GM upper control arm cross shaft serrated washer

I'm rebuilding the front end on a 96 Impala. The upper control arm cross
shaft has a serration on the rear end of the shaft, that a serrated washer
fits on, then the bushing, which also has serrations in it.

Anyone know what the purpose of these serrations is? And, more
importantly, it is more "serrated" on one side than another - that is, it
will mesh tightly with the serrations of what it's next to- any idea which
side goes next to the shaft, and which side next to the bushing?
--
Lee K. Gleason N5ZMR
Control-G Consultants

"Lee K. Gleason" wrote:

> I'm rebuilding the front end on a 96 Impala. The upper control arm cross
> shaft has a serration on the rear end of the shaft, that a serrated washer
> fits on, then the bushing, which also has serrations in it.

You sure the washer goes on first?
Is this the retainer washer (as big as the bushing) that goes on just before
the nut, or something smaller?

> Anyone know what the purpose of these serrations is?

The "serrations" (teeth on the ends of the bushing's inner sleeve?) are to
keep the inner sleeve from turning on the shaft (and slowly cutting through it)
with suspension movement once everything is tightened down. Since the
bushing's outer sleeve is a press-fit in the control arm (and usually needs
special tools ro remove/replace), the only thing moving should be the rubber
flexing as the arm moves up and down.