In the process of installing a set of Detroit Speed 2" drop leaf springs in the back, appears to be the 1st time anyone has done anything to my '78 WS6. Installing Prothane spring buffers and shackle bushings, DSE shackles, new Calvert Racing 1/2" u-bolts (Grade 5?).
Driver side was discovery learning for me yesterday, cleaned and undercoated as I went, used new Grade 8 hardware. Got the leaf installed and the spring plate up, torqued the u-bolts to 65ft/lbs (based on Eaton Springs website and a post I found at NastyZ28 forums). But the spring plate was literally "U" shaped and left close to 1/2" gap between the plate and the upper spring mounts. Did the passenger side today and discovered the upper leaf buffer had to be trimmed down to fit the pocket upper pocket.
After trimming down 1/2 of the material, the buffer fit nicely into the pocket and the spring went in and spring plate went on. Torque to 65ft/lbs again, and despite the spring plate being up against the upper leaf mount, it was still "U" shaped and the u-bolts were splayed outward at the bottom. Decided to open up the driver side and trim the upper buffer, and the inboard u-bolt snapped off while removing the nuts. Other 3 nuts came off easily, but the spring plate remains "U" shaped. [Sorry, not smart enough to post pics, if someone will point me to a tutorial I will...]
1. WTF did I do wrong? Why did the plate stretch so much when reinstalling? Old steel that I should have replaced? Yeah, got that the urethane buffer pads don't compress like rubber ones. Did I waste my $$ on urethane buffers? Should I have used rubber?
2. WTF is wrong w/ Calvert 1/2" u-bolts? Or did I do something wrong? I'm not new to wrenching, been doing this for 25+ yrs (but on Harleys).
3. Recommendations on u-bolts and spring plates? I don't see a way around not replacing them...
So aggravated right now... this shouldn't be this difficult.