72 4x4 parts help

[71 super]

I have a SWB 4x4 that is in dire need of replacement parts. The U-bolts that hold the spring pack to the rear end housing are rough at best as are the spacers?? that sit on top of the spring pack (look like camel humps that locate the u bolts) and the cross member is in front of the shock brackets. Is there any vender or other source that has any of these parts- save the crossmember- can the cross member from a 2wd leaf truck or blazer piece be used to replace the original one? Thanks for any help.