Don't damage the bushings

[terry hay]

I was reading Rcannons post regarding a ridge on his bushings from his YZ. This ridge is the beginning of the delamination of the teflon coating. If you follow the directions in most workshop manuals they will tell you to split the tubes by slidehammering them apart. The problem with this method is that it is the very process that causes this delamination. The seal creates a lot of resistance that has to be overcome before you can split the tubes. The slidehammer method requires the outer bush to impact with the inner bush in order to force the seal out of its housing. The I/D of the outer bush and the O/D of the inner bush are so close that often during the slidehammer process one bush slips over the other one and both can get damaged. This is common with the KYB forks but not as common as on the dual chamber Showa units. There is a simply way to avoid this damage. Fill the fork completely with oil. Try to minimize the possibility of an air pocket within the fork. Next turn the fork upside down and remove the dust seal and the retaining clip from the oil seal. Now place the fork in a press. once you start compressing the fork you will see the seal slowly rise up from its housed position. As soon as the seal is free, release the pressure and remove the fork from the press. Disassemble the fork and the tubes can now be split with no damage to the bushings. USD require more regular bushing changes than conventional forks but if you can prolong bushing life by avoiding unnecessary damage, all the better. If you don't have a press you can easily rig something up using a car jack and an immovable object. Protect the fork caps from damage by placing a socket or similar item over the cap nut before you begin pressing. Also, just in case you haven't removed all the air, place a rag around the seal area to avoid a Maxima shower as the seal comes loose.
Regards
Terry Hay

 

[Rcannon]

Awsome post...I think this is exactly how I damaged my bushings. This will save me 50.00 next time!

Does the oil go squirting all ofver the place when the seal pops out? I would almost rather spend the 50.00 that have my wife b' at me for an oil mess!

 

[RM_guy]

That's a great idea terry! Thanks

Rcannon,
If there is no air in the forks it won't spray when the seal pops out. Air will compress and act as a spring and that's what makes the oil spray out.

 

[georgieboy]

Just a little offtopic.
Couple of weeks ago i bought a few used marzocchies for my huskie. One leg was leaking due a blown o ring down in the axle-clamp and the other was performing strange, so i took them apart(also out off curiousity sakes).
Well, After I separted them with applying heat to the outer-leg area, this frees the bushing a little, the teflon bushing looked new and replaced the o-ring and some shims as they were destroyed. Now having them back together i feel a noticeable amount of free-play between the outer and inne-leg. But they are not leaking. And i am also happy with the almost none friction. So pls some thoughts about this free-play.
Never noticed this frreplay on my conventionals though. So is this freeplay something of usd forks?

 

[Rcannon]

I canot imagine the fork being designed with a bunch of freeplay. It would appear to cause some funny wear and binding .

My forks work great with my MX tech bushings I just installed. I was bummed about the extra 50.00 or so I had to spend, but the bushings fit much better than stock parts.