01-18-10, 04:49 PM
Hey guys, I posted a little about this in my intro but wanted to see if I could get some more help. I have a 68 Coupe Deville (Drum Brakes) that is having brake problems. At first, the brakes felt fine other than the pedal would not return. So I replaced the Master cylinder and bled the system. Now, the pedal still does not return but the brakes feel a lot worse. As I push down the pedal it feels like it travels much farther than it should before the brakes start to engage and when they do engage they feel really hard, like they almost lock up. Does it sound like the power booster is bad? I would hate to spend $100 to buy a new booster only to find out that wasn't the problem. Any ideas?
01-18-10, 06:28 PM
I would say bleed the breaks more. I'm no expert but it sounds like air in the system and bleeding the breaks is free and easy so might as well try that first. I know you already bled them but sometimes these old break systems take a few tries
I agree, it sounds like you still have air in the brake lines. Remember to always start with the wheel farthest from the m/c. Also, if your brake pedal stays hard to push and still dosen't return when you let up, then I would bet that your booster is bad. I also had the same issue with my '68 some time ago. Good Luck!
01-19-10, 12:51 PM
Thanks guys, let me make sure I am correct, I would start at the Passenger rear wheel and then go to the drivers rear, then passenger front and then drivers front?
01-19-10, 06:12 PM
Hi from the UK.
I had the same problem with my 69, on mine i was using all my brake pedal travel just to get the rear shoes to touch the drums. i adjusted the star wheel until the shoes were just touching the drums, dont back them off like it says in the manual, this worked, no more excessive pedal travel.
also forget the auto adjusters, thay just dont work.
As for bleeding them manually, what a nightmare, on the first attempt i bled 8 litres through and still no pedal, in the end i took it to a garage and they used a pressure bleeder.
01-21-10, 12:22 PM
good call on the pressure bleeder, my brother has one. I would just need to get the adapter for the GM Master cylinder. Garys, so did you have to replace your booster?
Yes, I replaced the m/c and booster at the same time. The booster appeared to be original and I figured forty years of service was pretty good.
I think you can still get one at Kragen or Pep Boys for about 100 bucks.
Though I wouldn't stop there, I would rebuild (easy) the wheel cylinders and install a new brake hardware kit. (springs, keepers, etc.) Check out Kanter.com. These items are all fairly cheap. It won't ever stop like a car with disc brakes, but it will be pretty good. Good luck!!!