Leaky fork. Again.

[kinch]

Hey all, I replaced the seal on my front fork not too long ago and it immediatley started leaking again. Not nearly as bad as when the first seal just seemingly gave up all interest in holding back oil but after only a day of very light riding it had a small trickle of oil that almost reached the bottom of the fork.

When I replaced the first seal I noticed that the ledge in the fork that the seal sits on has a nick. Not just a faint scratch but a good little indented nick (should have taken a picture when the fork was apart but I didn't). I read that any pitting will greatly increase wear on the seal but would that cause oil to get through on the first day? I assume the answer will be yes but any info would be appreciated.

If that is the most likely cause of the problem is there any way to repair the nick or is the fork usless?

[Nessism]

No nicks, scratches or metal pits on the inner stanchions in the area that sweeps across the seals is critical. A nick on the outer slider, where seal seats, should not create a leak.

[kinch]

Sorry, I'm not too familiar with the parts terminology. The mark is where the red dot is, would that cause a problem?


If it shouldn't be an issue do you have an idea why it still might be leaking?

[hampshirehog]

Fork seals can leak there if the seat has been butchered by someone trying to pop the old seal out. However, it usually needs to be more than just a slight nick. If it is scored, a light sand with fine grit to remove any raised scarring and fill with e.g. JB Weld (allow to harden before fitting new seal) will sort it out cheaply.

[kinch]

Thanks Nessisim and Hampshirehog

[tfb]

Another possibility is that the bushes that fit (i) on the end of the fork tubes, and (ii) inside the top of the outer, just below the seal. Bush #(i) is shown in all fiche diagrams, but for earlier models bush #(ii) is not shown even though it's there.

If these bushes are excessively worn, then there will be too much freeplay between the fork tubes and the fork outers, and the seals will fail pretty quickly.

Whenever I've bought a GS, whenever I've fixed leaking seals, I have also replaced the bushes as a matter of course. And I've also used 'wet and dry' paper to remove all rust pits etc. After that, no problems.

[Killer2600]

And I've also used 'wet and dry' paper to remove all rust pits etc. After that, no problems.

What grit sandpaper, I ask because I once again have to replace my seals. I account the pits I have and didn't remove the last time to be the reason for having to do it again so I wanna do it better this time so it'll last more than a year.

[tfb]

I used 800 grit, which is quite fine.

Anything coarser might get the job done more quickly, but there's no point trying to get rid of the rust pitting if all you're doing is wearing away the rest of the chrome before its time, eh. 8-[

[Clone]

The seals also have a definite top and bottom even though they don't look like it. If it is installed upside down, it will leak, when I have a score mark where the seal installs, I find a little rtv before putting the seal in will take care of the problem.

[wilmas2cool]

600 to 800 grit to remove dents and burrs, then polish with buffing wheel and rouge has always (so far) solved fork seal leaks. Developed a real bad attitude when having to replace seals just one month after new installation.