My booster was bad, I could hear the vacuum leak when I applied the brakes so I bought a new one from Then and Now Automotive. I put it on and when I went to test the car, I no longer hear any leak, but the pedal is still kind of high and hard. The check valve is the brand new one that came with the booster (which looks great on the car). Any ideas as to what else I can check?
First thing I would probably do is put a vacuum gauge on the hose going to the check valve and see what kind of reading your getting to the booster. Let us know what it reads
There is 25+ vacuum at the booster. When I disconnected the check valve you could hear the vacuum release so it is tight. Question: the brake pedal has 2 holes in it for the connection to the brake rod. Is it the bottom or top hole that should be used???
Well, if you have 15 inches of vacuum at the engine, you could'nt have any more than that at the hose to the booster. I just wanted to make sure there wasnt some sort of a restriction or clog to the booster that would explain a hard pedal. Bottom hole is for power brakes, top one is for manual.
My swap meet vacuum gauge must be junk! I checked all the brake hoses and they're fairly new and have no kinks. The brake pedal also seemed high so I disconnected the bracket from the brake pedal and turned the threaded rod on the new booster in about 1/4" and now the pedal is lower 1/4" and the brakes are a lot better. I'm thinking that must have been a factor. This is the 1st time I've had the car out this winter after putting on the new booster so maybe I'm so used to modern brakes on my daily driver I'm expecting too much. Jason, thanks for your help. Paul
Because of the weather I wasn't able to thoroughly test the car and have notice the brakes are better but I can't really get them to lock up when I simulate a panic stop. What can I look for for that? I put a new master cylinder in about 7 years (10,000 miles) ago and there are no pinched hoses or leaks anywhere. Thanks for any tips, Paul
How long since the drums/rotors have been resurfaced w/new shoes/pads? Glazed, or what I call "non-receptive" rotors or drums will cause this.
IMPORTANT POST. I scratched my head 1000 times on this one. I could not get ample brake pressure at the front calipers on my 1970 GS 455. My Brakes were worse than manual non power brakes. I swapped out the master cylinder, booster re did all the lines, new calipers and rotors and nothing worked. What I finally discovered is that the Banjo bolts were too long and were pinching pressure to the caliper. It turns out that when the remanufactures of calipers rebuild the cores, they face off and clean up where the banjo bolt face is located. This changes the depth of the bolt and can pinch off the pressure. I hope this helps somebody else chasing down this issue.
