Power Disc Brakes not working on hard stop?

360notch said
Just a data point. I have had a 67 barracuda 360 4-speed with manual stock KH discs and stock 8 3/4 drums. Stopping was good from all speeds.

Question, because I don't know the answer: If you disconnect and plug the vacuum line, can the brakes be worse than manual? If not, you could try that and see if the high speed stopping problem is still there. Based on my good experience with manual disc front brakes, your leg force should be more than enough.

OK based on discussion and your success without power brakes, I've, disconnected the brake pushrod - Pedal to Booster and travel of pedal is much greater than when connected - so not pedal. So given everything else the limit has to be between power booster and MC. Life is short and I need to resolve this - I ordered a new booster set up from Summit so I'm hoping that eliminates any issue between input to booster to output of MC. Will let folks know result of this experiment. Unfortunately I live in Minnesota and will have to wait until spring to really test but I'm hoping to get a different pedal feel. Will advise!

Johnny Dart said
I'm kind of going through the same issue. Took the 70 Dart out today, and wasn't happy with the stopping power at high speed. Small bolt, manual Kelsey Hayes brakes, 14" wheels. My plan of attack will be to scuff/clean the front rotors, and find the latest, greatest front pads. Then take off the rear wheels, and scuff the shoes and drums, and reinstall/adjust.

Somebody mentioned to you about glazed pads/rotors, and you looked right past it. Could be your problem. News pads, and a normal brake service.

Sorry, no the brake pads are not glazed - apologize I didn't;'t mean to blow past it