u-bolt torque for 8K Landmark axles
- Thread starter oldelmer1
- Start date
Dennyha
Well-known member
I have what I believe to be an important consideration.
I have broken 3 center bolts on my tandem 7k axles' leaf springs. At the national rally, I discussed this with the representative with Dexter Axle. He was pretty emphatic that the only way there should be significant shear stresses on the center bolt is if the u-bolts are not sufficiently tightened. He showed me the specs for my 1/2 inch u-bolt, with flare nuts as being 70 ft-lbs. Since the rally, I've checked the u-bolts that I know were tightened to spec during my disc brake upgrade at the rally. With the weight of the camper sitting on the leaf springs, I was able to tighten each nut several turns to hit 70 ft-lbs. I believe the weight of the camper eliminates any gap between the leafs of the leaf spring, reducing the bolt/nut torque. Time will tell, but I'm hoping that since I've tightened each of the u-bolts with the full weight of the camper on the springs, I will not have any more issues with center bolts. Time will tell...
I have broken 3 center bolts on my tandem 7k axles' leaf springs. At the national rally, I discussed this with the representative with Dexter Axle. He was pretty emphatic that the only way there should be significant shear stresses on the center bolt is if the u-bolts are not sufficiently tightened. He showed me the specs for my 1/2 inch u-bolt, with flare nuts as being 70 ft-lbs. Since the rally, I've checked the u-bolts that I know were tightened to spec during my disc brake upgrade at the rally. With the weight of the camper sitting on the leaf springs, I was able to tighten each nut several turns to hit 70 ft-lbs. I believe the weight of the camper eliminates any gap between the leafs of the leaf spring, reducing the bolt/nut torque. Time will tell, but I'm hoping that since I've tightened each of the u-bolts with the full weight of the camper on the springs, I will not have any more issues with center bolts. Time will tell...
WillyBill
Well-known member
Your guess on camper weight is partly correct (sorry, no offense) but a bigger issue is that they take some road shock and miles to finish shaping to fit the axle tightly. I have found that if you hit them smartly around the bends and anywhere they are not laying on they axle tightly on the axle with a 3-4 lb hammer while rattling them with an impact gun they usually go tight and stay that way. (Weight of the unit on them at this time is a good thing) They will need to be checked after the first leg of your next trip and once more after a whole trip. Repeat if you found any loose the last time. I know, pounding with a hammer is unorthodox, but it really does accelerate the fitting of the bolts to the axle. They also stretch a bit and this helps get that done as well. And no, I've never had one break from doing this.
WB
oldelmer1
Well-known member
Dennyha
Well-known member
No. WillyBill's post.
oldelmer1
Well-known member
I just went out and torqued all the u-bolts to 85 lbs.
I have to admit, it took more turns than I expected to get to 85 lbs.
I did use a caliper on the u-bolt and of course, it measured between 1/2 and 9/16, hence the 85 lbs.
I chickened out for going to 95lbs.
Anyone go for 95 lbs on 8000 axles?
I have to admit, it took more turns than I expected to get to 85 lbs.
I did use a caliper on the u-bolt and of course, it measured between 1/2 and 9/16, hence the 85 lbs.
I chickened out for going to 95lbs.
Anyone go for 95 lbs on 8000 axles?
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