Lightly Dragging Front Brake 3.0

[tomgabriele]

I have done a bunch of research, and have done all the troubleshooting I can think of, but would like to ask for some more help. I recently replaced pads and rotors (Duralast Gold DG840 pads, Raybestos 980001R rotors) on the front. The driver's side is working perfectly. The passenger side drags lightly - I can't feel it while driving, but the wheel feels noticeable warmer after driving, and I boiled some brake grease and got a little smoke after driving ~1 hr on back roads. Lifting the front, the wheel can still be spun by hand relatively easily, but with noticeable resistance. The pads are clearly in contact with the rotor - the contact seems to be equal on the inner and outer pad too. Here's everything I have done/checked:

- Wire brushed and re-greased the caliper pins; they seemed to be in good condition
- Cleaned caliper bracket with wire wheel where the pads slide (there was some rust) and re-greased
- The caliper piston still retracts smoothly with a c-clamp
- The brake lines seem to all be in good condition
- No pressure buildup when opening the bleeder when the brakes are hot
- No other brakes have symptoms
- The rubbing is uniform as I spin the wheel
- I don't know when the fluid was last changed, but it looks fine when bleeding
- When driving, braking is smooth without any pulling

Does smooth retraction of the caliper piston necessarily mean that the caliper is good, or can it still be the problem, even if it feels normal? Are there any other parts besides the guide pins and pad carrier that ought to be clean/inspected/regreased? Are there any installation issues which could cause rubbing?

I am not sure if the dragging is constant, or increases with use/heat.

[paul85]

I use brake cleaner to clean up the old grease in the rubber boots where the carrier pins reside. You might also want to replace them if any are torn. Also, are your new pads chamfered on the leading edge? Sometimes they will stick and rub if they are not bevelled or chamfered where they make contact with the rotor.

Lastly, did you clean your rotor with brake cleaner when you replaced the pads? Sometimes it can get contaminated with grease or dirt and cause the pads to stick a bit.

[tomgabriele]

I use brake cleaner to clean up the old grease in the rubber boots where the carrier pins reside. You might also want to replace them if any are torn. Also, are your new pads chamfered on the leading edge? Sometimes they will stick and rub if they are not bevelled or chamfered where they make contact with the rotor.

Lastly, did you clean your rotor with brake cleaner when you replaced the pads? Sometimes it can get contaminated with grease or dirt and cause the pads to stick a bit.

I didn't specifically clean the boots - I'll do that this evening. Didn't notice any tears though. Dirty/clogged pins would be a nice cheap and easy answer...

Pads are chamfered. Rotor is clean.

Thanks for the help.

[hightime80]

I have a factory passenger caliper that was in perfect shape when I took them off for my s4 brake upgrade.you can have for $40 shipped. Pm if interested

[Spike00513]

http://www.ucx.com/documents/squareseal.pdf

?

[tomgabriele]

That could be it...any way to test for that besides disassembling the caliper?

[logan09]

How was it before changing the pads/rotors? I did mine a while back with drilled/slotted rotors and new pads all the way around. My fronts and rears were really tight. I had noticeable rubbing/dragging when driving. It was kind d of embarrassing hearing the pads in constant contact with the rotors.

Put maybe 500-1k miles on them and they're quit as they should be(well minus braking because of the holes and slots)

[tomgabriele]

How was it before changing the pads/rotors? I did mine a while back with drilled/slotted rotors and new pads all the way around. My fronts and rears were really tight. I had noticeable rubbing/dragging when driving. It was kind d of embarrassing hearing the pads in constant contact with the rotors.

Put maybe 500-1k miles on them and they're quit as they should be(well minus braking because of the holes and slots)

I am actually not sure how it was before. That one was warped pretty good, which could be an indication that it was dragging before too...

[Gin+]

Rubber line collapsing maybe? I've never heard of it happening on a VAG vehicle but worth checking into perhaps. My money would be on a rusty or warped caliper/piston although you claim retraction is smooth.

[tomgabriele]

Rubber line collapsing maybe? I've never heard of it happening on a VAG vehicle but worth checking into perhaps. My money would be on a rusty or warped caliper/piston although you claim retraction is smooth.

The rubber line looks fine to me, no deformation or cracking. It is looking more likely that it's done internal resistance in the caliper. Maybe a sticky or swollen seal not allowing it to spring back as it should.

Anyone have an opinion on rebuilding vs replacing calipers?

[Spike00513]

The rubber line looks fine to me, no deformation or cracking. It is looking more likely that it's done internal resistance in the caliper. Maybe a sticky or swollen seal not allowing it to spring back as it should.

Anyone have an opinion on rebuilding vs replacing calipers?

They're not supposed to be kinked.
The inside is lined with a PTFE/teflon tube. I hear some people on other cars stick to replacing rubber brake lines/hoses every 100k mi.
I installed Goodridge SS because a secondhand set popped up, at a decent price.

[diagnosticator]

The brake pad carrier bracket on the caliper, developes wear grooves where the pad backing plate sits on the carrier bracket. In order for the brake pads to slide sideways, the wear grooves must be filed smooth. It is also possible that the hanging caliper is doing this due to the different position of the caliper piston with the new brake pads installed. The piston is sealed by a square cut seal ring. When the brakes are applied, the square seal ring twists in the groove it sits in when the piston moves out. When the brakes are released, the square cut seal ring untwists and pulls the piston away from the rotor just enough not to rub much. It sounds like the hanging caliper is malfunctioning and not pulling the piston away from the rotor properly. Replace the faulty caliper.