I replaced my rotors and pads yesterday with powerslot slotted rotors and hawk HPS? pads. This is on an 89 GXL with 4 piston front calipers. Before I replaced the pads and rotors the pedal felt nice and stiff. Now after doing this the pedal feels quite spongy and travels much further than it used to. The ebrake also is not as stiff. The pads I replaced weren't even worn to the half way point. I did not open any lines, I did not replace or bleed the brakes after doing this because I plan to do that soon when I put on the stainless braided brake lines. I'm not sure I wore in the pads properly, I did quite a few 40-0mph hard stops. The ebrake got slightly better, but not as good as it used to be, the feel of the pedal is still spongy. Any ideas? I don't see how changing the pads and rotors would cause this to happen. The brake fluid reservoir is full.

 

Bleed the brakes, check the color of your fluid if its dark brown do a flush and refill it with new fluid, also if you are going to flush, but the lines on.



I have just brembo solid rotors, hawk HPS pads and cork sport SS lines, you barely push on my pedal you will eat the steering wheel.....

 

Yeah, mine used to be a lot more sensitive, but just after the replacement of pads and rotors it got way worse, I just didn't think that could happen. I will see if I can find time today to do this...

 

I have found that it will take a little while for new pads to wear to a point where they will "feel" right, but if you've already broken them in then that probably isn't the problem. Bleed the brakes. See if that fixes it.

 

Okay, today I put in the new stainless steel lines, new fluid, and bled it. Pedal still feels the same as before, soft. I can lock them up, but the pedal just isn't as stiff as it was. I felt a lot better before I put new pads and rotors on. I don't get what would have caused this. If I had used cheap pads maybe that could be it, but they are Hawk HPS.

 

A worn out master cylinder can cause that. Fluid leaks past the seals, preventing pressure from building as fast as it should.

 

I don't think it would be the master, because it was perfectly fine before I switched the pads and rotors (without touching the lines).

 

Pressing the pistons back into the caliper to change pads can be just enough sometimes.



But theres other things it could be too, maybe an air bubble somewhere you missed, a fitting thats not quite tight enough, etc.

 

perhaps issues with the pistons on your calipers..

 

An excellent point! I have often had problems with dragging calipers, especially on older cars, right after changing pads. You push the piston back in to accommodate the new pads, and it never works the same again. You could take the car for a drive, being careful to use the brakes as little as possible. Roll to a stop and get out and put your hands on the brakes (carefully!). If they're particularly hot, I would rebuild the calipers.



Typically, I've only had one side fail at a time, which makes it easier to diagnose, since the hot brake will grab less than the cool brake and cause the vehicle to pull to one side whilst braking.