help! 79 with almost no brakes!
Thread Starter
Instructor
Joined: May 2011
Posts: 135
Likes: 0
From: Horicon Wisconsin
help! 79 with almost no brakes!
So I pulled the motor this spring and rebuilt it and replaced all of the top end. The motor now has the summit 600 carb on top and I have the brake vacuum line attached to the back of it. When the car is off the brake pedal has good firmness to it. But when the car is running and in gear the pedal is very soft and brakes seem nonexistent. The brakes worked just fine before the motor was pulled so nothing was touched on them. What could have caused this?
Melting Slicks
Joined: Feb 2006
Posts: 2,092
Likes: 5
From: Fayetteville Arkansas
Sad fact is when the calipers with the older style lip seals sit they can leak and when they leak, air can get in the system. Start with diagnosing at the beginning of the system. Check the master cylinder by making sure it is filled. Then clamp off the soft hoses at all four calipers. With engine running and a good master cylinder, the brake pedal should be hard as a rock. If it's not, the master has a leak and needs to be bled or is going bad and failing. If hard, proceed by unclamping one caliper hose at a time and checking for the firmness of the pedal. The leaky caliper will show up when the pedal goes to the floor again.
hth,
Sully
hth,
Sully
Melting Slicks
Joined: Apr 1999
Posts: 2,010
Likes: 3
From: Moon Twp. PA USA
Sad fact is when the calipers with the older style lip seals sit they can leak and when they leak, air can get in the system. Start with diagnosing at the beginning of the system. Check the master cylinder by making sure it is filled. Then clamp off the soft hoses at all four calipers. With engine running and a good master cylinder, the brake pedal should be hard as a rock. If it's not, the master has a leak and needs to be bled or is going bad and failing. If hard, proceed by unclamping one caliper hose at a time and checking for the firmness of the pedal. The leaky caliper will show up when the pedal goes to the floor again.
hth,
Sully
hth,
Sully
