Another question I have is about the brakes on the car. Keep in mind this is not my car and I have no clue how the brakes were before I started working on them.

The car has an aftermarket 4 wheel disk system installed. I have rebuilt all 4 calipers because they were leaking. I only got about 1/2 - 3/4 pedal on the first push. I then replaced the master cylinder. System is bled properly and still only get about 3/4 pedal. The lines are not bulging and there are no leaks.

My question is as follows. With a stock master cylinder, is there enough fluid transfer to move what in all actuality is 16 pistons on the first press of the brake pedal to have a "hard" pedal. The guy that owns the car says that he thinks the car had a hard brake pedal before he parked it, but that was over 5 years ago. Or is a "softer" pedal normal for the disk upgrades? Also, there is no brake booster in the system.

Thanks again,

John

 

I only got about 1/2 - 3/4 pedal on the first push. I then replaced the master cylinder. System is bled properly and still only get about 3/4 pedal.

Are you referring to range of motion/travel of the assembly or actual distance?

With a stock master cylinder, is there enough fluid transfer to move what in all actuality is 16 pistons on the first press of the brake pedal to have a "hard" pedal.

You mean the first time you press the pedal after everything is rebuilt fresh I hope...... I'd be surprised, but if you have new pads, rotors, etc, the pistons don't have to move that much.......

 

When I say 3/4 pedal, I have little resistance on the first 1/4 of the travel. Then the pedal gets firm and hard at about 1/2 travel. I'm gauging travel to the distance the pedal pushed as we were bleeding the system when the pedal went to the floor.

The rotors are good and the pads have little wear.

The car has decent to good braking, it just takes what I consider quite a bit of pedal travel to get the braking action to work.

When we drive it, it almost seems like a need to pump the brakes to get a hard pedal. The first press of the pedal feels softer than I think it should be, but if you let off and push again, then the pedal feels good and the brakes work right now.

 

Pedal should be hard and not travel more than a couple of inches. You probably still have air in the system and/or the brake hoses need replaced. Did you bleed both halves of the rear calipers?

 

Both halves of the rear caliper? I only saw 1 bleeder and don't recall any other bleeders when I rebuilt them. I will go look closer at them. Also putting new hoses on as well.

 

Look on the inward side. Bill.

 

Were the rotors replaced also? You might be having rotor run out.

 

Found the inside bleeder. Very little if any air. The odd part about the rear brakes is that while bleeding very little fluid came out. I watched the resivour of the master cylinder while the brake pedal is slowly pushed and most of the fluid is just coming back into the back half of the resivour. I am replacing the "new" master cylinder again tonight. I am confident that this will fix the "soft" pedal.