Is there an alternative to soap for suspension bushing installation?

[papak]

The essential question is how the bushings function. Do they regulate suspension movement in shear or are they solely serving a cushioning function? If it is the latter, a high quality non-petroleum based grease should function well while also serving a corrosion resistant role as well. Thoughts?

[spacecad3t]

I use WD40 dry silicone spray, during install and every fall before winter.