Brake Help.

SO I'm havingsome trouble with the brakes and I bet you guys could help.

I have a 66 289 with 4 wheel power drum brakes.

A couple weeks ago both of the brake boosters went out. We replaced them and it worked well for a week or so.

One day, I get in and I only have about 1/2" of brake travel, and it took a lot of throttle to get the car to move. Well, I found out that the front left brake is nearly locking out.

Basically, over a day or two period, it builds pressure and doesn't release it. I now carry a little wrench with me so I can loosen the bleed valve to release the pressure when it locks out on me.

Both of the front boosters are new. The MC and power vacuum think is new. The drums have been turned, shoes replaced, springs replaced.

The line from the MC to the metering block was kinked, so we replaced it.

What do you guys think it might be. Would putting the brake shoes on backwards cause stuff like this to happen?

I'm really stumped and I'm not a big fan of laying upunder the car in random parking lots just to bleed the pressure.


THanks all

danny clemens said:

If the flexible brake hose between the brake line and the wheel cylinder gets kinked or collapses on the inside it can keep fluid from backing out of the wheel cylinder. This might be a good place to start checking.

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I knew I left something out. The hoses were also kinked so we replaced them as well.

65ShelbyClone said:

I think there's a mixup in the terminology here. The big "vacuum thing" that goes between the master cylinder and firewall is the booster. I think the boosters you're referring to are in fact the wheel cylinders.

Is your master cylinder a newer-style dual reservoir or original-style single reservoir? Have you checked to see if the shoes are actually backward? I don't think it would cause your problem, however.

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Ya, sorry. The brake BOOSTER is new. That wheels cylinders went out, and we replaced them.

The MC is an original style single reservoir. I haven't had time to check and see if the shoes are backwards. Hopefully I can look at it sometime today or tomorrow.

If it helps, when pressure builds up and can't be released, it holds pressure all the way up to the original junction block (or whatever the thing is called thatdistributes fluid to the 2 fronts and the back brakes)

Is it possible that a valve inside that thing is gummed up so it can only let fluid in, but not back out?