Hey there.
I've been working on getting my CL1 Accord fixed up and back on the road after the clutch blew on it.
I'm up to the final stages now but am uncertain about my driver's side upper control arm.
Before sitting the hub onto the upper ball joint, the control arm moves quite freely up and down. Once I've tightened up the ball joint, it only has about 10mm play up and down.
However on the passengers side, the control arm moves freely and happily up and down whether it's been tightened or not.
I can't see where or if I've gone wrong with the drivers side. Anyone have some wisdom to share?

 

I suspect that the one that flops around after being tightened is probably shot. If it were me, I would simply throw a new set of upper control arms on, they are cheap and easy to install. It would give me the peace of mind. I replace mine every 75,000 miles or so, but that's me. Some people drive on them forever.

 

Your control arms may have gone bad

 

If you do replace them, replace both sides, not just one, otherwise it will probably feel a little odd while driving.