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Fork seals and bushing replacement

DTMWAP

DTMWAP

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Hello there, I have a leaking left fork seal so I want to replace both seals and fork oil on my 41000 km 2015 NC. I've looked at doing it myself but I think this job requires more of my limited mechanical skills. My experienced mechanic told me to pick up the parts and strongly suggest to replace also the fork bushings while the fork is teared apart. As I looked in the shop manual, and parts catalog, I see 2 bushings listed (items 7 and 8 in image below).

Which one is prone to wear? Should I buy both?

1694184045619.png
 
Both are wear items. 7 wears on the inside and 8 wears on the outside. I would pull and examine them before replacing them out of hand. Honda generally gives a specification of replacement when 75% of the Teflon coating is worn off and at 41,000 km I think that is doubtful.

Edit: I think it happens often that the upper bushing gets shown to the owner with the admonition “Look here. The coating is gone and the bushings need replacing.” Thing is there never was any coating on the outside and that surface is the one pointed out. Even DIY owners get fooled and will post “The bushings were shot at only 30,000 miles.”
 
Last edited:
dduelin said:
Both are wear items. 7 wears on the inside and 8 wears on the outside. I would pull and examine them before replacing them out of hand. Honda generally gives a specification of replacement when 75% of the Teflon coating is worn off and at 41,000 km I think that is doubtful.

Edit: I think it happens often that the upper bushing gets shown to the owner with the admonition “Look here. The coating is gone and the bushings need replacing.” Thing is there never was any coating on the outside and that surface is the one pointed out. Even DIY owners get fooled and will post “The bushings were shot at only 30,000 miles.”
Click to expand...
Thanks Dave, I'll have a close look inside of item 7 to see if they really need a replacement. I will order items 7 and 8 as well as item 16 (seal and dust cap) to get everything on hand when doing the job with my friend mechanic. Local Honda dealer told me I can get a refund if part 7or 8 not needed.
 
So, I got all parts and fork fluid to do the job. I'm considering doing the job myself as I have spare time while my friend mechanic is very busy these days. I have the shop manual and a reference video in which, alas, the guy is only replacing the seals. I don't know if what he did was correct as I noticed he forgot a step in the procedure of the shop manual: "with the front brake applied, pump the forks up and down several times to seat the axle and check brake operation" before tightening the axle pinch bolt.


This raise question #1;
Is this video reliable, what do you think?

I have question #2 for those who already perform this fork maintenance;
Do you think my 2015 NC with just over 41,000 km needs new bushings?

And question #3 regarding the new bushings in their sealed packaging;
These dark spots we see, is this normal?

Thanks to you guys!

20230912_Fork_Bushing_3847a.jpg
 
I don't recall having those dark spots on the bushings when I've replaced them. However, I'd guess it's just oxidation of the bronze. I wouldn't be terribly worried about it if those were bushings I'd just bought, so long as there isn't any on the wear surfaces (where the teflon or molybdenum or whatever coating is). You can probably remove that if you find it unsightly. Try your fingernail, and of that doesn't work try some emery cloth.

OTOH, if that _is_ the wear side (I can't see which part is inside-wear and which is outside-wear), then you have a major problem because the low-friction coating is basically all gone. I do NOT think that's what it is. I mention this only for completeness.
 
Going back to Dave's post, this is item 7 in the parts list and he says it wears on the inside so maybe not to worry. But I don't know why this part seems to have some kind of copper coating on the outside.
 
I have not done the fork seals and I have 91k km on the bike. Each time I have had a fork leak I have been able to clean out the area and stop the leak.
 
DTMWAP said:
Going back to Dave's post, this is item 7 in the parts list and he says it wears on the inside so maybe not to worry. But I don't know why this part seems to have some kind of copper coating on the outside.
Click to expand...
Cut and pasted from Google Search: They [Honda OEM fork bushings] are manufactured from hardened steel and coated with copper for added protection. The contact surfaces are a PTFE material designed to give low friction on the moving parts. What Does Copper Corrosion Mean? Copper corrosion is the corrosion of materials made of copper or copper alloys. When exposed to the atmosphere, copper oxidizes, causing normally bright copper surfaces to tarnish. After a few years, this tarnish gradually changes to dark brown or black, and finally to green.

The dark spots are oxidation of the copper coating on the non-bearing surface and like MZ5 posted are of no consequence.
 
I’m with Dave. I replaced my seals and oil at 30,000 miles and bushings were fine. You definitely want to bounce the front end to realign — I forgot that when I did it and the bars and forks were a bit cockeyed so I had to go back and do the bounce.
 
Oh, BTW, the guy in the video is using brake/clutch spray cleaner on fork metallic parts; is it the best stuff?
 
It works pretty well to clean off oil, if that's what you mean. I don't recall feeling like I needed to have dry, oil-free parts the last time I swapped bushings & oil. In fact, one wants well-oiled bushings prior to assembly.

If you use a degreaser, remember to flush it away with fresh oil. Even though those products appear to dry out quickly, they generally leave a residue which either chemically decomposes or competes for surface area with the oil you're going to refill the forks with. I'm not suggesting this is a big problem and your front end will collapse if you don't wash off the degreaser. Nevertheless, I suggest pouring oil over any surfaces you've chemically degreased prior to installation of the bushings or seals, and re-assembly.
 
I also forgot to address your question #2--

I replaced mine the first time at around (very, very generally) the same number of miles you've reached. I may have reached that mileage in noticeably less time, though. I felt like I could have left the bushings alone. There was distinct wear on at least one, but I don't know that it warranted immediate replacement. I had the forks apart for servicing and Gold Valve adjustment anyway, so I just replaced them. It was pretty cheap and reasonably easy given what I was already doing.

The only way to know for sure is to look at your bushings and decide for yourself, unfortunately.

P.S. My forks started weeping a bit later on. That seems to have been primarily a function of scratches on the fork tubes, which my local shop tried to 'buff' out (and succeeded reasonably well), and some low-stiction fork seals I had installed from an aftermarket outfit. I doubt I'd go with those aftermarket seals next time around. I don't think the forks on these bikes, even with Gold Valve emulators or similar alternatives, are good enough for the average rider to detect any benefit from the reduced stiction (if it's even real).
 
potter0o said:
I have not done the fork seals and I have 91k km on the bike. Each time I have had a fork leak I have been able to clean out the area and stop the leak.
Click to expand...
How did you do clean out? My left has started to leak but I live on a gravel, sand, dusty road and I want to try to clean it.
 
The Seal Mate tool works exceptionally well or you can use a similar shape cut from a milk jug.

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Seal Mate Will Fix Your Leaky Fork Seals Guaranteed!

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