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Fork seal orientation


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3 minutes ago, tony27 said:

They're upside down, the flatter side is always down with the external spring at the top

Great many thanks!

I was actually following this video (see 13:00). So it looks like he’s got it the wrong way too then?



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I’m starting to feel like it’s correct in the original post….

if I look at the way the seal works, oil needs to get up behind the seal to compress it tighter…it looks to me like the low tapered side (with the more visual steel band) should then face the oil (face down).

it would also make sense as to why there is a cup shaped part below the seal, to protect this lip?

or am I talking nonsense?!

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The pressure in in the lower leg on a normal fork so the seal should seal downwards. Looks to be OK in the first photo. I recommend SKF (original at newer evo) fork seals. To protect the seal from damage (easy to do) cover the all sharp edges with some electrical tape and grease or oil the stanchion and tape before assembly. The guy in the movie clip seems to do it correctly

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Seems to be lots of conflicting advice on the internet about this topic….

Not sure if the above photos help? I’ve got the first photos facing the oil side. It has a bigger softer lip that stick out and I assume will be pressurised tight from oil pressure.

However, the writing is on this side and some people say writing should be facing the non oil side, where is can be seen.

If I put the other way, when installing id also be hitting that bigger softer lip with the driver….sure that would damage it.

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The sealing is often (always?) made of radial type seals . This is possible because differential pressure is low and speed is moderate

Pic 1 is the scraper side. Facing upwards. You also have a separate dust scraper above this. The spring is there only to make scraper effect better.

Totally there will be one dust scraper and one oil seal. Your oil seal has one scraper side and one oil pressure side

Pic 2 is pressure seal side. Facing downwards. Oil pressure pushes the lip harder against the stanchion. The spring gives an initial sealing pressure

Some radial seals doesn´t have a scraper lip.

Take the dust scraper away every month or so, and clean under (above the fork seal). This may prolong oil seal life

Put some grease (or similar) on the retaining ring to prevent rust

The retaining ring is above the the oil seal and hold it in place

Edited by carl ekblom
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Thanks all for your advice. I completed the seal change this weekend, built back up, tested, all went well.

Wanted to post here my finding in case anyone is reading this in the future.

Before proceeding I doubled check by contacting the seal manufacturers direct.

Referring to my very original post, the seals were in fact the wrong way around, as most people on this forum advised me (thanks again for your help!)

I learnt:

- the writing on the seal always is on the non-oil side, so you can see it once installed (under the dust seal). Makes sense.

- the protruding lip is a wiper lip for the non-oil side (as other people mentioned).

- didn’t get on the pyramid parts seals (as found on eBay), got odd balls (I think they were called) instead. Seemed much better quality.

- the video I posted above is really helpful.

- it’s fiddly to get the bushes in before the seals, however I ensured the bushes were all the way in and flush before lowering the seal. I think this helped.

- as lots of people say, really check for any damage, scratches, nicks etc and fix before proceeding.

- I made a seal driver from some 50mm blue water pipe. Had to file down the inner and outer edge to make it fit perfectly (I allowed the wiper lip to sit inside the pipe so it wasn’t damaged). In the end it worked great. The nice thing is that you have have a longer length extending above the fork so you can tap it with a hammer. Makes it much easier in my opinion and actually better than a normal seal driver.




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