Jump to content

Fork Seals - A possible $$ savings and fork seal longevity?


Recommended Posts

My friends and I have debated for a long time now about fork seals. Our fork seals never seem to last as long as they should before they start leaking. Many times, it's that one ride in the mud with new seals where the mud dries on the forks and the fork compression drives the dry mud past the seals into the upper tube...and all of a sudden there's leakage all over the place. We try and try to use the "film negative cleaning technique" which seems to stop the leak temporarily...but the seals start leaking again. I have read that seals leak because of "micro-cuts" and "micro-abrasion"...but is this really true? Or is it just dirt between the seals that cause a gap and thus a leak? Can the seals be re-used? Have the seals really been compromised?

I've read from the experts that "seals are cheap", always replace them...but $45 is $45...and some people would rather spend that $45 somewhere else...especially a couple of times a season. I know I would like to save money...especially since I do my own bike work at home.

So since I have a few microscopes at work in our Quality Lab (in addition to one that's hooked up to a computer for photos), I decided to look at my leaking seals under the microscope and see if the seals were nicked or scratched in any way. I first looked at and photographed the sealing surface on my new seals as a baseline. The old seals were about 6 months old and only began to start leaking with grainy dirt that came out of the cavity between the two seals with every swipe of a film negative. I expected the old seals to have obvious nicks in he seal surface.

After careful examination under the microscope, I couldn't find any evidence of any kind cuts in the old seals. In fact, I declined to take photos of the old seals because they looked exactly like new seals. Exactly like new seals. In fact, I saved my old seals, cleaned them and the next time my fork seals leak, I'm going to replace them with these old seals instead of buying new ones and inspect the ones I take off with a microscope again. My guess is that one set of fork seals can be used a lot longer that previously thought by cleaning the seal / forks and replacing the oil with fresh oil. I know most people don't have access to a microscope, but a 20X-30X jeweler's glass will get you the similar results (purchased for about $10 on ebay).

Anyway, I know your dealer will mandate new seals so as not to accept any liability...but if you are a DIY guy like I am, this little inspectiion and a reuse of seals might save you some money in the long run...especially if you are one of those guys that seems to have leaking fork seals many times in a riding season. My opinion is that it's the dirt in between the seals that constantly pulls the seal lip up and causes the leak...not a cut in the seal. The seals might not be bad after all, they just might need a little cleaning.

(of course, this method is at your own risk...but definitely worth thinking about) :banana:

Link to comment
Share on other sites

I've been able to do the clean trick and replace oil for years on forks

if your blowing them all the time, use seal savers

+1 seal savers are money

Also if your bushings are more then a couple years old or have a lot of hours on them, I'd go ahead and replace them.. Your bushings might not look worn, but every set of forks I've done that leaked again quickly, soon as I did the bushings they didn't leak for another 2+ years

Every set of forks I've done and the bushings haven't leaked in less then 2 years, and/or still aren't leaking to this day :banana:

Link to comment
Share on other sites

I've cleaned existing leakers several times when incorrect parts have arrived, never had a problem on reassembly, seals pack with dirt and start to leak.

Yep, seals on my WR forks seam to leak fairly frequently after a decent wet weather ride. Pop down the dust wiper, quick clean out with brake clenaer and compressed air (low pressure) then a run around a few times up and down with a feeler gauge, then all good an no more leaks.

Reckon I have done it atleast 5 times with this set of fork seals and they stop leaking everytime until the next mud ride. Changed the fork oil the other day and decided to leave them in rather than replacing them.

ive replaced plenty of seals with no dirt in the cavity, so thats not the only reason they leak, if you want long lasting seals, use new bushes, clean the tubes often, and use skf seals.

Yeah dirt isnt the only thing, have found if i get a nick from a rock etc in a lower fork tube, it causes the seal to leak pretty quickly and nothing will fix that apart from replacing the seal and smoothing the nick down.

Are those SKF seal easy to get a hold of now? Heard they offer a fait bit less stiction than oem?

Link to comment
Share on other sites

Yep, seals on my WR forks seam to leak fairly frequently after a decent wet weather ride. Pop down the dust wiper, quick clean out with brake clenaer and compressed air (low pressure) then a run around a few times up and down with a feeler gauge, then all good an no more leaks.

Reckon I have done it atleast 5 times with this set of fork seals and they stop leaking everytime until the next mud ride. Changed the fork oil the other day and decided to leave them in rather than replacing them.

