Tractor Repair: Brakes on inter 684, oil leaks, o rings

Question
How can i fix the rear brake on a international 684 tracktor. thanks

Answer
Hello,

  I'm assuming the pedal goes all the way down and the brakes do nothing because that's the most common problem.  You can try bleeding them out first, but that usually helps only for a short time and then it happens again.  To determine if it's the master cylinder or the brake itself, remove the brake lines from the master cylinder and cap or plug the fittings on the master cylinder.  If the pedal is hard and barely moves, then the master cylinder is OK and the problem is in the brake.  If the pedal still goes down and is mushy, then the problem is in the master cylinder.  To repair the brakes, the wheels and axle housings must be removed which means the fenders and fuel tank must also be removed because they are attached to the axle housings.  It's a pretty big job and can be quite time consuming.  The o-rings on the brake pistons tear or flatten out and the oil leaks out from behind the pistons.  Remove the pistons and replace the o-rings, but when the pistons are installed, they must be pushed in perfectly straight and square with the bore or the new o-rings will be ruined again.  There is a tool that looks like a big T that bolts onto the tractor and presses the pistons in straight.  Inspect the brake disks and even if they aren't worn out, make sure they are absolutely flat and not warped.  

                     Arnie