Hey dude, yes there is! The rear caliper on the MR2 Mk2 works as the handbrake as well which is self adjusting! For this to work the piston doesn't simply push back in, it has to be twisted back in! In other words it has a ratchet system so as the pads wear, the caliper self adjusts to keep the handbrake tight! You really need to take the caliper off the disc before you can wind the piston back in! It's kind of awkward because its hard to get the caliper off if the disc has a lip on it! Not sure if there are any

'tricks of the trade' to help?! Maybe someone with a bit more knowledge than me can help further!!

Hope its gets you going in the right direction though!

Good luck, Stu