Brake drag from new pads/rotors

Yesterday I did a pad/rotor swap with DBA T2 rotors and carbotech Bobcat's (1521). Went for a drive to bed them in, and there was brake fade way earlier than there should have been. There was also a lot of drag from the front wheels.

This morning, I pulled some fluid out (it was over the max line) and tried again. Same results. Rotor temperatures after some light braking were around 550 F, and after some cool down driving were still around 500-550 F.

I pulled the calipers again, filed down the backing plates on the pads where it looked to be rubbing, re-cleaned/greased everything, made sure the pads slid freely, and torqued the slide pin bolts to the proper spec (they were previously way over-torqued).

The result was slightly less drag, but still too much. I drove the same route as earlier and got the same 550F temperature before cooling down, but the after temperature was down to about 400 F.

Anyone have ideas as to why I have this drag? Are the pads just too thick? Any idea what a normal rotor temp is for a car this size? Any help appreciated.

Are your calipers able to move freely on your slide pins? If they’re binding, that could cause things a pad to jam against the rotor. I’d like to say it’s not common for the pins to get contaminated and corrode all at the same time, but it could happen and is relatively easy to check.

Next thing I can think of is whether all of your caliper pistons are moving freely. I’d imagine you would have noticed this, having to retract them when you replaced the pads, but it doesn’t hurt to double check.

After that, I suppose there could be something causing the master cylinder piston to bind in the bore, but I’d imagine you’d be having other problems as well. That’s not usually how master cylinders fail.

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Does it scrape more if you make a turn?

It could also be rust build up behind the rotor not allowing it to seat fully. Make sure it's clean and not too chewed up.

Are you torquing the lug nuts or just hitting it with a bunch of ugga duggas?

If you lift the front do the wheels spin without too much drag or have a tight spot?

Are your calipers able to move freely on your slide pins? If they’re binding, that could cause things a pad to jam against the rotor. I’d like to say it’s not common for the pins to get contaminated and corrode all at the same time, but it could happen and is relatively easy to check.

Right on. Turns out the pins getting corroded is somewhat common according to a local subaru guy that used to work at a dealer. I wasn't aware the pins were so easily removable - I thought they were more involved to disassemble and therefore didn't need lubed very often. According to him they should be lubed every time the caliper comes off. Theres also a rubber sleeve on the pin that can keep moisture in and start the corrosion.

Pins out and lubed, rubber sleeves removed, and it's back to normal. It must just be because the caliper is using its full travel that I just experienced it now.

Thanks!

If you lift the front do the wheels spin without too much drag or have a tight spot?

It was very tight all the way around. For reference, if I slowed to a crawl on a slight incline, the drag was enough to stop and hold the car still.

I measured the temps again after a similar drive to this morning, and front rotor temps were around 225 F.

Right on. Turns out the pins getting corroded is somewhat common according to a local subaru guy that used to work at a dealer. I wasn't aware the pins were so easily removable - I thought they were more involved to disassemble and therefore didn't need lubed very often. According to him they should be lubed every time the caliper comes off. Theres also a rubber sleeve on the pin that can keep moisture in and start the corrosion.

 

Pins out and lubed, rubber sleeves removed, and it's back to normal. It must just be because the caliper is using its full travel that I just experienced it now.

 

Thanks!

 

 

 

 

It was very tight all the way around. For reference, if I slowed to a crawl on a slight incline, the drag was enough to stop and hold the car still.

 

 

I measured the temps again after a similar drive to this morning, and front rotor temps were around 225 F.

That’s great news! Frankly, this is why I have a policy of taking apart, lubricating, and reassembling my brakes annually once my cars get over 75k on them. It helps scare off problems like this. I’ve had pins stick too many times causing a brake to get stupid hot and then not long after have the caliper go, presumedly because the heat fried the piston seals. It’s sucks enough where it’s worth the two hours every summer.

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Are your calipers able to move freely on your slide pins? If they’re binding, that could cause things a pad to jam against the rotor. I’d like to say it’s not common for the pins to get contaminated and corrode all at the same time, but it could happen and is relatively easy to check.

 

Next thing I can think of is whether all of your caliper pistons are moving freely. I’d imagine you would have noticed this, having to retract them when you replaced the pads, but it doesn’t hurt to double check.

 

After that, I suppose there could be something causing the master cylinder piston to bind in the bore, but I’d imagine you’d be having other problems as well. That’s not usually how master cylinders fail.

 

 

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I had a brake pad get jammed on the caliper. It was for sure holding my car back a bit. It was so hot near the tire, and smelled like burnt rubber/chemicals...