my 1.7s left front calipers are due for a rebuild bad! im working on the left front and got one piston out but the other is stuck like is welded. got it to move back but no farther forward. any one got an idea?

Start with compressed air.
If that does not get it out, make a fitting for a grease gun and fill it up with grease, that will get it out...but it messy.

Rich

I'll usually peel off the dust seal and fill the space between the piston and the bore outside of the O ring with Rost Off or PB Blaster, let it soak, tap the outside of the caliper with a hammer a little bit, let it soak, and then squeeze it back in just to get it moving. Then I'll put the loose piston back in and C clamp it or hold it with pliers so it won't come out, put a small piece of wood in there so that the tight piston won't slam into the pliers if it comes loose and put some compressed air into the hard line hole and blow the piston out. It may not come out right away, you may need to squeeze it back in and blow it part way out several times to get it out.

Compressed air for what you have described will almost never work unless you try some of Steve's recommendations. You may be able to buy a $20.00 can of Gunk carb cleaner (gallon can) and leave the caliper in there for a few days. That would probably do it.

What is holding the piston is basically what I cal brake shellac. It's a gummed up fluid/rust combo that will buff right off with a buffer wheel but it will glue your piston in there like it's welded in.

If you have air, you can't go wrong with a $13.00 Harbor Freight grease gun. Take a 14mm spanner (just trying to get a reaction from this side of the pond) and remove the tip. The threaded portion is now 10x1 and will screw directly into your caliper. You'll need to block off the open bore, a large rubber washer and a steel plate can be made for this (Lowe's). C-clamp it in place and simply pump out your piston.

Fluid doesn't compress, air does.

i've had to remount the caliper on the strut and bleed the brake system and use the brake pedal to push out a stuck piston. next time i have to rebuild a caliper, before i remove it from the strut, i'm going to remove the pads and put a wood shim between the piston and rotor and push the piston as far out as i can, then remove the caliper. hopefully the pistons will practically be out of the bores and then use compressed air to complete the removal.

That's a pretty darn good idea. Have a helper position a couple 1/4" wood shims in there.

I've found that once you break that bond between the piston and the bore, they probably will come out as Jim suggests.

Or if it's an annoying neighbor that won't ever go away you can just ask him to "hold" the pistons with his fingers!

The problem is, with fluid, they simply "plop" out... no drama. Now with compressed air... weeeeeeee.