I need some help. My 66 Skylark with power drum brakes won't stop properly. The brake pedal is rock hard and only moves about 1.5". I have replaced the booster which the service manual said was the most likely problem, but nothing changed, except for my bank account! I have vacum to the booster, clevis rod is in the correct hole, where is the problem? The car does stop, but it takes a really firm push to make anything happen and it positively will not lock up the brakes. I can't let my wife drive it as I don't think she has the leg muscles to stop this thing. Any help will be gladly appreciated as I can't go out in traffic with it as it is. Thanks
Sorry but I cant help you. I have the same problem with my GS 350, disc brake front and rear. So I will watch this topic for any answers.
I spoke to the rebuilder of the power booster I bought and they said that i must have 28" of vacum to make the booster work. So, I'm now the proud owner of a vacum gauge and as soon as I get back from this trip we'll see if there's any truth to that. 28" sounds like a lot of vacum at idle for a 300cu in engine.
Yea, I will say on an auto ,I'VE NEVER SEEN IT THAT HIGH. NO WAY. When I do Auto A/C work I use a vac pump which pulls 28" - 29" vac. Most vac on standard built engines {i've seen} runs 18" {or so} . It can run much lower with a worn engine or a large cam. Just did this year a 4 wheel disc, power brake connersion. Built my engine in 1983 with a mild cam and have added other goodies over the years. It will stop on a dime. Check your vac and let us know the reading. Also what happened in the first place was the power failure gradual or did the car sit and when you want back out, there was no power ?
That guy is hauling a mile long freight train of Bullsh!L. Mine work just fine on 15 inches of vacuum.
Well the saga continues: Wheel locked up and I couldn't get it off until this Sunday. Wheel cylinder leaking and hardware not in the best of condition, especially the adjustment wheel. I would like to buy the complete hardware kit, but it looks like only OPG carries it. With the shipping and handling charges of about 30%, I think I parts/pieces it at NAPA and Autozone. I have set the timing and dwell on the engine, still 13" of vaccum. I will now go through the brakes and see tf that affects the power brakes. the car has had this rock hard pedal since I bought it in December 06. More data as I stumble across it!
Double check the booster and the rubber vacuum hose,check for cracks or leaks. Check your brake pedal linkage for something preventing correct operation. I'm thinking you could have a stuck/corroded caliper or bent/kinked/crushed brake lines. 70 % of your braking comes from the front brakes,so start there first.
This could be the whole problem, If any wheel cylinder cups are siezed up this would cause poor brake power.
