King pin won't take grease

get wheel off ground. maybe a small amount of heat to center of king on the side pin to soften up hard grease

 

whens the last time you greased it. heat will soften up old grease. even like a plumber torch

 

i would try the heat

 

You can take it off but it won't tell you much either likely. Don't keep trying to pump it in or you will force that cover off and then you have a real mess.

 

Jack both sides off of the ground and turn the wheel to the stop one direction. See if grease well go in. Grease everything on steering with wheels turned. Than turn all the way the opposite direction and grease everything again. Than center and grease again.
This insures that grease gets all the way around the pins and balls on tie rods and the hard dirty crud gets flushed out.

 

If it wont take grease the damage has already begun. Since it's the top bushing unloading it back jacking will likely not do the trick but it wont hurt. Turning the wheel while greasing is your best option. Sometimes I'll take the grease whip off, blow it out and fill with PB or WD and see if that works through. If your using a hand grease gun, take it in the shop and try. The commercial air pump guns can generate more pressure.

To make it right you may have to tear it down.

 

speedco $34