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Leaking forks

Posted: Sat May 27, 2017 4:21 pm
by saltysealion
Hi,

rebuilt my forks because they were leaking. One side has held well now but the other is leaking.

I have replaced both dust and oil seals, o-rings in them with genuine parts.

What other causes could there be for such leaks? The sanctions on the leaky side looks good.

Re: Leaking forks

Posted: Sat May 27, 2017 11:56 pm
by Davez29
Have you possibly torn the edge of the seal while pulling it down the stanchion. Best use a thin oiled plastic bag over the end of the stanchion while sliding the seal into place.

Re: Leaking forks

Posted: Sun May 28, 2017 12:59 pm
by saltysealion
I did protect the seals when sliding them over carefully. The other side isn't leaking.

I will get a chance to inspect them when I pull them off but at the moment, I think they are fine?

Re: Leaking forks

Posted: Sun May 28, 2017 2:36 pm
by magg
Worn bushes may be causing seal lip distortion, that lets oil weep past.

Re: Leaking forks

Posted: Mon May 29, 2017 3:13 am
by saltysealion
I'll get new bushes for this next tear down to eliminate that possibility as well... I did inspect the when I had the forks apart and they looked fine. No major marks or anything but maybe it just has wear on it.

Should I replace the guides as well? That is replace:

51414MW4003
51415MW4003


Ah, the one thing stopping me from enjoying the bike!

Re: Leaking forks

Posted: Mon May 29, 2017 4:31 am
by magg
An indication of any movement can be obtained by removing the dust and oil seals and then fixing the inner tube and rocking the outer tube at various extensions. Also the outer tube inner surface can become worn oversize by the inner tube guide. New guide bushes unfortunately cannot remedy this condition.

Re: Leaking forks

Posted: Mon May 29, 2017 5:43 am
by saltysealion
Magg, do you mean the sanctions may just be over worn?

Re: Leaking forks

Posted: Mon May 29, 2017 6:21 am
by magg
Worse case, yes. The teflon coated bushes might be intended to slide easily but they still appear to wear away at the aluminium surface, possibly because suspension forces distort the alignment of the telescoping tubes. Better designs, Ohlins and some up market Japanese types use a fixed upper bush inside the tube, so that the steel inner tube always slides on the teflon surface and never touches aluminium.

Re: Leaking forks

Posted: Wed Aug 09, 2017 2:35 am
by saltysealion
Just to close up this thread, I did another rebuild on just the leaking fork.

I replaced the oil seal (again) and bush. Nothing was visually wrong with the existing OEM seal I took out, but I replaced it anyways. I used a quality after market seal since I did not have an OEM at hand.

So far no leaks so I am very happy. My bike feels great and STAYS great.