[hatzie]

Originally Posted by 83GMCK2500

I spend the time to find the part number myself; one of our members, hatzie (I think) has a link in his signature to a lot of the parts manuals: http://gmpartswiki.com/ and I have a whole lot more success at the dealer if I walk up with the number in hand. Also, searching the part number on ebay generally yields good results too. For instance, from Parts Catalog P&A 51/51A for the 73-78 trucks it says that the striker bolt p/n is 9601750...there are 87 search results in ebay for that number. I see at least one where someone removed the plastic bushing from the bolt and is selling an incomplete assembly, there are also cheapy Dorman results in there, just gotta shop wisely.

Edit: You mentioned having three washers on yours, one is part of the assembly (pictured) and it's entirely possible they added the other two at the factory for alignment purposes. I'm sure Keith Seymore could confirm/correct my assumption. The actual hole in the body that the bolt passes through is much larger than the bolt, allowing you to raise, lower, shift in/out the striker for latch and door close alignment.

If you have the space and bandwidth you can download the parts books on the manual page.

What material is the GM striker bushing made from?
It sounds like the Dorman part is just not the right material. Too hard and brittle. Softer stuff like HDPE, Nylon or, Delrin might work fine. You can buy rounds of different plastic varieties in various diameters and bore the centre to fit the striker. I'd get a few types in the right OD and give em a shot.