spqr

Hey guys,

I installed new pads and rotors on my 2011 v6. (I went with centric high carbon rotors and stop tech street pads). Install seemed to go well, but I noticed a slight drag. I can spin the wheels, but they dont spin very much, and I've noticed a stick when the car rolls to a stop (if stopping on an incline, it'll stick instead of start rolling backwards). Is this normal?

Attempts to fix the issue:
lubed slid pins (forgot to do it the first time) - no effect
flushed brake system with new fluid - no effect
attempted bed in procedure (2 sets of 10 hard stops) - got rid of most of the drag, but not all of it

Should I try another set of bed in? Should I wait to see if it goes away? Is there something else I should check?

5.M0NSTER

When you change your pads and rotors/pads, with wheels off they ahould be able to spin once or twice before they stop. That's pretty normal.

As for the drag, do you have drag when coasting in neutral at low speed, or does it seem pretty free flowing? If you didn't push the cylinders back enough when changing pads it may contribute to pads dragging.

As for the hill, our cars have a Hills Start Assist which holds brake pressure on a grade for ~3-4 seconds when you remove your foot from the brake to give you time to get the car in gear. Are you sure that's not it?

spqr

Last i checked, it was closer to 1/4 - 1/2 turn while in the air.

I've noticed the drag in neutral and gear. There's a hill on my commute that if i coasted down in top gear at 60mph I would stay at 60 or accelerate slightly. I now end around 55. I've also noticed a drop in fuel eco (1-2 mpg).

I know that I pushed the pistons in far enough because i can feel the slack in the brake pedal when I pump it back up. I also redid both front brakes (where it occured) to double check it.

I don't believe mine has a hill start assist. I've driven my buddies bimmer a few times so I'm familiar with it, but I've never noticed it on mine before. I can let off indefinitely and it won't roll on a slight grade anymore.

5.M0NSTER

Hmm, the only other thing I can think of is the backing plates. Did you re-install the thin, metal backing plates? Some aftermarket pads are not meant to be used with them.

I don't use backing plates when I switch to my race pads before track weekends.

But I've changes the front brakes on my car a number of times, and noticed the rotor spins pretty freely. If it doesn't, I push the pistons back in more, and gauge if they are back far enough by the amount of clearance I have between the new pads and the rotor. On first pedal apply after that the pedal usually goes to the floor.

LEXiiON

Did you do rear pads? Most of the time, the little pin on the rear pads is not inside the caliper hole, causing the rear pads to stick out to far and creating the drag.
When the rear caliper is completely retracted, the two holes for the pad pins need to be vertical to fit the pin in. If they are not vertical, the rear pad will cause the drag. It is the inner one. You can easily see this, if you look on the inside rear disk and only see a small fraction actually been used by the pad...

LEXiiON

spqr

The new pads came with backing plates, so I kept them on. I had to replace an anti-rattle clip as one broke, but otherwise left the stuff stock. When I pull the calipers off, the pads spring away pretty quickly and easily so there's clearance around the ears and they seem to be pretty well lubed.

I'm worried that maybe i introduced other issues when i flushed (like some residual air?). Is it ok to leave the parking brake on? Do you bleed the caliper when you push the piston in? (ericthecarguy mentions that it can sometimes damage the master/slave).

spqr

Yes, I did the rears as well. I think I remember setting the two holes to vertical. I think the first attempt I didnt and there wasn't enough clearance to get the caliper back on.

LEXiiON

Double check the rears. Also try to pin down the drag. Jack each wheel up and see which ones do no spin freely. That narrows it down.

LEXiiON

dmichaels

Is the Parking brake too tight? I recently adjusted mine cause my rear caliper was dragging. I have a few other braking issues that I've been sorting out but adjusting the parking brake helped a bit

spqr

I'm going to double check the rears tomorrow. I haven't looked into checking the parking brake; the pressure on the handle feels the same as it did before. Would it feel different if it needed adjustment?

dmichaels

If it was too tight, you probably would feel it, but in my opinion, it's worth loosening a couple turns (really easy to do) just to eliminate that as a possibility.

spqr

Regreased the rears. There is definitely more drag than the fronts, but i'm not sure how much is drivetrain and how much is brakes. My FIL knows much more about cars than i do and he thought it was fine.

The front right seemed to be dragging more than the left and there was a slight squeal when turning it. I pulled that one and cleaned off the anti-rattle clips and regreased them lightly (i think i put too much grease on the first time; lots of dust in there). I also sanded the ears a very slightly as there was a little bit of stick when i was testing to make sure that they pushed away from the rotor.

Also, i forgot to mention that one of the springs on a pad came bent from teh factory, but i didnt notice until too late to return them. I bent it back to shape before installing and it seems to push away from the rotor as easily as it's mate so I don't think that's the issue.

I haven't checked the parking brake yet.

Big Poppa

Fold down the back seat and have someone get in the back and listen for anything unusual or you get back there and listen while someone else drives. That's how I nailed down a bad caliper issue I was having.

spqr

I think I fixed it. The initial issue seemed to be that I just needed to bed the pads properly. However, the first time I bled the brakes, I think I went too quickly. I redid it and found a few air bubbles. Things seem to be back to normal.