I am trying out a modification on the kingpins on the +4. I installed the bushings 3/16" deeper into the sliding axle top and bottom and installed an hydraulic ram wiper in the space resulting. The wiper is like an oil seal but stiffer and wipes the pin clean as it enters the bushing. It is advisable to take the sharp edge off of the annular groove in the kingpin where the oil comes out from the "one shot" system with a file so that it doesn't cut the wiper during installation. I've been running them a month and everything seems copacetic. The wiper is called a "canned seal 1.000x1.250x.125 NBF" Besides keeping the dirt out, these seem to keep the oil in as well.
