mopowers
Well-Known Member
Anyone have a photo of a distorted axle tube from a round u-bolt that was properly torqued?
Dang U-bolts!
- Thread starter mopower440
- Start date
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In a wrecking yard I used a 6 foot fence post as a cheater bar.
Professor Fate
Push the button, Max...
Hopefully coming off and not going on. LOL
I don't even think about it. melt em off. My machine shop makes em.
Be sure you get the type with the knurled flattened portion in the middle of the U
Without that you will crush the housing tube. Also the torque is 45 lbs not 100, not that feels about right.
Look in the FSM to verify the number but I'm 98% sure.
Some of the post in this thread say the flat thang aint necessary. I enjoy the idea that it is important but some disagree.
That's just not true. All I've ever used are round u-bolts and I've never crushed anything. Crushing the axle tubes comes from over torquing the nuts and nothing more. You're correct on the torque spec. It's only 45LBFT.
I have to wonder why ma-mopar went through the effort to do the flattening and the cross x if is not needed.
I'm tellin all yall...and for the last time cause I'm growing tired of repeating it for folks that obviously think I'm lying, but they used both styles through the years.
Do you think it maybe a performance application ? I have run into both too but have not paid attention to the application.
matthon
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Yeah, same guy with the photo of the exploded ball & trunion driveshaft joint.
I've had a few original cars with both, the reason for either not obvious.
dr dodge
Active Member
run a wire brush/die grinder over them first,run a tap (backwards) over them w/ plenty of lube next
repeat till tap spins up by hand
then clean lube, andput never seize on the threads well first (before breaking anything loose)
break loose by hand, tighten, clean, repeat
you will never break a u bolt,
or just split at the top w/ 4" grinder and drop in 5 min
all depends in the u bolts, how much replacements are, and your pocket book depth
repeat till tap spins up by hand
then clean lube, andput never seize on the threads well first (before breaking anything loose)
break loose by hand, tighten, clean, repeat
you will never break a u bolt,
or just split at the top w/ 4" grinder and drop in 5 min
all depends in the u bolts, how much replacements are, and your pocket book depth
dr dodge
Active Member
all u bolts are mild steel
distorted housings are an installer fail
the flat oem ones are weaker than solid bar
different torque specs for different products
don't torq a round ubolt to the factory specs, use the ubolt spec and never crush a tube
trailer ubolts of proper load rating are fine replacements
most people way over torque them.
the locator bolt and saddle plate do all the work
dr
I've been through many U bolts. Manufactures always say replace them with new. It made it easy on us. Just blow them off and shezam.
woked on
dr dodge
Active Member
wanna buy a bridge? lol, just kidding
The more likely scenario was they were rat a tatted to hell and back with an impact gun.
That right there is it in a nutshell. However, "whichever" u-bolts you use, the need to be torqued to the factory spec of 45LBFT. Here's why. If they are over torqued, they will pinch the leafs in a bind and they will not compress and rebound properly. It can render the rear suspension pretty much useless.
You forget about point load. Round u bolts exert all there clamping force over a very small area meaning the psi is greater. The flattened u bolts spread the load over a many times greater area meaning for the same force the psi is considerably lower.
I have a housing where you can see the shape of a round u bolt on the inside and outside of the housing. I'm sure it was over torqued too but if it had had the flattened section I doubt for the same torque it would have done that.
8 3/4 (stamped steel tubing)
Dana 60 (heavy wall tubing)
No mention of over torque in the Dana instructions
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dr dodge
Active Member
my old trash truck (5ton+) had the same bolts off and on so many times to change the overloads
it's mild steel, soft, forgiving, it has to be, it can be heated red hot, very little strength is gone
I made my own because a for 5 ton truck w/ 16-20" bolts was stupid $$$$
took a week, after workc 1/4 turn to cut, 1/4 to clear chip. figured in '92 i made $75/hr drinking beer at the vise when it was done
10" long on each side of a 1" mild steel rod/bar stock. then we heated it and bent it over a piece of pipe
people so over thinking stuff sometimes
harrisonm
Well-Known Member
I have never had a problem finding U bolts. Do you have a compressor? Maybe you could borrow a pneumatic impact gun. I have one with 750 ft lbs in reverse. It will either take them off or break them off. I would cut them off and use new U bolts. I agree with @RustyRatRod and others. No way I would reuse an old U bolt that is likely damaged.
dr dodge
Active Member
the flat is thinner, and has more stretch/give
torquing a round to the same value WILL distort the axle
the u bolt only needs a bit of stretch
as I said, never torque a round to the factory/flat spec
torquing a round to the same value WILL distort the axle
the u bolt only needs a bit of stretch
as I said, never torque a round to the factory/flat spec
Factory spec is 45LBFT. FORTY FIVE FOOT POUNDS. You ain't gonna distort a thing at that torque.
dr dodge
Active Member
the distortion could be not from the ubolt tightening
it was what the axle hit first. seem plenty of distorted axle housings stresses there
usually from the concrete 2 seconds before that was just minding it's own business
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