I rebuilt all four of mine when I did my complete brake overhaul. Bought the refresh kits for each caliper (new rubber seals & the like) online and it was straightforward but a pita. If I have the coin next time it needs it I plan on buying new calipers.

If the $$ isn't a hindrance you will be better off buying new. It will definitely take less time (rebuilding was a day & 1/2 job for me). Also you will need access to an air compressor to blow out the pistons on the calipers. I don't have one and it was a pain in the @ss to jury rig something up to make it work.

Just my 2 cents...

 

I had my L-R brake sticking, I ordered a rebuild kit, tore it down only to find that the piston was swelled?? causing it to stick. I had to hone the caliper bore just to get the dang piston to go back in, it was a pain. I try to save coin, but I think I will buy new the next time I need caliper work. I still have rebuild kits on the shelf..... Oh and my rear left is working good.

 

One more thing. If you do go the rebuild route then I'd suggest buying all new pistons (which can get up there into the why don't you just buy a new caliper price range) to go along with the rebuild kits.

My reasoning is that if you are going to reuse the old pistons then you will find that they are most likely covered with rust patches and you will spend a hour or so scrubbing and sanding the rust off.

 

Yes I agree. Plus, the pistons are made of pot metal or something, and I swear they swell over time.....who knows..