Axle shifted

[steveinville]

When returning home from a recent trip I could tell in my driver's side review mirror that the two tires were not tracking in the same line. Upon stopping it appears that one axle has shifted laterally. After searching on this forum, I read all that I can find about tightening u-bolts. But how do I get the axle shifted back where it should be, and realigned before I tighten?

[Exnavydiver]

You will probably have to take most of the weight off the axles. Leave rig hooked to truck, jack and safety stand both sides of the rig. Once you have the weight off the axles you should be able to re align them close enough to the original position to get it to an alignment shop. What most likely happened was when the U-bolts got loose you probably hit the brakes and it shifted. When it shifted it most likely snapped the spring alignment pin off the axle. This pin is only there to keep the springs in place until the U-bolts are tightened. If you can lift the springs high enough to see where the pin was you can position the springs properly. Then tighten the u-bolts evenly and torque them properly. If it was me I would run it over to an alignment shop to make sure everything is correct. You should probably check the tires closely because when out of alignment like that they tend to scrub the tread right off the tires. Richfaa had this very thing happen on the way to the fall rally... Dave

[steveinville]

Thanks for the feedback. What kind of "alignment shop" would likely work on such a thing? I am in the Dayton, Ohio area. Anyone know of a place?

[Exnavydiver]

One that does semi trailer alignments. There are several in the Dayton are I am sure.. Dave

[richfaa]

Had the very same problem several months ago on our 3400 on the way to the G.L Rally. U bolts came loose, sheared the center pin of the spring on the left side rear axle. Got it to a dealer in Michigan and they were able to repair it. It did ruin some tires and the cost was over 600.00 most of it covered by our Extended service contract. We had the OEM suspension cut off before the fall rally and had Mor Ryde install the IS system.

[blarkman]

You don't say what year or model. I would be sure looking at shackles and welds. We had this on our 99,2750 shackle hanger broke and back and front axles would rub when backing in.

[ljensen]

Check your bushings on your hangers,if they are gone your axles will be not alligned, they could be out as much as one inch. Install wet bolt kit if this is the problem.

[indy roadrunner]

steveiville
I work for a trucking company in the Fleet maintenance department. We re-build and repair our own trailers. If you have the ability to get the axles off the ground - alignment in not that complicated. Nor is it complicated to check. We have to do it every time we perform perventative maintenance on our trailers which is once a year. Here is the process. Drop a plumb bob from the center line of the king pin. Then use a strong string and measure back to the center line of the Left front axle on the outside of the hub. Take the same measurement to the right side of the front axle. Pefect alignment will be exactly the same measurement to either side. Once the front axle is aligned with equal distance to the king pin the measure from the outside center line of the front axle on the left side to the rear axle centerline. Now go to the right side and measure from the center line of the right front axle to the centerline of the right rear axle. You should have the same measurement for perfect alignment.

This measurement is not a bad thing for all trailer owners as over time axles will get out of alignment and it don't take much till you start wearing tires out.

[7.3Ford]

quote:Originally posted by ljensen

Check your bushings on your hangers,if they are gone your axles will be not alligned, they could be out as much as one inch. Install wet bolt kit if this is the problem.

I have seen reference to wet bolt kit in the past. Where do you get it?

[carlson]

Phil,
Thanks for the info on checking axles alignment.
Question?
With a 3400 RL and I "Drop a plumb bob from the center line of the king pin. Then use a strong string and measure back to the center line of the Left front axle on the outside of the hub"
The string hits the sidewall of the tire.
How do you extend out the point of the center line of the hub to get a accurate measurement?
Thanks
E. Sven

[Tom S.]

quote:Originally posted by carlson

Phil,
Thanks for the info on checking axles alignment.
Question?
With a 3400 RL and I "Drop a plumb bob from the center line of the king pin. Then use a strong string and measure back to the center line of the Left front axle on the outside of the hub"
The string hits the sidewall of the tire.
How do you extend out the point of the center line of the hub to get a accurate measurement?
Thanks
E. Sven

Actually, you may not need to. I'm going out on a limb here because I've not disassembled a trailer axle/spring connection, but I have done cars and trucks, and the axle/spring relationship is based on a pin that locates the spring and axle in the proper spot. If your axle shifted (for whatever reason) chances are the pin has been sheared off. The pin is not designed to hold the axle and spring in the proper location, it is only designed to locate them in the proper alignment. Once the spring and axle are aligned via the pin, the U-bolts are what holds everything together. In the most common type of pin arrangement, the pin is a round headed bolt or dowel that is mounted to the center of the spring, with the head of the bolt/dowel fitting into a corresponding hole in the axle or the axle mount. Replace the broken pin, line everything back up and tighten down the u-bolts and you should be good to go. It's fairly easy to do the job once the pin is replaced, but replacing the pin (especially on an older spring) can be a bit of a chore.

[mopar1]

After reading here about loose U-bolts I checked mine. They were loose! Re torqued them and checked them after our trip to Kentucky. They were still tight. Should they be checked often like the lug nuts?

[indy roadrunner]

e.sevn in response to your question there is about 3 different ways of taking the measurement. Drop a plumb bob from the king pin to the surface and make a mark. Now take back to the front left axle hub and drop the plumb bob and make a mark. Now jack up the left front axle and take your measurement. Repeat process on right side.
You can also remove the tire and take measurement with a small bend around brake drum. It needs to be the same on the right side. At our Fleet shop we have semi trailers and we use a large carpenter square to mark center line of axle on the floor. Jack axle and take measurement from king pin. That way we don't have to remove those dual tires if not necessary.

[Exnavydiver]

Mopar1, after my loose u-bolt episode last summer I check them once a month unless I am staying in one place for longer. So far I have found zero loosening of any u-bolt nut. Also no movement of axles. When I first checked them I found two nuts within 2 threads of FALLING OFF. All the rest were very loose. I tightened them all to just touching then tightened them to the proper torque in a X pattern so they each got the same torque evenly. Worked fine for me and I still check (just in case)... Dave

[KathyandDave]

I just learned something new, just like every other visit to the MOC. Thanks to all.