Fork Seal Replacement Issue

[WadeScarbrough]

Following a utube video on removing the bottom bolts (drain) of my forks, I used an impact driver to break free the bolts. The left fork (with dive brake) bolt broke loose and came out without an issue. However, the right fork bottom piston began spinning and the bolt would not come out. After along time of drilling out the bolt, I was finally able to disassemble the fork assembly to find the bolt itself still tightly secured in the threaded hole. I was told by a local motorcycle mechanic that I needed to have used a rapid spin air wrench to get the bolt out. Does this sound correct? Is the piston in the bottom of the fork supposed to be free to spin? I’m concerned about reassembly if he piston begins to spin before the bolt tightens against the copper crush washer. Again, the mechanic advised a rapid spin wrench would tighten the piston to the bottom of the fork tube before it could have a chance to spin out. Also,the 8mm x 1.75mm bolt that is shown as the size bolt used seems to bottom out in the threaded hole before it can be tightened against the washer. Any advice would be apprecoated.

[DaveO430]

Sometimes there is more friction in the threads than there is in the piston it screws into and you get that problem. Honda says use loctite on the threads but that is a bad idea. And yes an electric or air impact helps. Usually helps to have the spring installed when removing the bolt. That is an 8x1.25x27, not 8x1.75. The correct bolt will not bottom out before it tightens.

[WingMan71]

... Usually helps to have the spring installed when removing the bolt.

Agreed!

Having the spring still installed in the fork when removing the bottom bolt will make it easier. The spring tension keeps the fork innards from spinning when trying to back out the bolt.

I've always been able to get them out that way using a manual impact driver (the kind you smack with a hammer).

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[MikeB]

You need to know that those two 8 mm bolts have different part numbers, 90116-KV3-701 and 90116-383-721, because they are two different lengths.

I don't know which is longer than the other but bolt part number 90116-383-721 goes in the right fork and part number 90116-KV3-701 goes in the left fork.

I've always removed them with an air impact wrench and reinstalled them with a torque wrench.

[GoldWingrGreg]

The longer bolt goes on the right.