Im putting a car back on the road that hasnt been road worthy for 30 year or so. The chassis is completely disassembled and painted. All of the oilers are gone. What size drill bit should i use to clean out the holes in order to install new oilers? should i use red thread-locker on them when i install them? Any other tips and tricks?
Just clean the paint out with a knife and pound them in using a block of soft wood and a hammer. The will be a tight fit so you should not need any lock tight. There were some king pins made that you may have problems with the oilers. They take an odd sized oiler so watch for that.
Check the year of your car / kingpins. Earlier cars had 1/8" pipe threads on the twist top oilers.
Later cars have the flip top oilers that are simply pushed into the hole in the top of the kingpin, as Mark states.
Do as Mark says for the smooth holes. Use a 1/8" pipe tap to clean out the threaded ones. Just don't cut away any material.
Take a small punch or a machine screw and grind it down so that the end fits into the body of the oiler.(top open of course). Not the "tail" section that goes into the hole but the larger main body. The idea is that the punch should hit the flange that's formed inside where the body narrows and forms the tail. Should be a snug but not tight fit. Tap it into the hole with a small hammer. Using this method you will not deform the oiler and correct orientation of the spring loaded cover is easy. Works for me + I haven't ruined one yet.
PS: if their the type shown in Mark's pic just make the punch to fit to the bottom and slightly round the edge of the punch.