Fork seals - one or both?

[GD2]

Normally, if I have a leaky fork, I order parts for both forks and replace them.

But it occurred to me that just because a seal may be old, doesn't really mean much. It either works or doesn't. So why replace both if only one is bad?

I am sure there are a ton of by-the-book people who replace everything. My question is for anyone who only replaces the bad one. Just curious how many are out there?

[Rambozo]

Depends on if I knew the history. On dirt bikes I would often replace just a single seal or sometimes just remove it, clean the crud off, and put it back. Leaks were usually from debris, and a seal-mate couldn't always get it all.

[WingAdmin]

Whenever I have to replace something that requires a lot of disassembly and time to get to, I will generally ALSO proactively replace other life-limited parts that require the same disassembly. My time is worth more than a few dollars extra on another seal or whatever.

[MikeB]

Whenever I have to replace something that requires a lot of disassembly and time to get to, I will generally ALSO proactively replace other life-limited parts that require the same disassembly. My time is worth more than a few dollars extra on another seal or whatever.

I feel the same. It requires a lot of time and disassembly just to remove one fork tube assembly. Removing the second tube assembly is a matter of three more bolts that have to be loosened.

[Neal12]

Don't replace either one until you've tried the SEAL-MATEs to fix the issue. Many of us have used them for years and I've yet to hear of anyone not having success...For just the $8.00 price

[MikeB]

Don't replace either one until you've tried the SEAL-MATEs to fix the issue. Many of us have used them for years and I've yet to hear of anyone not having success...For just the $8.00 price

If it is just a slight oil seep, then a Seal Mate is a great option. If there is a large volume of oil lost, enough to foul a brake disk, then disassembly is the only option. As always, it is a judgement call.

[jfrank]

I have faced that dilemma twice. First time I replaced both with after-market parts- sliders and seals. A few years later I, another leaky fork occurred, and I bought a single Honda fork seal kit. The service desk salesman questioned did I want two sets to which I replied no, only one. I noted the tone of the question as one of, "You'll be back." The extra expense of OEM parts made me think why replace the second fork's apparently good seals. Well, a few thousand miles later, the second fork began to leak. Tear the front apart again to get to the second fork. New Honda seals and back on the road.
So, my advice is to replace both when you have the bike down, unless you really, really enjoy the task.

[GD2]

I did the job and decided to just do the leaky one and keep the extra set for whichever seal leaks next (if it happens).

Mostly because there is no "shelf-life" for a fork seal. It's good, or it leaks - age doesn't matter. And removing all the plastics and getting the fork off took me around 40 minutes by myself. The tear-down of the fork took a little while (maybe another 30min or so?), but was not that bad - especially since I only did one.

And... for the purists... I used ATF to refill the forks. I've been running AFT for a short while and it works fine for me, and I had it on hand.

[Yoyosk]

To much work for one. Don't forget to oil or grease to be put back in or u will probably be doing again. Besides you should be changing oil. Honda says yearly

[Rambozo]

Mostly because there is no "shelf-life" for a fork seal. It's good, or it leaks - age doesn't matter.

Like all rubber parts there is a shelf life for fork seals. Without oil on them, they will eventually get hard as a rock.

Never tried storing new seals submerged in ATF, might work, might not.

[GD2]

Never tried storing new seals submerged in ATF, might work, might not.

Did someone suggest doing that?

[SIDECARRICH]

Well even though I am one to always replace both on my 99's, I had just done both back in 2019 on this one when I bought it and knowing that only the left was leaking (Chicago potholes thank you) I did order both kits but just this week only did the leaking one.

[MCRider64]

This past Spring, I replaced the seals on both of the forks of my 2008 1800HPN- OEM parts, done by the dealer. Well, not exactly. The dealer rebuilt one fork assembly. On the other one, the bottom bolt would turn, but it would not screw out. Something broken inside the assembly. So, this assembly was replaced with a NOS unit. My opinion- for any labor- intensive job, always do both. You never know what you will find!

[shspvr]

As a rule you should do both never just one fork seal

[GD2]

As a rule you should do both never just one fork seal

I guess I am just a rebel.

[01196505gw]

This post caught my eye after just earlier today noticing a strange and significant puddle of fluid under my front wheel. What tha??!
So I guess I'm looking at this replacement. May I assume there is a thread here on Docs that provides guidance? I'm handy enough with tools so may I also assume this is something I can do? And what IS the best source for new seals?

[Neal12]

See my previous post first.

[01196505gw]

Good point. Sure can't hurt to give it a try.

[GD2]

This post caught my eye after just earlier today noticing a strange and significant puddle of fluid under my front wheel. What tha??!
So I guess I'm looking at this replacement. May I assume there is a thread here on Docs that provides guidance? I'm handy enough with tools so may I also assume this is something I can do? And what IS the best source for new seals?

There is at least one good video on Youtube as well.

[01196505gw]

Thanks GD2. I'll check that out also. Fingers crossed on the seal tool. I'm going to give that a try. I have to say I have not paid much attention to any fluid on my forks, so no telling how long ago this may have started. But over the last week or two, both of them have started oozing. I will try my best to give a progress report.

[GD2]

Folks used to do a similar trick as the Seal Saver by using a piece of 35mm film.

[Bike...and Dennis]

Folks used to do a similar trick as the Seal Saver by using a piece of 35mm film.

Nowadays, I find it less effective to use to use digital files.

[01196505gw]

Ummm, before we get too far off track... -is there a means of changing the fluid without disassembly?

[Rambozo]

Just pull out the drain plugs and pump the forks until empty. If you have air caps, you can remove the air fittings and refill. If not, you will have to pull the caps.

[01196505gw]

Back on 12/2/23 I posted some questions concerning leaky fork seals; actually tried the plastic seal tool, but just didn't get any satisfaction with it. Anyhow went ahead and pulled it all apart and redid the seals and bushings. Kind of a messy job, but I've been in worse. I also replaced the springs with the progressive springs.
Also seemed like a good time to replace the rear brake disc and pads as well.
So all back together now waiting for this 12°F in southwest Ohio to reflect some global warming.
Thanks to all who offered answers and advice.