I replaced the king pins and bushings on my '57 2 ton within the last year. The dust caps do not have any clip or ring holding them in. The king pin is held tight with a tapered pin through the axle bore. I did not have any trouble disassembling the components, dust caps came out with a little careful punch work, the only thing I farmed out was having the new bushings pressed in and honed to fit the new pins. I did all of the work with the truck on cribbing and the axle in the truck.

1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy