- Nov 8, 2003
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.