Is it safe to mix brake fluids? I always put in Dot4 from the gas station because that's the slightly better one (right?) so I figured it couldn't hurt.

 

DOT4 is the proper fluid. You have not been mixing fluids.....

 

Is there a chance Dot3 ever made its way in there? I have no reason to believe so, but if a mechanic or somebody decided to go cheap on me...
What would happen in a mix of Dot3 and Dot4?

 

I'm not sure. I know that DOT4 will take higher temps than DOT3. I don't know if there is any other adverse reaction between the two other than the fact that you're dragging down the temp limit for the fluid.

 

Ok, well I will only put Dot4 in and I don't think any Dot3 actually made its way in (it was completely flushed with new fluid a few weeks ago so I'm sure I'm fine), I was more just curious.
I figured it would just bring down the boiling temp but then again when you mix coolant....

 

the rear calipers need to be twisted in / screwed in. use your needle nose pliers and just duct tape them to the correct width to match the dimples on the piston. turn in clockwise. the front calipers can be compressed with channel locks or even a wood working clamp. And dot 3 and 4 are only different in boiling point, so don't worry unless you are racing.......always use a new container of Brake fluid because they will absorb water after they are opened, which ain't good.

 

I have ordered the "turn while compress" brake kit from ECS, so I just need a new caliper and a free saturday.

 

I only replace a caliper if it won't screw back in. or the piston boot is leaking. very rare both. You won't know if you have a problem until you try to screw it back in. if it won't 'catch' when screwing clockwise, turn it back a quarter turn counter clockwise, then back clockwise, and then it might catch and screw in. Parts changing always works, but is very expensive. and you can borrow that tool you bought from ECS from AZ or Advance. good luck.

 

If your inside pad is gone it will lock up also, check that first may just need pads n rotors