...To compressing the pistons on the front calipers? I'm trying to replace pads and I can't compress the pistons. If i push one in the other one comes out, if I try to compress both at once it just won't go. Obviously the pressure behind the pistons has no where to go. What am I missing?

 

Compress the first one with a c-clamp, vise grip, etc. Keep it compressed. Then compress the other piston as well. The fluid will be pumped up into the master cylinder.

 

When I did mine I did one side at a time... Removed cap off of brake reservoir and used a large C clamp to compress the piston.. Replace pads and pump brake to set the new pad... Repeat the other side, and or the rears and when finished top of reservoir.
It may be a good idea to clean the piston with some brake cleaner before you compress it as I found by doing this on my Harley I don't have problems down the road like a caliper that drags. I will be doing a routine clean of my pistons this fall when I paint the calipars on my s/cab...
Hope this helps.

 

No-Tyme, I probably wasn't real clear with my explanation, it is one side of the vehicle, I was refering to the dual piston caliper.
Brian, I didnt have much success your suggestion, although it is a good one. I ended up cracking open the bleeder, not the way I wanted to go, but it ended up working out, pedal is still solid.
Thanks guys.

 

I never would have figured it would do that. Hell, I just put the old pad in, c-clamp slowly and boom, 2 pistons compressed. Fluid goes up and back into the resevoir, clamp too fast and it comes back down on you from the resevoir.

 

there is a tool you can buy for this but i don't know what it is called, my neighbor has one. But you can use a wrench and put it across the 2 pistons and use a clamp to compress them at the same time and then they should stay compressed as long as your resivor tank is closed, don't open it. I did this for my friends dodge ram and he had 2 pistons so i hope this helps

 

Try a piece of 1/8X2x6 inch plate steel to lay across both piston and then put a C-clamp on it.