M101A2/A3 Trailer failure warning and PM recommendation

[Trailboss]

I’ve owned this M101A2 trailer about 12 years and have put an estimated 13-15 thousand miles on it, including a 4000+ mile trip to WY in 2020 and a 1300+ trip to TX in March. On a 1800 mile trip to the Denton Rally last month, my M101A2 trailer surge brake mounting bolts failed at around 830 miles.

The 4 bolts are labeled #13 bolts in the attached Figure 10 from the TM. The two ½-24 bolts closest to the pintle ring screw in upwards into nuts welded to the surge brake housing, and these had fallen completely out. The two rearward bolts had become loose and the tongue had dropped away from the front of the surge brake housing as can be seen in the photos.

With the help of other Rally attendees, I was able to re-tighten the rear pair of bolts, install one new ½-24 bolt in the front and had to use a smaller bolt and nut in the other hole because I couldn’t find a 1/2-inch grade 8 bolt locally. I also used a 3” ratchet strap to support the tongue, and the repairs lasted another 1050 miles until I could return home.

I recommend every owner check these 4 bolts at least annually, or every 500-1000 miles on trailers that are being used frequently.

 

[MarkM]

That could have gotten ugly real fast. Thanks for the tip and now I will take a look at mine.

Mark

 

[juanprado]

Years ago when I had replaced the shock and some of the nylon link bushings I had found some loose but not as bad as your situation. I would recommend you replace the nuts and install grade c or 8 prevailing locking torque nuts.

 

[gimpyrobb]

We have had this warning before. Some said they welded that seam as to not worry about bolts coming loose.

 

[Trailboss]

We have had this warning before. Some said they welded that seam as to not worry about bolts coming loose.

I did some searching before posting, but I'm old and my wife tells me I don't do anything as good as I used to.

I thought about finding a shop to tack weld the plates if my repairs didn't hold, but they are still solid. I may weld the plates if I can't put it back to original with new bolts and nuts.

 

[juanprado]

I did some searching before posting, but I'm old and my wife tells me I don't do anything as good as I used to.

I thought about finding a shop to tack weld the plates if my repairs didn't hold, but they are still solid. I may weld the plates if I can't put it back to original with new bolts and nuts.

We must have the same problem and wife. Who knew?

 

[Guyfang]

Her twin sister lives here with me.

 

[MarkM]

Use longer bolts and jam nut them. Or even more military get some proper bolts and safety wire them. No way to loosen then.

Mark

 

[MarkM]