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Post by Deleted on May 8, 2012 11:50:43 GMT
I've changed one of my front fork seals 3 times in a year now....
The new seal goes in just fine, properly seated, clip and dustseal in place, everything looking absolutly fine, but within 6 months or 5000 miles, they keep failing. I've had the fork completely apart, inspected it with a magnifying glass and can't see anything visibly wrong. I'm out of ideas on this so I thought I'd seek the advice of this wise and learned group as to what else I might check!
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Post by Sean on May 8, 2012 15:02:48 GMT
Is the spring still good? Not broken and giving in too much hence breaking the seal?? Are you putting the right ammount of oil in? Not overfilling it? Is the fork true?? Are you using the right seals?? daft but obvious questions....  Sean |
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Post by Deleted on May 8, 2012 15:15:46 GMT
With no obvious pitting I'd reckon the fork is not true. Easily checked next time it's apart.
Have you checked the whole length of possible travel for even the slightest pitting ? It's amazing how little you need to damage a Fork seal.
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Post by Deleted on May 8, 2012 15:27:59 GMT
Is the spring still good? Not broken and giving in too much hence breaking the seal?? Are you putting the right ammount of oil in? Not overfilling it? Is the fork true?? Are you using the right seals?? daft but obvious questions.... Sean Good list of checks.... Springs are fine, or at least they're still within the "free length" tolerance specification and feel OK while riding Yup proper grade and quantity of oil used, checked both by volume and level Fork was true by eye but I didn't check it against a proper datum so I'll do that next time I have it open! Seals are the right type and fitting properly Checked extremely carefully for pitting and what there was I took out with 2000 grade wet'n'dry and repolished Thanks for the tips, the fork being out of true sounds like the best bet for the problem so as soon as I can get a replacement seal I'll open it up and check that. |
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stav
Boy Racer
Posts: 143
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Post by stav on May 8, 2012 21:46:04 GMT
also check the fork stanchion bushes for ware
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Post by divrider on May 9, 2012 11:32:43 GMT
Had the same problem on an earlier D9 about 5 years ago, seals would last about 3 months. Turned out one of the forks slightly bent. It wasn't noticeable until the mechanic rolled it on a flat surface. New forks, seals (and springs whilst at it) cured the leak.
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Post by Deleted on May 15, 2012 20:36:04 GMT
OK, have had it open to check, the fork is out of true by about 1-1.5mm along it's length, is that enough to screw the seals?
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Post by m40man on May 15, 2012 20:43:10 GMT
OK, have had it open to check, the fork is out of true by about 1-1.5mm along it's length, is that enough to screw the seals? I think so, yes. The seal is prob loosing it's initial flexibility after a few months in situ, & being slightly mis-shapen to the point that leakage occurs. (I'm guessing the leak is a very fine weep? Little more than a misting?) |
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Post by Deleted on May 15, 2012 20:50:55 GMT
OK that sounds quite likely, the leak takes the form of initially just a rather-more-oily-than-normal dirt ring, progressing to visible dribble of oil from the dust-seal down the fork tube, finishing in a rather oily leg for me when I finally do something about it.
Assuming it is a shagged fork tube, I might try to put it in the hydraulic press and re-true it when I get back from the peak district holiday next week, but given the likelihood of that not working, the relatively low value of the bike, and the high price of having the fork professionally realigned and rechromed, I'm guessing I'm going to be in the market for a new bike come autumn
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Post by m40man on May 15, 2012 20:57:32 GMT
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Post by teejayexc on May 16, 2012 7:00:33 GMT
Which model is it, the single or twin disc version?
I've a set of forks for the twin disc, came off a mid 30K mileage bike. In good nick and were working fine when they came off the bike, ( I broke it about 18 mths ago).
Yours for £70 + p&p if you want 'em ?
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Post by Deleted on May 16, 2012 10:04:33 GMT
Thanks for the offers guys but it's the single-disc version. I'll have a go with the press at straightening them when I get back from holiday, then decide what to do.
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Post by Deleted on May 16, 2012 10:12:29 GMT
£86.89 from M&P for a stanchion.
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Post by CD on May 18, 2012 8:42:02 GMT
www.motoliner.com were (a few years ago) covered by Classic Bike mag for straightening frames and fork legs.
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