it has somehow rusted shut, I have drilled them with a 1/16 bit right through the brake fluid.

And it's true, brakes adjusted too loose will sometimes grab violently when the shoes finally reach the drums.

Quote:
Looks like a job for BigKev, our Webmaster. Did you contact Kev for a replacement password? Probably too late now, but if it happens to you or anyone else for that matter, Kev's email address of bigkev@packardinfo.com is at the foot of each page on the Site. BTW, what was your earlier Forum Name?

I have had bad rubber brake lines that would only let fluid in and not back. rubber inside goes bad .

I vote for brake hose as well. If it was the master they would all , most likely, be locking up. I had an old Cadillac once that had the same problem, brake hoses can look good but inside they collapse and don't let pressure off when released. Good luck.