Get some seal savers and I bet you'll get 2+ years out of seals.. Then you just pop off the seal savers everytime you wash the bike good and clean them out

I have over 4 years of use on my honda 150f seals, I just have the oem rubber boots on them... I only remove the boots every 5 months or so to clean any possible dirt, but they are always SPOTLESS inside! And all I ride are nasty muddy trails

Link to comment
Share on other sites

My friends and I have debated for a long time now about fork seals. Our fork seals never seem to last as long as they should before they start leaking. Many times, it's that one ride in the mud with new seals where the mud dries on the forks and the fork compression drives the dry mud past the seals into the upper tube...and all of a sudden there's leakage all over the place. We try and try to use the "film negative cleaning technique" which seems to stop the leak temporarily...but the seals start leaking again. I have read that seals leak because of "micro-cuts" and "micro-abrasion"...but is this really true? Or is it just dirt between the seals that cause a gap and thus a leak? Can the seals be re-used? Have the seals really been compromised?

I've read from the experts that "seals are cheap", always replace them...but $45 is $45...and some people would rather spend that $45 somewhere else...especially a couple of times a season. I know I would like to save money...especially since I do my own bike work at home.

So since I have a few microscopes at work in our Quality Lab (in addition to one that's hooked up to a computer for photos), I decided to look at my leaking seals under the microscope and see if the seals were nicked or scratched in any way. I first looked at and photographed the sealing surface on my new seals as a baseline. The old seals were about 6 months old and only began to start leaking with grainy dirt that came out of the cavity between the two seals with every swipe of a film negative. I expected the old seals to have obvious nicks in he seal surface.

After careful examination under the microscope, I couldn't find any evidence of any kind cuts in the old seals. In fact, I declined to take photos of the old seals because they looked exactly like new seals. Exactly like new seals. In fact, I saved my old seals, cleaned them and the next time my fork seals leak, I'm going to replace them with these old seals instead of buying new ones and inspect the ones I take off with a microscope again. My guess is that one set of fork seals can be used a lot longer that previously thought by cleaning the seal / forks and replacing the oil with fresh oil. I know most people don't have access to a microscope, but a 20X-30X jeweler's glass will get you the similar results (purchased for about $10 on ebay).

Anyway, I know your dealer will mandate new seals so as not to accept any liability...but if you are a DIY guy like I am, this little inspectiion and a reuse of seals might save you some money in the long run...especially if you are one of those guys that seems to have leaking fork seals many times in a riding season. My opinion is that it's the dirt in between the seals that constantly pulls the seal lip up and causes the leak...not a cut in the seal. The seals might not be bad after all, they just might need a little cleaning.

(of course, this method is at your own risk...but definitely worth thinking about) :banana:

Right on!

By the way, the number one cause of seal failure, in our book, is from washing the bike.

It removes a protective layer of lubrication from the tube and often leaves behind water spots that act like teeth.

Clean and lube the tube (and shock shaft) after every ride and your seal life will go from weeks to years.

By the way, you're not going to find any nicks or voids when looking at a seal under a microscope. What makes a seal seal, is a little more complex than that.

Link to comment
Share on other sites

In my local area I find more problems with leaky seals on bikes with seal savers on them. I attribute this to our track being very sandy. the sand gets pushed up into the seal savers every time they ride. after awhile the seal savers are full of sand and it just forces the sand into the seal and makes them leak. most of the time this happens within a half dozen rides or so. Those that have removed them have had the issue resolved. I believe they would work fine on other types of soil but sand doesn't appear to be too kind to them.

Link to comment
Share on other sites

In my local area I find more problems with leaky seals on bikes with seal savers on them. I attribute this to our track being very sandy. the sand gets pushed up into the seal savers every time they ride. after awhile the seal savers are full of sand and it just forces the sand into the seal and makes them leak. most of the time this happens within a half dozen rides or so. Those that have removed them have had the issue resolved. I believe they would work fine on other types of soil but sand doesn't appear to be too kind to them.

My seal savers are removable without removing the forks, so every few rides i clean them out and they work great. They are a must for muddy conditions in my opinion.

Link to comment
Share on other sites

Do you folks use any lube on your fork tubes after you wash your bike? Maybe your tubes are dry and it takes to long for the forks to oil them before the dry fork tube eats up the seals? I use some sort of WD-40 or Liquid Wrench on a paper towel and then wipe the water off the tube with them. When the kid brings the bike in to the pit area from the track. I hit them once more with the oil on the paper towel just after we scrape the mud off the bike. What blows our Fork Seals more then anything else is torquing the bikes down on the trailer and those stupid seal saving brace things we put in between the wheel and fender to stop you from blowing out your seals suck. The first time your wheel moves the brace moves and you take the chance of losing the bike from the trailer.

Oh and what ever you do. DO NOT USE SILICONE TYPE SPRAY PRODUCTS because the stuff will ball up and make the seals leak.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

×
×
  • Create New...