I believe that "old plate" you are referring to is actual an angled axle "caster" wedge that is required to set the axle position correctly.

It provides a specific degree tilt to your king pin and spindle positions so that steering and alignment function correctly. With out them, you truck is going to really be hard to drive (not to mention kinda unsafe).

Check you shop manual for more details about the wedge and reinstallation of your axle and steering components.

Dan

Last edited by Gdads51; 04/08/2023 11:20 PM.
~ Dan
1951 Chevy 3 window 3100
Follow this story in the DITY Gallery
"My Grandpa Carl's Truck and How it Became Mine"
1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver)
US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)