Anyone have the size (diameter and length) of the rear shackle bolts for the leaf springs? I think I'm going to go ahead and install the Calvert Split Mono Leafs this evening, and want to get some Grade 8 replacements on the way home. Also, is there a rubber bushing on the top bolt of the shackles? The one where they attach to the frame itself? I probably should have checked that before I left the house lol. Thank you for any help!
If you still are using the factory original rear shackles, the bolts are attached to one side of the shackle and are not removable. The bushings are 1" diameter with 1/2 hole, D4DZ-5781-A was the ford part number and same for both leaf eye and frame. I think the original shackles had 1/2" shank that was stepped down to 3/8-24 fine thread and locking stover nut. You can still purchase OEM type rear shackles from many Mustang supply houses or I think Melvin's or Scott Drake carries them, if yours are in rough shape. David picture below shows: original shackle, 1/2" shank is attached to one side of plate, stepped down to 3/8-24. heavy duty shackle I fabricated 25 years ago, uses 1/2" grade 8 fine thread and nylon locking nut. recently purchased Global West Suspension, Del-A-Lum bushing rear shackle kit.
The factory shackles are 'stepped' to prevent the shackles from being overtightened and ruining the bushings. The factory shackle plates are also dished to accept the convex outer ends of the bushings. Having the shackle bolts fixed to one shackle keeps both bolts parallel and limits the amount of twist in the whole assembly.
