Lifetime Premium Member
Date registered: Aug 2013
Vehicle: 1989 MB 420SEL, 1991 560SEC
Location: Atlanta, GA
Mentioned: 19 Post(s)
Quoted: 624 Post(s)
To extract that worm shaft out, I made my own procedure. You are welcome to follow it.
I measured the diameter between the bottom of the groves of the shaft and looked for something that was slightly bigger than that, but it can deform a bit. The best I could come up with was a plastic tube from Lowes, I think is from the Plumbing or Irrigation department: a PVC tube.
Rotate the shaft out of the ball cage till you see the first ball appearing. Stop and put the PVC tube with one end against the end of the shaft (but-to-but) with NO space in between. With one hand hold the tube and with the other hand hold the shaft, pushed one against the other.
While you keep both pressed but-to-but, a second person will rotate the entire piston which will transition from the shaft onto the tube. After few inches of travel the entire piston will be only on the PVC tube and the shaft will be released. Replace the hidden o-rings inside and then proceed in reverse order transferring the piston back on the shaft. I found it very beneficial to hold the tube against the wall next to my bench (first picture) and I pushed the shaft against the tube.
Because the OD of the tube is slightly bigger, the the balls will make groves on the surface of the tube which you can see in my third picture. The whole idea is to slide something inside the balls cage as the shaft gets out so the balls will be kept in place and not fall off
I've done it twice and it worked fine, but I had help each time because two hands are not enough.