I'm currently driving accross Mexico with my '78 GMC Vandura 1500 Rally.

Those who have driven in that beautiful country are familiar with the numerous speed bumps present EVERYWHERE. Of course sometimes I unfortunately miss seeing one coming and hit it full speed.

Now I think I hit one too many. The rear suspension, which I think had already started clunking, seems to be problematic. Everytime I roll over a bump the rear will bump up and down like something in the suspension hardly absorbs it.

How can I know if the problem is related to the suspension arm or the leaf springs?

I notice the leaf springs were attached with metal rings (similar to ones you would circle around a plumber tube) and those broke off over time. No layers in the leaf springs seem to be untended though.

 

sounds like you blew out a shock. if it was a spring it would sit lopsided or sag.