rizzoss669

Was driving around in the mountains of Colorado this weekend. At one point I was going downhill for about 20 minutes at least. I was admittedly riding the brakes a lot. After a while, I could feel the brakes getting squishy so I pulled over. The right rear was smoking. I squirted some water on all wheels and it fizzled off the calipers and rotors like a hot stovetop. The brake pedal would easily go all the way to the floor.

My question, is there something wrong with the truck (2003 4runner) or did I just ride the brakes too much? I think perhaps I caused the fluid to boil and that made it lose pressure? Would new fluid/bleeding help? After about 30 minutes of cooling things seemed to go back to normal. I just don't want to deal with this again.

Thanks!

Fink

You definitely overheated the brakes. If you're going downhill for that long, I would recommend resting the brakes by using a lower gear, or just stopping and letting them cool down periodically.

I would definitely replace the fluid and bleed the lines just to be sure the fluid itself is still good. If for no other reason than peace of mind.

Fink

WD_40

Also I would not recommend pouring water on overheated parts as that's a good way to warp and crack things. If your brakes overheat, just pull over and let them air cool.

rizzoss669

Thanks guys. That is what I suspected. I just needed to hear it from someone else. Looks like I'll replace the fluid and stop driving like a jackhole.

blakegeee

Good advice here! Lower gear is a good idea and don't ride the brake continuously. Use it to slow down a bit then take your foot off the brake completely. The Toyota Fortuner, sister to the 4Runner, also has this same issue if you aren't careful.

Again, let them cool naturally by air or you will almost surely end up with warped rotors (or worse) if you throw water on them as the water wouldn't cool them evenly. Just overheating them alone can warp the rotors. When they aren't hot, and you just ride the brake pedal lightly, can you feel the pedal pulsing a little bit? That would indicate that the rotors are now warped.