Black dust buildup after just 30 miles only on driver side rear wheel of ‘86 944

[Morfstar]

Scratching my head on why all of a sudden I have very fine black dust accumulating within just a few miles and only on the driver side rear wheel of my ‘86 944. Comes off easily with a dry rag but as soon as I put a few miles on it, it comes back and just on that wheel. Fronts and rear passenger side are clean as new. Car only has 37k miles, been well serviced, hasn’t seen rain in 20 years, and the only squeaks I hear occasionally are from the front, what’s happening? Thanks all

[azbanks]

Did you change anything with the tires or brakes or suspension on the car?

[Morfstar]

No changes, just started happening. I only drive it once every month or so. It’s like a years worth of brake dust that accumulates in just a few miles.

[944 Ecology]

Use a infrared thermogun to see if that brake is dragging. The rotor should be quite a bit hotter than the others if it is. Could be a sticking piston, rust causing a sticking pad, etc.

[thomasryan]

sticking caliper will be pretty hot. the back of your hand in close proximity will let you know.

buy two calipers. been there.

an increase in fuel consumption is the first sign.

flush the brake fluid every two or the every few years even if you don't drive it much.

[Rasta Monsta]

Also handbrake shoes can drag.

[Fast Freddy 944]

Black powder? Break dust....Check to see if a break is grabbing or dragging....Mechanical issue for sure..

[Jfrahm]

Yes and remember to change your brake fluid every 2 years. Much cheaper and easier than doing it when you are replacing calipers or an ABS pump.