Was it ok to clean the upper control arm mounts? I'm thinking it was just old lube that I removed. I wanted to get rid of any grit before installing the new arm.

What should I use for lube on it? Silicone? The same as on the caliper slide pins?
Also, what is that vertical slot for?

Prior to cleaning (upper ctrl arm mount)



After cleaning (upper ctrl arm mount)

 

Other than the clean area being more prone to rust than the surrounding areas I would say you would be ok if you just sprayed it with a coating or two of paint.

 

look at the control arm closely.... notice that the center bushing and mounting bolt are SOLID to the frame... they don't move or rotate.. The "arm" is allowed to move up and down when the rubber around the steel bushing "flex" and let the arm travel. You need no lube in the area... spray paint would be fine when all is clean.

 

Interesting. So the rubber bushings don't rotate? The arm moves on them but they only twist to some degree? I guess the notches are there to prevent the parts from rotating.
I wonder why it's like that. It seems like the bushings would wear out rather quickly by not rotating with the arm.