KYB Fork Oil Leak where slider meets axle holder

[mxrcr4]

Hello,

Question for those much more knowledgable.

Under my 03 KX 250 (which has about 9 easy hrs on it) I noticed some fork oil on the floor. Cleaned everything up and next day saw fork oil at the bottom of the slider and it was leaking down over the bottom of the fork where the axle slides through. But slider under the seals was perfectly dry all the way to the bottom where I mentioned. Even pulled the dust seal and it is dry above it as well. Cleaned up again, removed brake stuff, and still same result. It appears to be leaking at the union of the slider where it meets the axle bracket/holder. I am lost here as I did not know anything there could leak.

Thanks,

Brian

 

[marcusgunby]

The slider is screwed to the fork axle holder, sounds like yours has come loose.

 

[mxrcr4]

What approach to tighten?

Thanks, every parts diagram I can find shows it as one unit. What approach should I take to tighten and stop the leak? Put the bottom bracket in a vice and try to screw slider in some? Or maybe put slider in rubber vice pads and try to screw the bracket tighter? Or another method? Thanks a ton!

 

[mop]

mxrcr4:
Sometimes, the axle bracket comes loose from the inner tube, more often on the brake side because of the rotating force the brake action puts on it. But this is usually with forks that have alot of abusive time on them, or if the axle bracket has been removed at one time or another. Your case sounds like a fluke incident. If the axle bracket has come loose enough for it to leak oil, it means that the o-rings inside have been damaged, or the axle bracket has been wallowed out excessively. Your first course of action is to try and retighten the tube into the axle bracket and hope that it doesn't leak anymore. Unfortunately, you will need a set of "soft jaws" to hold the inner tube tightly enough to tighten the axle bracket. Call around to local suspension shops and ask if they have the means to do this. Trying to tighten it by yourself with some kind of protection on the chrome tube while securing it without the proper jig can damage the tube.

 

[mxrcr4]

Thanks guys, I will try the tightening first. If it does not work, I will probably just buy a new lower slider which has the bracket already on it as my cost here is only around $175.00 or so.

 

[Pete Payne]

If you try to tighten it , do not forget to remove the set screw before you try to tighten it . :cool:

 

[mxrcr4]

OK, tried to tighten last night with no luck, of course I read Air Chuck's message to remove the set screw first today! I did see it and tried to remove it, but could not. What kind of screw head is it? It does not appear to be hex, torx, or any other I am familiar with. I did get a hex to fit fairly close and tried to move it, but it did not budge. It also appears to be dinged or punched to keep it from backing out. I have felt I was pretty good mechanically having no trouble doing anything else on these bikes but this one is new and I am clueless here! Any help is so much appreciated, Brian

 

[marcusgunby]

I noticed the same but i have never had to remove one, hopefully air chuck will chime in again as he has done a few.

 

[Pete Payne]

It should be a allen . You will probably have to put some heat on it with a propane torch.
Normaly , I would have the fork completely disassembled and clean. Then would take a propane torch and heat up the area around the set screw, then remove it . apply a little more heat and unscrew the tube . Check out the o-ring. Clean out the old lock-tite , clean and dry both parts and reassemble with red lock-tite. Normaly I would heat the lower fork lug on assembly a little , this will help make sure it is GOOD and TIGHT.

 

[mxrcr4]

Okay, thank you for all the insight. I will give it a shot this weekend. One more quick question, if I need to replace the o-ring, where might I find one? Thanks!

 

[mop]

MXCR:
The set screw is a 3mm allen hex head. BUT after it is tightened, Kayaba stakes it to keep people from messing with it. That is why it looks weird and an allen wrench won't fit into it easily. Sometimes the damage to the socket is not too bad, and a 3mm allen will fit, but usually, you will have to dress it up slightly with a drill or mill bit. You must be very careful doing this. Also, once you get the allen wrench to fit properly, you will have a shallower depth so be careful not to strip it out. You will have to heat it up with a torch to break the locktite, but it will come out. The headache of getting the axle bracket off starts with this set screw fiasco, then continues once you get it out: if the set screw has deformed the threads on the inner tube itself, you must dress them up as well with a flat end mill bit, otherwise you run the risk of tearing up the inner threads on the softer aluminum axle bracket. This is also locktited on and must be heated up, unless it has already come loose from vibration like your fork......good luck!

 

[Pete Payne]

The o-ring should be OK. but, if it does get hurt try MX-tech or Race tech for a replacement. Or a good hose and hydraulic shop should be able to size one up for ya.

 

[mxrcr4]

Wow, thanks guys, great information. Seems there are VERY few people around that know anything about this. It worked like a charm! This forum is such a great thing for all riders of any level. Thanks for participating with very skilled knowledge! Brian