Loose front axle on tandem trailer

BigYoung · Oct 19, 2015

I just bought a 1996 18 foot utility trailer with tandem 5200lb axles to haul my 8N, this is my first tandem axle trailer.

Backing into the driveway, I noticed the front tires move out of alignment with the rear tires and I understand this is normal.

Removed tires to repack bearings and inspect brakes and I see my front axle U Bolts are loose enough that the u bolts have rubbed a 1/2" wide mark on the rusty axle where all 4 u bolts ride. U bolt fine thread nuts are rusted tight so they didn't loosen. Has not cut a groove in the axle, just rubbed rust clean. Front axle Shackle straps and bolts are worn and will be replaced.

Are the front axle U bolts supposed to be loose to allow the axle to shift? or should they be big wrench tight?

All comments welcomed.

ramblineagle · Oct 19, 2015

The U bolts must be tight on all axels, remove u bolts and inspect spring center bolt and axels saddle if either are showing signs of wear replace both. Any good weld shop or trailer dealer should be able to replace the axel saddle.

caterpillar guy · Oct 20, 2015

Should be tight on the axle. You need the blue wrench to heat the nuts then tighten them up. The heat will break the rust loose for you. Or just cut the U-bolts off and replace. Your choice.

jon f mn · Oct 20, 2015

Cut off and replace those u-bolts. When they are off check to see if the centering bolt is still good, if not replace that too. I would also take the time to replace all the bolts and bushings in the suspension now too, if some is worn it's all worn. If you have a double eye type then replace the straps too.

showcrop · Oct 20, 2015

Once you have it done and have a good load on it don't be surprised to see some significant off-tracking between the two axles. The give within and between the components will still allow a significant amount.

BigYoung · Oct 20, 2015

Gents thanks for the guidance. Will tear into the second axle today. I expect to replace tires, shackles, bolts, ubolts and seals.

And will get the front axle ubolts torqued down.

jon f mn · Oct 20, 2015

All axle suspension bolts are one use captive bolts. They are designed to not turn, so if any of them
are loose and turn now then both the bolt and the piece they go through are shot. Also when taking them
appart you are best off to torch thenut off rather than try to loosen it because the bolts are knurled
on the head end and if you turn them when loosening then you have ruined the piece they go through. Also
you can't torch the bolt head because the knurling is too large to drive through. Most of the suspension
parts and springs have plastic bushings in them which should be available wherever you get your trailer
parts. Be careful with the new u-bolts as they are very soft so they strip before you over tighten them
enough to crush the axle, so you have to be careful when tightening.

jacksun65 · Nov 26, 2015

I have seen this happen before someone used lock washers on u bolts and they rusted and broke allowing them to loosen up.

BigYoung · Nov 27, 2015

(quoted from post at 04:38:11 11/27/15) I have seen this happen before someone used lock washers on u bolts and they rusted and broke allowing them to loosen up.

Thanks Jack, got the old trailer fixed up with new ubolts, shackle straps, bushings, springs and seals. Now I just have to replace wood deck.

Loose front axle on tandem trailer

BigYoung

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ramblineagle

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caterpillar guy

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jon f mn

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showcrop

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BigYoung

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jon f mn

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jacksun65

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BigYoung

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