So I was changing the bake pads of my disco II. Everything went well on the driver side, however, the passenger has turned out to be quite problematic. I was unable to get the bottom bolt of the caliper undone, so I was planning on replacing the brake pads with the bottom bolt still on. I pushed the left piston in all the way, which in return pushed the right piston out even further. The problem I am faced with now is the right piston will not go in! No matter how hard I squeeze the pliers the right piston will not go in. Am I doing something wrong? Is there a trick to pushing the piston bak in? Did the right piston possibly get pushed to far out?

 

Crack open the bleed screw and push the piston back in using your fingers. It probably popped out so you need to push it back in square so it doesn't bind. Having the bleed screw open will make this easier.

Also, learn to push the pistons back in while the old pads are still installed using a small pry-bar or large screwdriver. It makes everything alot easier.

 

I cracked the bleed screw and still cant push it in.

 

Get that bolt out what ever it takes , heat with torch & hammer to break it loose than try a C clamp on piston .

 

If the piston is sticking, you mat find your will need to rebuild or replace the caliper or that brake will drag or pull all the time.

 

get yourself a rebuilt or used caliper, it you use any type of heat on the caliper
(to remove the broken bleader)the rubber o-rings will become junk anyway.

 

One problem with front calipers is that if one fails and you only replace/fix that one, there is a chance of brake pull when stopping, so be prepared for the fact that both may need to be done.

 

Piston will go back in.
You should pull the caliper off now - before you wreck it.
Then - get cardboard and put it round the piston.
Then use channel lock pliars to grip the cardboard which will grip the piston.
Rotate the channel locks until the piston breaks free.

Be careful of the rubber seals too.

once the piston is out, clean up the bore and put it back in.
You may want to rebuild the caliper with seals.

It will probably leak if you don't put in new seals or rebuild it.

 

There is a scratch near the bottom of the piston, about an inch long. Do you think that could be preventing the piston from going in?

 

Perhaps.
First, remove it.
Then clean up the bore.