Welcome. Common issue with these trucks. Specially if in the "snow belt"
Take off the bed.
Replace rear shocks,
Support truck with jack stands,
Blast the leaf spring bolts with PB blaster let soak.
remove bolts.
Grind off rivets for the leaf spring hangers.
replace... link
http://shop.advanceautoparts.com/p/d...spring+shackle
the new hangers will come with bolts. Will take a while to grind them off and tap out the rivets. Not "hard" but a pain. I did all my leaf spring hangers. all 4 where next to god (full of holes or holey.....)
Some will tell you to drop the gas tank for the drivers front, i did not ....but prob should of....
some pics of mine during same procedure
You can see the bolts here
all done and painted
take a good look at the frame, they tend to rust the rail below the gas tank...
example:
As long as the frame is good, def worth fixing, and not that hard!!!
Get a good grinder NON of that harbor freight junk. i burned though 2 of those on this job before i got a good Dewalt. Never again for cheep tools
ALSO take a good look at your break lines. I replaced all mine when i purchased it, they where bad. Since you have the bed off why not?
if you have more questions feel free to ask, search and brows the site.
Also may want to make a signature to tell us the details of the truck, so when you ask a question you will not have to post every time what year make model engine etc.
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oh check your cross members too!