What is correct Rear Axle Leaf Spring U-bolts length

[Mopar2488]

What is correct stock 8-3/4 Rear Axle Leaf Spring U-bolts length for 440 engine use 6 full spring leafs on left side and 5 leaves plus two 1/2 leafs forward of axle on right side. Is it 7-1/8" or 7-1/2"

 

[dadsbee]

I have the OE's from my Bee and my Dart ready to go into the blasting cabinet. They are both exactly the same yet the 340 Dart has 6 leaf springs and my Bee only had 5. I'll try to remember to drop one over the axle tube tomorrow on my SuperBird to see if it's are the same or longer and get you a measurement.

 

[themechanic]

I heard the factory ones have a flat on the side that contacts the axle housing to keep it from denting the housing when torqued down. Is that correct?

 

[dadsbee]

Yes, that is certainly correct.... the flatness anyhow. I'd say it's more so they don't move around. Axle housing side also has a XXXX pattern on it to bite in.

 

[Mopar2488]

Are they 7-1/8” or longer in length because don’t want to buy too short

Yes, that is certainly correct.... the flatness anyhow. I'd say it's more so they don't move around. Axle housing side also has a XXXX pattern on it to bite in.
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[Billccm]

Mancini has the correct U bolts that won't crush the axle tube.

 

[ruffcut]

Should be 7 inches, or there about. RUFFCUT

 

[Mopar2488]

Should be 7 inches, or there about. RUFFCUT

Thanks Ruffcut

 

[dadsbee]

So I'll skip post #2...

 

[Geetex]

Are they 7-1/8” or longer in length because don’t want to buy too short

Just a suggestion, since Wayne @dadsbee has been nice enough to offer to physically measure the length of the U-bolts for you why don't you hold off on buying, for the moment, until he gets you the measurement.

 

[Mopar2488]

I have 8” U-bolts right now, they are too long

 

[dadsbee]

What would help to guarantee someone gives you the correct answer would be a year and make.

That said, my Bee (5 leafs) and Dart (6 leafs both sides) are both 7 1/8" from top of saddle to thread end. '70 Plymouth Superbird, 440, Hemi suspension option coded... are about 3/8" longer.. so 7 1/2". Lots of extra thread hanging out but if you want them correct that is what they are. Leaves lots of thread if you want to add some quick tie down strap plates for trailering if that's in your future.

 

[Mopar2488]

1968 Charger

What would help to guarantee someone gives you the correct answer would be a year and make.

That said, my Bee (5 leafs) and Dart (6 leafs both sides) are both 7 1/8" from top of saddle to thread end. '70 Plymouth Superbird, 440, Hemi suspension option coded... are about 3/8" longer.. so 7 1/2". Lots of extra thread hanging out but if you want them correct that is what they are. Leaves lots of thread if you want to add some quick tie down strap plates for trailering if that's in your future.
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[dadsbee]

Well as you can see in the last picture either U bolt length will work just fine, all depends if you want it "correct" or simply functional. Not sure why Chrysler used all that extra thread on the 6 leaf B bodies. My Dart is OE factory with 6 leafs and it has the 7 1/8" U bolts. Bird the longer ones.

 

[69bfan]

From our research in providing the leaf spring rebuild kits, Chrysler used two different lengths. That being a 6 & 5/8 inch and a 7 & 1/8 inch variety. The factory part numbers are 1489 746 and 1489 747.

As Wayne pictures shows and his information shows, either will work. We use the longer U bolts in the kits for the cars equipped with the Dana / Hemi suspension option.

If correctness is a concern for you, the picture in post number 4 from Wayne shows the correct "flatter" area on the outer most radius and they also use the embossed "X" pattern to better grip the axle tubes. Another area of detail is the "taller" 1/2 x 20 nuts as shown third picture in post number 12.

 

[dadsbee]

^^^ YEP, against my better judgement I measured them from the top of the U which matched the OP's 7 1/8" or 7 1/2" choices from some unnamed vendor. Normally a bolt length would be measured from under the "head" and that would match your numbers at 6 5/8 and 7 1/8 Richard.

Nuts..

 

[themechanic]

Tall nuts, eh? I never thought about measuring my nuts until now.

 

[Geetex]

Tall nuts, eh? I never thought about measuring my nuts until now.

They're supposed to have a square divot in the side of them also, so check your nuts, if the divot's not there you can use a square punch and hammer to replicate them. If you need to see what the divot looks like dadsbee can probably take a close up picture of his nuts, after he sand blasts them of course.

 

[dadsbee]

I'm not putting my nuts anywhere near that nozzle !!