Removal of XJ-900 Anti Dive top piston Brake Plunger Piston

I think I went through every post I could find on this site about the XJ-900 anti-dive unit, but I didn't find any that details how to get the Brake Plunger Piston out. That's the little piston in the top portion of the anti-dive unit held in place by a 14mm hex screw.




The problem here that the piston shaft sticks up in the middle of the hex recess, so you can't get a standard hex wrench in it. A "tamper proof" hex wrench would probably work, but those are kinda pricey, if you can even find one that big. Len also sells a tool (HCP16049 I believe), though I haven't seen what his looks like.

I found an even cheaper solution though - an m10 coupling nut. These nuts happen to be the exact right size to fit the 14mm hex hole and a 14mm wrench. If you can't find one in your misc parts bucket or local hardware store, you can get 5 of them from Amazon for about 7 1/2 dollars.
https://www.amazon.com/dp/B09TXH93D6

Pay attention to specs when you're looking for one...not all of them have a 14mm hex. Most are larger than that. I think these particular ones are intended for lighting fixtures.

The other problem is holding the body in place while you crack the piston. I found it really hard to get a good grip on it without doing damage. So, I rummaged through the scrap bin and found some 1/8" aluminum bar stock. I drilled a 22mm (7/8") hole through it to fit around the cylinder flange, then drilled holes to run some m5 screws through to clamp it firmly to the bar. The whole thing then clamps in the vice.



Took a little persuasion to get it started, but once loose, it spun right out with no damage.



Now you can install all the new goodies you ordered from Len to rebuild your anti-dive.

Hope this helps somebody else.

 

If I recall correctly, that little piston shaft also has an o-ring on it......I think you can (maybe with a little penetrating oil.....lube up the shaft of that little piston and push it out (in) of the way, and then you can get a regular hex wrench in there. Of course you still have to clamp the housing----and it doesn't hurt to use a torch on the housing to expand it a little----and then with the strength of 10 ordinary men you can crank the plug out.

But the way you did it was much more creative and elegant!