Brake Smell and then Total Brake Loss

[Toastybunzz]

I took the car out for a spirited drive and then on the way home I caught a whiff of hot brake pads. I thought it was the new car in front of me that had just pulled out of a dealership and didn't think much of it. I come up to the next light and my foot goes straight to the floor, thankfully the emergency brake did it's job. The car didn't feel down on power but I had to drive the last mile home very slow... I can bring the pressure up if I pump the brakes and after it sat idling for a minute the pedal felt normal.

I'm thinking I must have a stuck caliper but is there anything else I should look for? I saw something about some booster recalls but it doesn't feel like there is an issue with it not returning after stepping on the pedal. Bad master cylinder maybe? It seems odd that a half mile of dragging brakes going 40mph would make them fade to nothing.

It's a 1999 btw, 85k miles.

[Toastybunzz]

I went back out to look the car over. The fluid level is at the max setting, the brakes feel good with the car on and off. No leaks to be found. I did a sniff test on all four wheels and the front right is the only one that has a faint hot brake smell. The car has sat for quite a while, it's probably been almost a year since it's last proper drive.

I think what happened is the brakes got hot while I was driving in the hills and as it cooled a piston seal failed and didn't retract fully. I was doing normal street driving for about 15 mins, it must have been dragging until I smelled it get hot as it boiled the fluid. I don't see any discoloration or visual signs of heat damage thankfully. I think the first order of business is to lift the car, see if there's extra drag and then rebuild all the calipers and change the fluid.

[tonythetarga]

If the seal failed the caliper would leak. I’d flush fluid first and exercise the caliper by pushing the pads back in and using the pedal to push them back out.

[Toastybunzz]

True but I figured if it would drag enough to get the brakes hot it’s worth replacing the seals in case there was some gunk in there. I got it done, it was kind of a PITA but worth it. The wheel definitely spins more freely than the other wheels do, the front drivers side could probably use a rebuild as well (or at least exercise the pistons) but I’ll wait to do that. I’ll have a garage to use in a few weeks to do my SAI and oil separator and I’ll check that out as well.

I usually flush all the brake fluid fairly regularly but I realized I hadn’t done it yet on this car. So it was at least three years old, and who knows how long ago the previous owner did it...