Front Axle doing the "Fats Domino".
04-17-2010, 05:11 PM
#1
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Front Axle doing the "Fats Domino".
I have new u-bolts on my front axle, but it is still shifting back on the drivers side. Is it just a matter of cranking those bolts down harder than my Chinese air impact can get them? Also, do the springs just set on top of the axle or is something supposed to be in between?
04-17-2010, 05:35 PM
#4
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Yea, it stinks Brandon. Tears up tires, goes down the road dog-legged, and clunks. I think I'm just not getting it tight enough. Looking in the FSM for the torque specs.
04-17-2010, 05:36 PM
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x3 on the dowel pin! And those u bolts have to torque down to a certain spec. I think they are designed to strectch a little. Last time I installed a lift I the instructions required doing the torque three different times to make sure you got all the slack out.
04-17-2010, 06:07 PM
#7
Its called a spring center pin. It may have snapped. It happens sometimes if the u bolts are loose. It can move back and pop them off. It holds the spring pack together when the u bolts are removed also.
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04-17-2010, 06:58 PM
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Yup, a centering pin. Most lift shops should carry them and some Oreilly's have them too. At Oreilly's you'll have to ask because they will be in the back in a box.
04-17-2010, 07:04 PM
#9
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Is that the same as the bolt head on the long bolt that hold the spring pack together?
Also, the spring isn't necessarily moving around, the axle is actually twisting and sticking that way. I can tell because my steering wheel is no longer centered. I tighted the new bolts as hard as my impact wrench would get them, but I did not torque them to spec..
Also, the spring isn't necessarily moving around, the axle is actually twisting and sticking that way. I can tell because my steering wheel is no longer centered. I tighted the new bolts as hard as my impact wrench would get them, but I did not torque them to spec..
04-17-2010, 08:47 PM
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An impact will not put enough torque to your u-bolts. You have to at least cheater bar it.
I would take the u bolts off and clean them good. With a jack under that side of the axle, let it down and check the leaf spring centering pin. The spring pack should stay together if the head hasn't sheared off. Check the hole on the axle spring pad for wear too. I've seen them hogged out.
Napa sells all the center pins you would ever need if yours is broken.
I've also seen the front leaf spring bushing worn out and causing what you're describing as well. Might wanna take a look at it too.
I would take the u bolts off and clean them good. With a jack under that side of the axle, let it down and check the leaf spring centering pin. The spring pack should stay together if the head hasn't sheared off. Check the hole on the axle spring pad for wear too. I've seen them hogged out.
Napa sells all the center pins you would ever need if yours is broken.
I've also seen the front leaf spring bushing worn out and causing what you're describing as well. Might wanna take a look at it too.
04-18-2010, 07:58 AM
#14
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When I have install lift kits, the number that comes to mind for U-bolt torque is 150 ft. lbs. Even with a good impact you will not even be close to that spec. Just take your time and tighten each one evenly. Go in several steps to get to that number. They also tell you to recheck the torque a couple of times in the first thousand miles.
HTH
HTH
04-18-2010, 09:13 AM
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Section 2 page 78 of the 1992 Dodge truck Chrysler published service manual states:
TORQUE SPECIFICATIONS
FRONT SUSPENSION COMPONENTS 4 WHEEL DRIVE
SPRING U-BOLT/STUD NUTS (MODEL 60).........129N-m (95 FT. LBS)
The center bolt in the spring has an exposed head diameter in the 3/8" size range. The front housing hole that the center bolt set in on the perches is roughly 1/2" in size. It is not designed as a size for size fit.
Two rules on U-bolts that should always be followed whenever possible.
1. Never reuse a set of old u-bolts on an on road vehicle. They are relatively cheap as far as replacement cost go.
2. Excessive over torquing can result in decreasing the remaining draw strength remaining in the bolt. As you continue over torquing the nut the diameter of the bolt decreases and the threads that are being pulled in under the nut have a decreased amount of load contact area. This is one of the reasons nuts strip on bolts. The u-bolts are not made of a super high grade of steel. Have a conversation with your local spring shop as I did and I'm sure they can explain this to you as they did for me.
TORQUE SPECIFICATIONS
FRONT SUSPENSION COMPONENTS 4 WHEEL DRIVE
SPRING U-BOLT/STUD NUTS (MODEL 60).........129N-m (95 FT. LBS)
The center bolt in the spring has an exposed head diameter in the 3/8" size range. The front housing hole that the center bolt set in on the perches is roughly 1/2" in size. It is not designed as a size for size fit.
Two rules on U-bolts that should always be followed whenever possible.
1. Never reuse a set of old u-bolts on an on road vehicle. They are relatively cheap as far as replacement cost go.
2. Excessive over torquing can result in decreasing the remaining draw strength remaining in the bolt. As you continue over torquing the nut the diameter of the bolt decreases and the threads that are being pulled in under the nut have a decreased amount of load contact area. This is one of the reasons nuts strip on bolts. The u-bolts are not made of a super high grade of steel. Have a conversation with your local spring shop as I did and I'm sure they can explain this to you as they did for me.