not very difficult , you need to undo the vacuum advance & aadvance plate [ 4 screws ] & drive the roll pin out of the lower shaft & slide off the nylon ring that limits upward travel of the shaft , & remove the small circlip inside the top shaft , there is a small piece of jute like material in the top of the shaft & the circlip is under that , then you will have a bare housing & can get to the the bushings