It should take very little pressure at the brake lever to push the pistons out, but as soon as you release the brake lever they should at least stop moving. (it's not unusual that they don't retract, at least on cars) and you should be able to ease them back in slowly and smoothly.
I usually do this with a c-clamp, but if you're careful you can also use a channel lock and some protection from scratching or marring, this will give you a better feel for how easily they go back in (I usually use the back of an old brake pad as a plate to push against and a heavy rag or towel on the other side.) If one was retracting and the other stuck, my guess is that the sticking one is where your problem is. I'm not sure on rebuild procedure for these but I'm sure the guy's here can guide you in it if you like. You could try clamping down the good side that moves easier and just working the other side back and forth a bunch to see if you can free it up some.
I'm not one personally to fool with my brakes. Pretty much if they dont work, I replace the broken part and call it good, but that doesn't mean much.

 

I'm not an expert on the application of teflon in and around the caliper piston seal, but I wouldn't recommend it. Hydraulic brakes systems are awfully picky. The reason you'd use brake fluid for this application is that some of the brake fluid would work into the piston seal and caliper interface and loosen up a sticky piston...if that's the problem of course. You probably wouldn't want teflon residue getting in there, as it may not be compatible with the brake fluid or the piston seal in this case. Teflon doesn't usually hurt rubber, but hydro rubber brake parts can be particular about what they come into contact with. While brake fluid usually doesn't seem to possess much in the way of lubricative quality, in a brake system environment it has some interesting qualities.

 

Sounds like a sticking piston. Try McKay brake cylinder assembly lube. For use on cups, pistons, cylinder walls, orings. Advertises 'frees sticky pistons' on the back.
Extend the piston out of the caliper, apply the assembly lube to the exposed piston wall surface then retract the piston back into the caliper. Repeat acouple three times. Workied for me but it could have been luck

 

hears some questions that may help us with your problem. hold old and how many miles on the bike? how much dirt do you ride and how hard? if the piston doesnt come out evenly like your said, theres something sticking for sure. and for refrence, bike brakes are like cars, they go out and dont return (someone was unsure, so i thought i would answer it). hope we can get you fixed quickly, i know how it is to not have all your brakes, ive been riding without a rear brake for over a month now (bent rotor).

 

Bike is an 07 with @3500 miles. Last time this thing hit dirt was last Spring and that is about 3/year, 95% of the miles are street. And the pistons for sure are not coming out evenly one. After pumping the brakes over and over one is significantly more extended then the other.

 

Another thought: Could the front wheel not be properly aligned with the caliper, that is, shifted right or left?

Ride on
Brewster

 

I don't think so because when the bike is up on the stand and with the front wheel spinning it spins very true and the resistance is even. I hope I explained that correctly.

 

IF the pistons are not extending evenly then is the brake pad contacting the rotor unevenly, and jamming?
At least you are getting a good understanding for how your brakes work. Motorcycles are good for that...

 

It's not uncommon that the pistons extend unevenly in a dual piston caliper with no brake pad or rotor resisting them, so don't necessarily think that because they don't, that is an indication of the problem. And as someone said, they don't retract on their own, it's a hydraulic mechanism, when you pull the lever at the master cylinder, that pushes fluid against the pistons causing them to extend, but releasing the lever only stops the pressure, it does not reverse the flow to cause any retraction.

So there will always be a little bit of drag on the pads as they rest against the rotor. Not a lot, but if you put your bike on the stand and spin the front wheel, it will rub the pads a little bit, it won't be 100% free. Is that all your seeing? Or is it really bad such that it is difficult to even turn the front wheel?

 

Hahahahahahaha.....nice!!! Oh and watch your back.