My 72 Newport has very sensitive brakes, they feel like they are going to throw you through the windshield, but the car is hardly stopping. And when it rains, the brakes tend to lock up!
I have slid into an intersection once, and nearly hit someone twice! Its scared the crap out of me. Maybe the rear drums aren't doing anything? Because it just feels like stopping a train in dry weather.
Any suggestions from someone more experienced than me?
There are several things that could be causing this:
1.) Be sure that both front and rear brakes on the split system are properly bled.
2.) Check the rear brake adjusters for proper adjustment, if this is a drum brake application, also check the front brake adjustment.
3.) Check the rear brake shoes for contamination from oil or brake fluid.
4.) If that does not solve the problem, check the travel rod adjustment for the master cylinder.
5.) Press down on the brake pedal firmly, Does the pedal sink? If so you have an internal leak in the master cylinder and it needs to be replaced. Could also have a leak at one or more wheel cylinders. Holding down the pedal will cause brake fluid to drip from out of the bottom of the brake drum. If any wheel cylinder fails this test, replace them all and replace all rubber hoses while you are at it.
6.) Are you hearing any hissing when you hold down the brake pedal? If so, your booster is probably shot.
7.) If the booster makes a hissing sound all the time, your check valve is probably shot.
8.) If the brake pedal feels abnormally "hard", the vacuum line from the manifold may have collapsed internally and is starving the booster for operating vacuum. This condition is often intermittent, it will vary with engine operating conditions, if you have an erratic feel to the pedal, that is your likely problem.
Dave
