Topic: Fork seal install direction...

[Master Ted]

Warlock is quoted in FAQs: "The seal should be installed with the seal lip facing upward(out)".

This source indicates generally:
"For proper installation, the seal lip should point towards the medium being contained"
http://mechanical-components.globalspec.com/LearnMore/Mechanical_Components/Seals/Oil_Grease_Seals

I have also thought the spring loaded lip should be facing the medium contained such as with a rear engine seal, for example, where lip/spring side faces towards front of engine.

I'm double checking here as an old set of forks I've acquired has the seal lips facing out just as Warlock describes above. Confirm which direction the seal lip/spring should face and why?

[kslrr]

Good question since I have not done fork seals in a long time.  So I looked in my 350f manual.  It does not indicate but I have always thought like you "For proper installation, the seal lip should point towards the medium being contained".  Also, if a fork seal is any thing like a shaft seal (engine, transmission, etc.) pushing on the spring side would damage the seal.  But if what you have face out(up) maybe that is correct.  I will not know until I rebuild the forks on the CB650 (right side leaking).

[Bodi]

Fork seals unquestionably, definitely, unequivicably, now and forever, absolutely always must be installed with the open side towards the oily bits - this allows internal fork pressure to tighten the seal; if reversed it will blow oil out every stroke. Some seals have both sides open, the deeper one faces inward (this is the actual oil seal) and the shallow one faces out (this is a dirt scraper).

[BobbyR]

Fork seals unquestionably, definitely, unequivicably, now and forever, absolutely always must be installed with the open side towards the oily bits - this allows internal fork pressure to tighten the seal; if reversed it will blow oil out every stroke. Some seals have both sides open, the deeper one faces inward (this is the actual oil seal) and the shallow one faces out (this is a dirt scraper).

I just replaced my seals with OEM Honda and they are blowing oil. Smooth out for me top and bottom. I have another set coming on Thursday along with new dust caps, I want to do it right this time. I wanna ride not sit the garage all Summer.   

[jaknight]

Hello All,

     The surface where you can see a spring in the semi open circular pattern............
     that is down, as toward the bolt-on caps on the very bottom of the forks.......

     ~ ~ ~ jaknight ~ ~ ~

[BobbyR]

Hello All,

     The surface where you can see a spring in the semi open circular pattern............
     that is down, as toward the bolt on caps on the bottom of the forks.......

     ~ ~ ~ jaknight ~ ~ ~

Thank you Sir!!!!!!!!!!!!!!!

[Master Ted]

I say the FAQ on the matter needs correcting...

This past winter I installed my new seals with lip/spring side IN the foot case and I'm yet to leak after 3k miles.   

[mrbreeze]

The numbers stamped into the seal should be at the top...at least with Honda seals.

[ic455]

Fork seals unquestionably, definitely, unequivicably, now and forever, absolutely always must be installed with the open side towards the oily bits - this allows internal fork pressure to tighten the seal; if reversed it will blow oil out every stroke. Some seals have both sides open, the deeper one faces inward (this is the actual oil seal) and the shallow one faces out (this is a dirt scraper).

mine had both sides open, I installed deep side in, as described, with no problems.

[Bodi]

"Smooth out for me top and bottom" - you mean the seal ends were flat on both sides?
Well, that's a new type to me. If there are letters on an outer face then I would put that on top. You may be able to see which way the lips point or scrape - the rubber ridges should point inward. But I don't know how a seal without the outside of the lip part - where you usually see the spring - exposed would be able to use the internal pressure to aid sealing.
If you put the normal seals in backwards and try to use air assist on the forks, the air will just hiss out through the seal as you pump it in. With seals installed the right way around the air pressure lasts for a long time. The pressure makes the seal tighten on the fork tube.

[tbone]

The lip that sticks up (away from the seal) goes up or to the outside of the tube. That's what's called a wiper. It removes any debris from the tube so the debris doesn't get into the seal and damage it. There's another lip inside the seal that faces inward (towards the center of the circle). That's the oil sealing part of the seal. That's the part that goes down.

[BobbyR]

"Smooth out for me top and bottom" - you mean the seal ends were flat on both sides?
Well, that's a new type to me. If there are letters on an outer face then I would put that on top. You may be able to see which way the lips point or scrape - the rubber ridges should point inward. But I don't know how a seal without the outside of the lip part - where you usually see the spring - exposed would be able to use the internal pressure to aid sealing.
If you put the normal seals in backwards and try to use air assist on the forks, the air will just hiss out through the seal as you pump it in. With seals installed the right way around the air pressure lasts for a long time. The pressure makes the seal tighten on the fork tube.

Well I took out a pair of "No Leak" seals which lasted 3 years. I went to Honda and ordered a set. They look different than the non OEM. I do believe that one side had a number. One side had a chamfered edge. The official Honda manual shows a flat disc, so much for that. I reckoned that the camfer should be at the bootom to aid in seating the seal. Now maybe I have it backasswards. I ordered new seals, dust boots and circlips. I will examine the forks with a magnifying glass, buff them mirror like. If they still leak, I will set it on fire in the driveway and go buy a Shadow.

[tbone]

"Smooth out for me top and bottom" - you mean the seal ends were flat on both sides?
Well, that's a new type to me. If there are letters on an outer face then I would put that on top. You may be able to see which way the lips point or scrape - the rubber ridges should point inward. But I don't know how a seal without the outside of the lip part - where you usually see the spring - exposed would be able to use the internal pressure to aid sealing.
If you put the normal seals in backwards and try to use air assist on the forks, the air will just hiss out through the seal as you pump it in. With seals installed the right way around the air pressure lasts for a long time. The pressure makes the seal tighten on the fork tube.

Well I took out a pair of "No Leak" seals which lasted 3 years. I went to Honda and ordered a set. They look different than the non OEM. I do believe that one side had a number. One side had a chamfered edge. The official Honda manual shows a flat disc, so much for that. I reckoned that the camfer should be at the bootom to aid in seating the seal. Now maybe I have it backasswards. I ordered new seals, dust boots and circlips. I will examine the forks with a magnifying glass, buff them mirror like. If they still leak, I will set it on fire in the driveway and go buy a Shadow.

New fork tubes are available at Cycle X for $149.00 for stock length. 

[mrbreeze]

"Smooth out for me top and bottom" - you mean the seal ends were flat on both sides?
Well, that's a new type to me. If there are letters on an outer face then I would put that on top. You may be able to see which way the lips point or scrape - the rubber ridges should point inward. But I don't know how a seal without the outside of the lip part - where you usually see the spring - exposed would be able to use the internal pressure to aid sealing.
If you put the normal seals in backwards and try to use air assist on the forks, the air will just hiss out through the seal as you pump it in. With seals installed the right way around the air pressure lasts for a long time. The pressure makes the seal tighten on the fork tube.

Well I took out a pair of "No Leak" seals which lasted 3 years. I went to Honda and ordered a set. They look different than the non OEM. I do believe that one side had a number. One side had a chamfered edge. The official Honda manual shows a flat disc, so much for that. I reckoned that the camfer should be at the bootom to aid in seating the seal. Now maybe I have it backasswards. I ordered new seals, dust boots and circlips. I will examine the forks with a magnifying glass, buff them mirror like. If they still leak, I will set it on fire in the driveway and go buy a Shadow.

....go ahead and get the Shadow but...DON"T YOU DARE!!! torch the 750!!

[BobbyR]

Just kidding I have an emotional attachment to this little B*tch.

[mrbreeze]