Front brake piston stuck open

[cutter]

I have a 93 camry that's got a firm brake pedal but weak braking performance. No shudder or pulling when braking, just weak overall.

When I checked for glazed pads and rotors (none), the drivers-front brake piston seemed to be pushed in, meaning when I lifted the caliper, I could put it right back down without any interference from the piston. Can this be the cause of the weak brake? Do I hit the piston with penetrating oil and/or bleed the brakes? Trying to narrow down potential causes to troubleshoot this weekend.

 

[Doog]

Probably a corroded piston/caliper. Do not use penetrating oil. Probably time to rebuild or replace. Do not forget you do calipers in pairs. So both need to be re-done. You can try pulling off the caliper and hitting the brake pedal lightly to see if the piston moves. But it needs to move in and out freely so if it is the least bit corroded then a rebuild is in order.

 

[Bgallagher]

I say replace the capiler itself and bleed the system. You can pick up a reman caliper from rockauto for roughly $20. It isnt worth messing around with a part that can be replaced cheaply

 

[Quest]

I'd replace the whole caliper assembly (rebult ones ok) instead of trying to resolve it yourself.

No use rebuilding a caliper assembly if your piston already seized inside (due to corrosion, etc.)

Q.

 

[2oldtommy]

You are in the salt zone usage area in PA. On a car almost 20 years of age it is not uncommon to have a caliper lock up. Salt spray finds its way behind the rubber boot and corrosion takes place between the piston and the caliper housing. A set of rebuilt calipers is in order. I believe the '93 camry still had drum brakes in the rear, but check the proper operation of these as well. When replacing the calipers, be sure to include new flex brake lines as well. FWIW---Oldtommy

 

[LeakySeals]

My dad had a stuck caliper on his 06 Avalon and didn't know it. Caused over 1k damage from heat and wear. So if you suspect, replace. If you change pads by squeezing the fluid back into the caliper rather than bleed, maybe a full bleed of the old fluid will bring some repose back.

 

[mechtech2]

Hard pedal and weak brakes, along with an obviously sticking caliper makes sense.
If you can swing it, get 2 rebuilds at the same time.

 

[cutter]

Originally Posted By: Doog
Probably a corroded piston/caliper. Do not use penetrating oil.


If it's corroded and stuck as a result, why not use something like aerokroil?

 

[chrome]

Originally Posted By: cutter
If it's corroded and stuck as a result, why not use something like aerokroil?


Because even if you do break it loose with penetrating oil, the rust will damage the seals once the piston starts moving. You end up with a leak, and need to rebuild or replace anyway.

 

[Doog]

Originally Posted By: 2oldtommy
You are in the salt zone usage area in PA. On a car almost 20 years of age it is not uncommon to have a caliper lock up. Salt spray finds its way behind the rubber boot and corrosion takes place between the piston and the caliper housing.


+1 Consider yourself lucky you made it 19 years in salt.