So I've got the wheel off, and got the old ones out, I go to pop in the new ones and they won't fit. I can't push the pistons any further in. I didn't know whether I was just being a wimp and not pushing hard or what, so I got someone to step on the brake pedal and one of the four calipers pushed out, but not the other three. It now won't go back in. Now I'm just confused on what to do. Do I need to take the caliper off to reinsert the pads? This is on the front end of a FD. I've looked at the workshop manual online (how I figured out how to get out the old pads), and it said to just reverse for installation, but I couldn't fit in the new pads.

Sorry if I kind of repeated myself a bit, I'm pretty tired right now.

 

Did the piston push all the way out?

You'll need to use a c-clamp to get all 4 pistons all the way in.

 

yes, and the c-clamp isn't putting it in, I'm pretty sure I'm going to need a new caliper.

 

You can rebuild your current ones. Most likely, they just need to be cleaned out, wet sand the pistons a little, and then reinstalled. The rebuild kit is around $30 to rebuild both front calipers (depending on where you get it):

http://www.mazdatrix.com/getprice.as...m=49-2400-FB05

 

BTW, be careful trying to push that piston back in. If you don't apply even force and it gets crooked, you can damage the piston and/or the caliper.

 

What are you using to "push the pistons"? You need something that will push them in straight, and that you can apply some decent force with. I suspect your problem might be with your piston-retraction technique.

The old, worn brake pads serve as a useful device for retracting the pistons. I used to use the smooth-edged metal handles of a pair of adjustable wrenches to pry between the rotor and an old pad to retract the pistons. A c-clamp and the old pad might work well also (never tried it), but you have to unbolt the caliper from the car to get clearance (since the rotor would be in the way).

Also, I have noticed that some pads come with some shims already installed, which can result in not enough room to install both sets of the stock shims. Keep the stainless ones if you can only fit one set of stock shims. Or even run without them if you need to for a little while, and then install the shims later when the pads wear down a bit.

-Max