The rim on my 93 Camry heats up only on one wheel. Is it a caliber piston?

The rim on one wheel is heating up, smells like burnt brake and I assume it is a stuck caliber piston?
I used wd40 on it after taking the wheel off. Any other suggestions or ideas?

Front or rear?

WD40 is not good around brakes. It could be a stuck caliper. Can you compress it with a C-clamp? It could be the caliper pins need lubing with brake grease. Lastly, it could be a bad rubber brake line collapsed internally. It would not let the brake fluid out of the caliper.

“I used wd40 on it”

Yeah, on second thought just take it to a mechanic. Fixing your brakes for the first time is the last thing you want to ‘learn on’.

After 17 years I think a new caliper is prudent, along with a new flex line. However, I agree with Texases that a shop is in order here. Brake repair is best left to an experienced mechanic.

It’s the caliper or the rubber flex-hose…To determine, open the bleeder and see if the caliper piston retracts smoothly as you pry it back…If it does, then it’s the rubber hose blocking return fluid flow…

Everyone starts somewhere. If you really want to fix this yourself go and buy yourself a Haynes or Chilton manual and see if it’s something you want to tackle.

As has been said, it sounds like a stuck caliper, whether it’s the caliper or the hose which is the problem takes further research on your part.

Brakes aren’t difficult but if you do it wrong the consequences can be unwanted.

Most likely you have a bad caliper…I assume this is on the front of the car? They get most of the abuse/use so I bet it is. Replace it…they cheap…then you bleed the brakes.

If it’s the rear, it could be a stuck emergency brake.

Oh…yup surely

I love that Caddyman knows about the rubber flex hoses that collapse and block fluid flow…sharp my man…very sharp. I can count on one hand the number of people, myself included that would have mentioned that…

If it’s the fronts, the car is 19 years old and my guess is the caliper is hanging on a slider or the piston seal in the caliper has become a fossil and not retracting the piston when the brake pedal is released. Or both.
This would mean fix both sides even if one is still good;or good for the moment.

Is that what does the majority of the piston return OK? The seal does this? I always pondered that…

Sort of. The piston slides inside a “square cut O-ring” as it clamps the pads to the disc. The O-ring is designed to distend, in most cases the O-ring slot being beveled on the pad side to allow it to in a controlled manner. When the pressure is released, the square-cut O-ring returns to its original shape, slightly pulling the piston back.

Envision having a faucet washer on a rod where the washer ID is slightly tight around the rod OD. Push the rod through the washer a bit and the washer ID will distend. Release the rod and the washer will pull the rod back a little as it returns to its square cross-section. That’s exactly the way a caliper releases.

Mountainbike is exactly right.

Attached is an “exploded view” drawing of a brake caliper. In this case the “square cut O-ring” is referred to as a “cylinder boot”. It’s a sightly different approach to do the same thing. The “boot” is retained by the “set ring” and pulls the piston back. As the pads wear, the cylinder halves close along the slides.

Pictures are worth 1000 words.

A bad wheel bearing can also transfer heat to the wheel.

Oh sure…Ive seen those o rings before…and I knew there was deflection…I just didn’t put 2 and 2 together to realize what that deflection would do to the piston after it relaxed…very interesting… and when the piston get rusty and doesn’t behave this compounds the releasing of it even more methinks.

Usually it’s the slides that cause the sticking. Usually of a piston is sticking it’s due to crud. But you’re right, crud matters.