Frame / Springs: differential-to-spring blocks; broken 'centering plug', critical?

[bsrosell]

Hi,
cleaning up the differential before taking it apart and cleaning INSIDE (replacing seals and axle bearings...), and took of the old springs yesterday.
The "blocks" that separate the leaf-springs from the differential "flat" (under the big U-bolts) came apart. Scared me at first, thought they had broken or something and maybe in for a new differential housing! But then tapped the opposite side and that popped off too.
BUT, (and sorry for the poor quality photos, I didn't look at them before I put my Iphone back in my pocket) the 'intact' one had nothing in the hole in the differential 'stand-off", just an open hole, and the lightweight spacer block (feels like aluminum or pot-metal, what's with THAT?) DID shear off at the mating surface.

Can't understand why that spacer isn't heavy duty steel or cast iron.... Would thing that would take a pretty good beating in that position. The whole car is resting on it! Regardless, any suggestions on 'building up" or replacing that 'plug' (looks like a very soft metal, maybe was an aluminum plug that went in at assembly?). It's only purpose seems to be to CENTER the two pieces until the U-bolts and spring get assembled and tighten everything together. Was debating about just JB-welding a bolt about that size in there, but since I'll only be doing it once before assembly, thought I'd check and see if I'm missing another purpose (or better way of doing this centering job). I would think the only critical thing here is to make sure those two pieces are in perfect alignment before getting all squeezed together by the U-bolts, but will be a lot of moving and "shearing" going on while getting that heavy spring in place and tightening them all back together; just needs to last until then.
No way those soft plugs held anything else all these years...
Thanks!
Barry

[junior]

at first look, they look like aftermarket lowering blocks to me. If they are indeed aftermarket, its easy to find replacements. The ones I've seen are cheap cast aluminum. cheers, junior

[11SecAvanti]

That looks like an aftermarket lowering block kit. Not factory IMO. Should not go back in.

[bsrosell]

Sweet! Thanks! Never thought to check, looks factory, but you're right, I can't find it in either the Frame or Differential exploded views.
(and the springs I took off had DEFINITELY been modified, had about a 6" 'loop' bent into them, etc...) and had mag wheels on it when I got it. Some kid making a jalopy at some point years ago (Crager mags on front, big gold alloy mags on back, electrical taped studs on BOTH drums that had the original left-hand threads; Can only guess how THOSE came loose at the tire shop :-)
Thanks again!!!!

[karterfred88]

Look like about 3" lowering block, definitely aftermarket. If your going back stock (after checking your springs for mods too) place them in you recycle bin, and go back to factory. There are many sources of replacements, if you need to put them back in for some reason, Jeggs, Speedway, Summit, and even your local Auto Store. Remember you'll need new short U-Bolts without them.