Leakproof seals or not?

I understand from Rabers in San Jose that people are not using Leakproof seals like they once did. Seems that there have been issues with them and some are swearing off them. I don't know exactly what the issues are. The way the person at Rabers put it is that where a few years back most used Leakproof seals for their forks, now the usage is about 50/50 with some saying they would never use Leakproofs again. Does anyone have experiences or thoughts on this?

I have had them in my 75 for about 4,000 miles with not even a hint of a leak, But who knows what could happen? Chuck.

I've read reports of fork "sticktion" when using leakproofs. Enough so that I decided not to use them on my own bike.

There are some things that need to be done to help them work. You need to file some groves in the top of the high hat bushing to give them enough oil to live long. But the number of people getting ten years of leak free service from them tells the tale. I guess people just love spreading bad news.

maylar said:

I've read reports of fork "sticktion" when using leakproofs. Enough so that I decided not to use them on my own bike.

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But how many of those leakproof seals actually get fitted correctly, with the correct gaps, so they can float as the makers intended them to do?




Fitted as original equipment ("self-aligning seals") on '78-'79 model Triumph twins, a kit was (and still is) available (2x seals & 2x washers) so they could be fitted to the pre-'78 OIF Triumph twins, however it appears that many owners press those Triumph interference-fit kit washers down tightly on top of the seals when they fit them!

Leakproof seal fitting instructions: http://www.britishcycle.com/Manuals/Lea ... alInst.pdf

Leakproofs were still fitted to my '78 Bonneville's forks when I bought it, with the washers still installed correctly, giving the necessary clearance, with no signs of any leakage , even though both stanchions were badly worn.
I fitted new Leakproofs when I rebuilt the forks, which so far, have given no trouble.

I am not able to follow what is different between the two types of seal. I have them in mine, since about 1981 or so...same seals...and I've had mine apart perhaps 3-4 times to clean out tubes and I change the oil every 3-4 years or so...too often perhaps, but I've never noticed a strange look to them or some strange way to fit them. Just back in and back together. How do these things then work? What's the trick that supposedly makes them leak proof? Mine don't leak...or haven't up till now I will say, Knock on wood...but now I'm curious just what the big deal is about installation and by the way, what the heck is "sticktion"?
Thanks...

hewhoistoolazytologin said:

I am not able to follow what is different between the two types of seal.

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Instead of having a rigid structure, like a normal oil seal, that has a smooth outer diameter and would normally be a tight fit inside the fork seal housing, leakproof seals are pliable, they also have seal lips on their outer edge and no garter spring, so the seal can move around inside its housing.

hewhoistoolazytologin said:

what the heck is "sticktion"?

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I believe the word is actually stiction?: http://en.wikipedia.org/wiki/Stiction

Forks suffering from stiction tend to react more slowly when they are subject to compression or extension, as the seals or bearings "stick", causing the fork action to be sticky and/or jerky in operation.

Thanks...

Seem to think that mine, which indeed are now legally antique, are formed just like the normal seals and fit in just as the normal ones too. Been a while since I had them in the hand and I think that when I have had the forks apart for cleaning, I have just knocked the sliders off the stantions and left the seals sitting where they were and gone about my business. Logic would tell me there would be no reason to pull them off the stantions if I planned on re-using them. Logic...that is. Strange stuff...logic.

Speaking of logic...if you read the wiki thing, it says that this stiction is a force that happens when two surfaces are against each other, and the surfaces kind of glue to each other until some force causes one to overcome the stiction force the other is using to hold it and starts to move. Motion overcomes this stiction force...or? How in God's name will this stiction stop or slow down the fork slider action on a moving bike? Don't know about yours, but my roads here keep the forks a workin. So I see no sense in this fear of stiction in this case. Sounds more like there is such a good seal in there, that the forks act like a balloon and the compression of the forks has to fight the air pressure in there and this "stiction" has nothing to do with it. Bet a breather hole in the fork cap would cure it's asthma...

Guru time!

The space the seal has to move is important it allows the slider to gain some momentum before it must do work. This helps with stiction if there is the proper amount of oil in and around the seal. The space also keeps the seals from having to do work over road textures that beat on stock seals. But if you use them without gators that cover the leg they will go away from bug guts. And if you run them dry the double lip seal will grip.

I run Gaitors since I installed those "leak-proof" seals in 81.

Still not convinced though that this has anything to do with "stiction"...might be not thinking clear here, but the oil above the seal thing sounds like the oil is more used to help make a good tight seal and keep the rubber wet. Just makes the seal "seat" better like when you install a felt seal and have to soak it over night before installing it. Wetness seals, dryness leaks...

Then again, I'm no genius :wink: