Stuck brake pistons

Hi, y'all.

So today, after successfully getting the new rotor in place and old caliper in place and attempting to insert my fresh brake pads, I couldn't get the lower right caliper to squeeze back in. This is on the front right tire. So it would have been the lower, outside most caliper.

Here's my question. Is it possible that there's just air in my brake line, and they need bleeding, or with a quad-caliper (if that's what it is called) brake system like on my 2005 tacoma the caliper either needs to be rebuilt or replaced?

I've already ordered a new caliper, because I have so much to do beyond just this tire that messing around for another 3 hours just to fix one piston isn't viable. I can see on the piston itself some serious build up as far back as you can pull the rubber boot. I tried to clean that up as best I could but it's very gritty. So my intuition is telling me: it's an old caliper and the piston is rusted. It would make sense, as it would probably be exposed to the most debris and dirt while driving, being closest to the road and trapped between the hub and wheel.

Any tips first thing in the AM that might cause this piston to instantly release, before I drop $80 on the new one.

Thanks.

 

Did you replace the pads successfully on the other side first?

The pistons are sticking out pretty far. The reason I ask is if you compress the pistons on the other caliper without pads in either caliper you may have pushed the pistons past their seals. When you tried to push them back in the may have cocked sideways a little jamming against the seal.

 

Those pistons are all way overextended, the boots are supposed to sit inside the groove on the piston. If the pistons aren't rusty or pitted you can rebuild the caliper with a rebuild kit from Toyota, you can even get new pistons fro Toyota if necessary, but at some point it's probably worth buying a reman caliper and saving yourself the time and hassle.

 

Buy the new caliper and tear the old one apart to see how it works and do a full brake fluid flush.

 

Its not uncommon for pistons to seize on these 4-pots.

Re manufactured is a good option to swap in.

 

My vote is for a remanufactured Caliper followed by a full brake fluid flush. This caliper is used on so many Toyota (possibly Lexus trucks too?) vehicles, so the remans are cheap- the $65 for a remanufactured OEM is well worth your time spent removing, replacing the pistons and seals.

 

Update:

Got a re manufactured caliper. It's installed and looking good. Will see if the front left one also needs replacing; I am doing the bearing on that side as well.

Thanks for the input, everyone.