Forum Main Tech Help/Race Shop Issue with fork seals

Issue with fork seals

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J-Pat

Vital MX member J-Pat 59025 J-Pat /images/default/avatar/c50.png https://www.vitalmx.com/community/J-Pat,59025/all 08/09/17 2 3

Posts: 5

Joined: 8/9/2017

Location: Altoona, PA USA

5/4/2018 9:36 AM
Edited Date/Time: 5/4/2018 9:38 AM

Howdy all.

Over the past year, I've been restoring a 1991 KX250 for my father, as he had one way back in the day. The disc side fork seal was leaking, so I tore both forks apart and replaced the seals, as it was making a heck of a mess.

Bought the seals and correct driver (43mm).

Put it back together and....

The disc side fork seal is still leaking. Neither he nor I haven't ridden it at all, and I walked out into the garage to a fairly large puddle of oil on the cardboard I had laid down as a security measure.


What are issues that could cause a brand new fork seal with zero rides to leak? Is there a good way to make sure the fork leg isn't ever so slightly bent? Could bad bushings cause the fork to sit unevenly and weep oil?

Is there an easy way to check wheel alignment to make sure it's not binding the fork?

Thanks!

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seth505

Vital MX member seth505 8912 seth505 https://p.vitalmx.com/photos/users/8912/avatar/c50_IMG_8735_1506991758.jpg?1506991615 https://www.vitalmx.com/community/seth505,8912/all 04/01/08 1 https://www.vitalmx.com/community/seth505,8912/setup 50 7957 74 5

Posts: 8009

Joined: 4/1/2008

Location: SD, CA USA

5/4/2018 9:40 AM

Possibilities:
-the fork seal was put in upside down
-the lower leg has a big gouge/mark in it somewhere
-the seal was damaged when installing it (did you use something to protect it from the sharp edge when slipping over the fork leg?)

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J-Pat

Vital MX member J-Pat 59025 J-Pat /images/default/avatar/c50.png https://www.vitalmx.com/community/J-Pat,59025/all 08/09/17 2 3

Posts: 5

Joined: 8/9/2017

Location: Altoona, PA USA

5/4/2018 9:44 AM
Edited Date/Time: 5/4/2018 9:51 AM

seth505 wrote:

Possibilities:
-the fork seal was put in upside down
-the lower leg has a big gouge/mark in it somewhere
-the seal was damaged when installing it (did you use something to protect it from the sharp edge when slipping over the fork leg?)

-the fork seal was put in upside down

The fork seals have a bit of a ridge in them that the dust seal locks into, not to mention - there's the weird retainer clip that holds the seal itself in. I can check this sometime this weekend

-the lower leg has a big gouge/mark in it somewhere

I actually checked this during the install of the seals. I did not see any marks whatsoever on the leg.

-the seal was damaged when installing it (did you use something to protect it from the sharp edge when slipping over the fork leg?)

I used the wrapper of the seals to protect the seal itself when sliding it over the end of the fork.

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kb228

Vital MX member kb228 61852 kb228 https://p.vitalmx.com/photos/users/61852/avatar/c50_48AD01BA_8BE7_43D5_B767_B4A5D12AFA64_1538263085.jpg?1538262140 https://www.vitalmx.com/community/kb228,61852/all 01/31/18 73 5433 1

Posts: 5510

Joined: 1/31/2018

Location: Mansfield, OH USA

5/4/2018 11:26 AM

They make a product called a “bullet” that slips over the top of the lower leg to protect the seals during install. Its basically a rubber/plastic sleeve with a chamfer on the top. Personally ive always been lucky using the wrapper and suspension oil as lube to install mine and have never had issues.

Another possibility is a bent tube or poor quality seals. Over filling with oil might cause a leak - not sure tho.. never did it.

Also what i do on the seals is put some grease around the outside, where they contact the upper tube. I feel this will help prevent leaks.

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Paw Paw 271

Vital MX member Paw Paw 271 38400 Paw Paw 271 https://p.vitalmx.com/photos/users/38400/avatar/c50_Husky_TC_449_1526420797.jpg?1526420311 https://www.vitalmx.com/community/Paw-Paw-271,38400/all 04/03/13 12 12 3377 1 3

Posts: 3389

Joined: 4/3/2013

Location: Benton, LA USA

5/4/2018 12:49 PM

Yes worn bushings will allow the fork seals to leak. They should always be replaced when new seals are installed.
The seal edges can be damaged if the correct tools are not used. Dirt in a new seal can make it leak. Scratched fork leg can cause the seals to leak.
Always install the seals on the legs prior to installing the bushings.

Paw Paw

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