Fork Seal Leaking............again

[Bill Alexander]

After my rebuild was completed at the end of 2010 my forks didn't loose a drop for about a year. Then one side started leaking, and I don,t mean just a little bit. The oil was coming out and running down the staunchans at quite a rate. Happened fast - went from no oil to lots - didn't seem to develop slowly.

The fork tube chome is in very good order, no pits or scratches that would damage the seal to that extent, and I have not run any excessive air pressures in them. I figured I just had a dud seal and replaced it.

After 2 months the new seal started leaking again, big time again. The other day there was a pool of oil around the tyre after I had left it parked for a couple of weeks.

The seals I used were OEM, and as I have said there doesn't seem to be any physical reason for them to get damaged. Anyone struck this sort of problem before ? - any ideas what might cause it ?

[DannyMotor]

Wrong seal size. Accidental scoring of the inside of the seal from sliding it over the tube.

Before going medieval on your forks... try this trick. Go buy a roll of Kodak camera film. Cut a 2 inch strip out of the film roll. Wrap it around your fork leg and slide it between the seal and tube. Roll it around a few times. Allow the squared edge to collect any debris. Pull the film out and clean the area with a dry rag.

Lastly spray a little dry lube on your seal and downtube. Check your oil level and go for a ride.

If this doesnt fix it your outer fork lower maybe scored beyond repair.

[dr_fosg8]

How are your fork springs? Do you get a lot of dive when braking? Only time I have seen one go like that was either from badly pitted forks, or bottoming out frequently.

[Bill Alexander]

How are your fork springs? Do you get a lot of dive when braking? Only time I have seen one go like that was either from badly pitted forks, or bottoming out frequently.

Doesn't dive much or bottom out and no pitting or scoring. As far as I can tell even if the fork is bottomed out the seal would still be on clean smooth tube. Does excessive fork movement cause increased oil pressure on the seal ?. It has seemed odd to me that the forks continue to push oil out days after a ride - I would have thought the oil would drain back to the bottom.

It may be just a random coincidence but it just occured to me that the leak first started when I stopped using the bike on a daily basis and now use only every week or so. (reason for that is a long story). I can't see any logical reason that would cause the leak so there is probably no connection.

[Bill Alexander]

Wrong seal size. Accidental scoring of the inside of the seal from sliding it over the tube.

Before going medieval on your forks... try this trick. Go buy a roll of Kodak camera film. Cut a 2 inch strip out of the film roll. Wrap it around your fork leg and slide it between the seal and tube. Roll it around a few times. Allow the squared edge to collect any debris. Pull the film out and clean the area with a dry rag.

Lastly spray a little dry lube on your seal and downtube. Check your oil level and go for a ride.

If this doesnt fix it your outer fork lower maybe scored beyond repair.

Thanks, will try that trick.

The seal seemed the right size and was from the local dealer so I think it is right. There is no scoring on the tube so I guess I can't rule out that I did damage it when installing. If the trick with the film doesn't work I am going to have to replace it again so will have to be extra careful this time.

[mike_of_bbg]

Probably not as applicable to the OEM seals, but is it leaking around the inside or the outside? I put "leakproof" seals in that started leaking after a year, but I noticed it was around the outside of the seals. LP seals actually move up and down with use about 1mm or so, so the surface prep of the fork lower is important with those, too.

[hampshirehog]

Check you popped the seal in the right way round (numbers on top). Plus does the stanchion move around inside the fork lower (side to side)? If so it's time for a new fork lower .

[mrbill5491]

When you get your forks apart, straight edge the sliders and make sure there isn't even a slight distortation in them to make sure they are fine. Odd that your fork would still be pumping oil out when parked for awhile, that says to me it has been building pressure some how.

[Rover]

You are using air in your forks? Might have something to do with it,especially if it is too much.

[gearheadE30]

I think some of the leaking when parked probably comes from oil filling the dust boot above the seal, and then leaking out when the bike is parked. That's what my 750 did, but it had ridiculously pitted forks. New seals lasted about 2 months of normal riding. If you haven't already, maybe pop the dust seals up and check for pitting underneath them when the suspension is in full rebound. Sometimes moisture will build up under the covers if the bike isn't being used often or if it was ridden in the rain and then sat for bit and the tubes will start to rust.