Brakes- siezed piston
 

I have an 85' GS I just did the GSL-SE swap on. The rear brakes were fine, acted normal and bleed fine. The fronts would not bleed. I removed the caliper only to find that the piston will not budge. I have them soaked in penetrating oil overnight
I'm asking anyone who has encountered this and the best way to free it? Ive tried a C-clamp to try to get the travel started, no avail. used wood and mallet, no-go.
This is my daily driver so kinda without a car right now.
Help Please.

If it's seized that badly, you're probably going to end up having to replace piston, caliper, or both.

That being the case, for a daily driver, I would myself bite the bullet and go with a rebuilt caliper to get back on the road, and then futz with the borked one at my leisure, maybe salvaging it as a spare.

Remove the caliper. Leave the brake line connected. Push the brake pedal. Piston should be pushed out by the hydraulic pressure. Be careful. If its stuck good it may fly several feet if it pops loose. You can also use compressed air to blow through the brake line hole to force the piston out. I would agree that you'll probably need a new/rebuilt caliper. Got mine at rockauto.com.

Go rebuilt. When I was doing my brakes I had mine rebuilt all around. Wasn't ridiculously expensive and was a huge improvement.

Just get a rebuilt. I'd do both the driver and passenger side. They are actually pretty cheap.

will the calipers of my GS mate to the GSL-SE?

No. The GSL-SE are larger I believe.

if your going to follow 74RX4 advise, PLEASE place a block of wood in place of the brake pads to cushion the blow. That piston will have ALOT of force behind it when it pops out and your body will take the brunt of it if not prepared.

On that note, as my aunt says "fuck the dumb shit" and just get rebuilt calipers. You will save much time cursing and busted knuckles to save a little money.