Pajero Shogun ABS problems

[Moz Mechanic]

Good day
I have a Pajero Shogun 1996 Model and are experiencing enormous problems with the brakes.I have replaced the brake pads fron and rear and since then my problems have started.The righ rear wheel will start locking by it self and does not want to release.This only happens once in a while but I cant figure out what is the problem as I have bled the system looked for seized pins in the caliper area but couldnt find anything wrong.Any body got experience with the ABS systems on these pajeros.Any comments or help will be appreciate.
Thank Johan