Brake pad/rotor replacement


#1

I recently changed the front pads and rotors on my 1998 V70. Now the brake response is slightly different. The car will stop OK, but it seems the decceleration from 10mph to 0 is longer than it used to be or requires more force than before. I’ve read about brake fade and “bedding in” on new brakes brakes but this car (which has 200k miles on it) has had pad/rotors installed before without this issue. The brakes seem to be safe, I just would like to know if the braking performance will improve as they bed in together or is there something I could have done wrong. I did let some brake fluid out of the bleeder to get the piston retracted but did a minor bleed afterward to make sure there had been no air entrained. The brake pedal position doesn’t appear to be different and the brake is well off the floor when braking hard.



Any help would be appreciated


#2

you probably got air in the bleeder.

also if you got cheap pads that could be the fade also.

actually in all honesty I would guess that if you touched the bleeder screw you got air in the system. you DONT have to touch the bleed screw at all, unless you have to change the caliper itself.

it only takes a couple of bubbles of air in there to make it mushy. i know you did a ‘minor bleed’, did you use a bottle with two hoses and brake fluid in it hooked up to the bleed screw? this lets the fluid out, but ensuring that no air goes in? (or use a vacuum pump?)

if you jut cracked the bleeder, with no hoses on it, you got air in.

thats enough to make the mush on the last braking occur.


#3

What brand of brake pad and rotor did you use? For a car with 200K on the clock, I’m willing to bet you you did no go with OEM, but with an aftermarket set from the local parts store. Some of these do cause problems like your mentioning. I also do not like to use the Duralast brand at AutoZone. The last couple of times I used them, I was getting a funky vibration if I hit the brakes hard. Heard from other people that they had the same problem. Use a different brand, problem went away.


#4

There are a lot of things that can cause this. When you pushed the caliper pistons back in place, there may have been some rust or scale on the part of the piston that was past the cylinder seal and is now getting hung up on the seal. The caliper pins could be hanging up too but I don’t think that is part of the current problem. It could be in the caliper hardware, as the pads moved in due to wear, the parts they scraped on rusted and now the new pads are riding on the rusted area.

This could also be caused by the master cylinder, but if it occurred suddenly right after the brake change, then that is probably not it. It could be the pads, but that is usually a problem after several high speed stops, not just one. BTW, I have had good luck with Duralast.

When brakes start doing this, it can be difficult to find the answer. I have an 86 Toyota Tercel 4wd that is doing the same thing. I’ve tried 3 different set of pads, two rotors, replaced all hoses, rear wheel cylinders, drums and shoes as well as one new caliper on the front and rebuilt the other and put in a new master cylinder. Today I’m putting in the third master cylinder because the one I bought yesterday didn’t work. These have all been remanufactured master cylinders. If this one doesn’t work, I’m going to bite the bullet and buy a brand new one.


#5

Thanks for all the good comments. I did not do the proper bleed with the bleeder, I just let the fluid out when the piston was being pushed in, so it could well be air in the system. I’ll do the bleed. The pads were Mintex and rotors were ATE, so I they’re OEM-like (but were not strrict OEM).

Thanks again, I appreciate the input and hope you get your issue resolved.