You don't take that piece apart. Take the entire assembly and put it in a spray paint can top and put some wd-40 in it. Take an old toothbrush and brush all of the crud out of the adjuster until the ratchet assembly moves freely. Then dump that WD-40 out and spray the three balls path out with more WD-40 and make sure there isn't any grit in there keeping the balls from moving. When you're done get a good waterproof grease and pack the ball path with it. It will keep it from locking up again. When you reinstall the assembly it will take a few trys to get the spring tension right so you can still pull it easily but it will return fully when let go. If your return is setup correctly the white plastic piece with the blade part sticking off of it will self adjust your rear brakes up so they won't fade out.