Topic: Fork Leg Issue: Lower Bolt Sealing Surface Damaged. Fix?

[Trad]

After rebuilding the CB500 forks for my Cb550K build with new Forking by Frank tubes and new seals and crush washers, I was still getting a little seep of fork oil around and below my front hub axle on the brake rotor side.

Anyway, I took it all apart today thinking I'd put a new crush washer on with a bit of copper sealant, torque it up nice and call it a day. Well, not so simple. I took a good look at the surface that the crush washer is sealing against and it's gouged to #$%*. It was leaking from tho area since day one with this bike and now I can see why. Your guess is as good as mine as to why this happened.

I think I am going to take it to a machinist to knock down the material up to the bottom of the gouge. It should only be 5mm or so at the most. That should leave a flush surface for the copper crush washer to seal against. Does anyone see any reason not to do this?

I'd be open to hear suggestions on alternative ways to fix this, or is anyone else has had anything similar happen.

[Brantley]

That almost sorta looks like there's still a crush washer in there. Maybe a previous owner stacked 'em? I'm not positive of this, but a lot of forks I've disassembled look like Hondabond was used as a sealant. Might explain why it's stuck in there. Do a little digging, literally.

[LesterPiglet]

Usually a coppper washer in there I think. A replacement should seal fine.

[Trad]

That almost sorta looks like there's still a crush washer in there. Maybe a previous owner stacked 'em? I'm not positive of this, but a lot of forks I've disassembled look like Hondabond was used as a sealant. Might explain why it's stuck in there. Do a little digging, literally.

There is no copper washer in there. Trust me. haha. I dug the old one out only to find the alloy gouged up underneath. Can you see the gouge I'm taking about? It's allowing fork oil to seep past the crush washer.

[Trad]

Usually a coppper washer in there I think. A replacement should seal fine.

I had a new copper crush washer in there. With the size of that gouge in the surface, it's not sealing.

[LesterPiglet]

Get the correct size drill bit and skim the badness out of it. 

[Trad]

Get the correct size drill bit and skim the badness out of it. 

Yep! haha. I have a 1/2" flat bit that I was so close to using yesterday but then I though getting it machined proper was probably the better way.

[Powderman]

You wouldn't use a drill bit, they have tapered ends. Get an appropriate size end mil and chuck it up in the drill press and just dress lightly the surface and you should be good to go with a new copper crush washer.

[Trad]

You wouldn't use a drill bit, they have tapered ends. Get an appropriate size end mil and chuck it up in the drill press and just dress lightly the surface and you should be good to go with a new copper crush washer.

Thanks for the comment Powderman. in my above comment I mentioned flat bit. AKA end mill. . I am well aware a regular drill bit would mess it all up. haha.

[BobbyR]

You could claen that up well and put some JB Weld in there with a new washer on top of it. The Washer is a new sealing surface and the JB fills the voids and holds the washer in place.

[Djfob]

Ive used hondabond with no washers, worked well and not permanent. Cleaned up easy the next time I redid my forks

[strynboen]

use a  under cutter..there are one spec vith senter tap and 2/4 cutting blates..it takes presise and small material..and does not ruffel up..just go to a mashine shop..dont bay the tool..

[Airborne 82nd]

Think dremel they have bits perfect for that. The poor mans end mill

[Brantley]

That almost sorta looks like there's still a crush washer in there. Maybe a previous owner stacked 'em? I'm not positive of this, but a lot of forks I've disassembled look like Hondabond was used as a sealant. Might explain why it's stuck in there. Do a little digging, literally.

There is no copper washer in there. Trust me. haha. I dug the old one out only to find the alloy gouged up underneath. Can you see the gouge I'm taking about? It's allowing fork oil to seep past the crush washer.

Just throwing it out there; I've missed it before. Optical delusion, I guess. Machining is the way to go for a proper fix, but it might be cheaper to just replace that leg. I haven't seen a 500 leg in a while, but if it's the same as 550k you can swap it for 750k3-k6 or CB500T 75-76. You might also try annealing your copper washer and putting a thin coat of Hondabond on it.

[cadman]

Use #1 hardening Permatex - Let it cure for 24 hours.

[BobbyR]

Put a nice smooth crush washer on tom of that Permatex you have a new fresh sealing surface

[Trad]

Thanks for all the input guys. JB weld with a steel washer was suggested by the machinist if I didn't want to pay for the correct fix. I'm just having him machine it 30 thou and calling it a day. It wasn't THAT expensive. I'll update this with a new photo once it's fixed.

[Don R]

For others, consider a faucet seat refinishing tool. It has a flat cutting surface and a centering pilot.

[HondaMan]

A machinist could make that flat in minutes. That's what I would do. A drill bit has a tapered face, not a good way to go. An end mill is square and flat, and made that hole in the beginning.