the other day my dad and i discovered that the seal on one of my brake pistons was broken and he recommended i replace the piston. also the pads were worn and the top pin (forgot what it's called) that holds the pads was missing. how much will all this cost? but specifically the brake piston?

 

Look on ebay, I bought some brake calipers (brand new) for under $30. You can get some deals.

 

i couldn't find a piston though... anyone know?

 

The piston is part of the brake caliper itself, I highly doubt that many companys besides Nissan make it for your car. So if you bought it through Nissan it would be very expensive. Just buy brand new calipers on eBay for under $50 shipped that have everything in it, the pin, the piston, and brand new pads.

 

Unless the caliper piston is damaged (eg. pitted or other wearing seen AFTER cleaning it up) all you need is a rebuild kit (seals)...