FJ - Car Hauler Trailer Warning

[FreighTer Jim]

For the past several months I have pulling an
all aluminum custom built enclosed car
hauler trailer on a dally basis.

This warning applies to all trailers

Check your axle mounting plates

On my tandem 5200 pound torsion axle
trailer - the passenger mounting plate
on the front axle completely broke
and separated the axle from the trailer:

743C4D25-7E31-4629-B1E4-4C1110FFE69F.jpeg (99.48 KiB) Viewed 4080 times

This happened in a two hour span
over 100 miles without any noticeable
prior warning signs - although the axle
plate probably was cracking for awhile.

Prior to this - I didn’t consider axle mounting
plates a necessary inspection item for
trailer maintenance - but now I do.

The axle plates are aluminum and are
welded to the aluminum square tube
frame - but this can happen with steel
axle plates as well.

If you own a trailer - check each axle plate
to make sure they are not cracking ….


FJ

[TWrenn]

Thanks Jim. Will do! I'll be putting the '13 in it and then both in the barn for the winter, so I can crawl around on a (relatively) clean cement floor with lighting to do a better job than I can outdoors on the gravel parking spot.

[TXGOAT2]

Aluminum was once called "The trouble metal".

[Craig Leach]

Hi Jim,
Having spent decades working on aluminum tankers, semi & pull trailers, fire truck cabs & body's I have found many designs, material
selections and welds that fell short of there performance expectations. I'm thinking you have fell victim of at least two of those items.
I'm hoping there was not to much damage to your trailer when that happened. I hope you found someone with better engineering &
welding skills than the manufacture of the trailer had to repair that. Our trailers go more miles and faster than our T's do so we should
be more attentive to them. Maybe we should have a trailer safety check list and inspection just like we do for our T's before every tour
right, right?
Craig.

[FreighTer Jim]

I spent a few hours today chasing down
material - prepping the trailer for the
certified welder who is coming tomorrow
morning to do repairs.

The trailer manufacturer did not use
stock aluminum angle - they either
rolled 1/4 “ stock or welded two
flat pieces together to make the
90 degree angle …

After repairing the broken mounting plate
the remaining three aluminum torsion
axle plates will be inspected - repaired
and reinforced.

I just took a video of the axle and
posted it on YouTube:

@ https://youtu.be/OPqG1SsZeBs


FJ

[FreighTer Jim]

Waiting on the welder ….

FJ

[NHUSA]

Jim, there is a guy on the Model A club forum looking for you. He needs a 20 ft boat and trailer moved from NC to MI.
I sent him here.

[FreighTer Jim]

Jim, there is a guy on the Model A club forum looking for you. He needs a 20 ft boat and trailer moved from NC to MI.
I sent him here.

Thanks but I don’t tow other trailers.
My insurance doesn’t cover it.
Aside from that - I would be foolish
to take responsibility for towing
equipment that I don’t know the
condition of ….


FJ

[otrcman]

Not saying that aluminum is a bad idea for a trailer, but there really are a bunch of special considerations when using aluminum as a structural material. I could simplify it all by saying that aluminum is far, far weaker than steel in this application. But for those more technically minded here are some considerations:

(1) Aluminum is 1/3 the weight of steel for a given part size, but it is also only about 1/3 as strong as steel.

(2) Fatigue - When we put a load on a piece of material one time, it will exhibit a given strength. If we repeatedly load and unload the member, the allowable strength goes down. Especially if the repeated load continues for a long time and the vibratory load is anywhere near the maximum one-time strength of the metal.

(3) Welding degrades the strength of any material. With steel, the degradation isn’t too great. But aluminum degrades significantly when welded and there’s no good way to heat treat a welded aluminum. Worse yet, only certain aluminum alloys lend themselves to welding. And those certain weldable alloys are among the weakest and least heat treatable alloys.

So what we have in a welded trailer is a structure that has a lot of factors against it, and all of them are more difficult when the structure is aluminum. I’m not saying that an aluminum trailer is a bad idea; it just requires a lot more care in its design and fabrication. After all, airplanes are built largely out of aluminum But they’re hideously expensive to design and construct.

Now to the numbers:

Weight: We already know that aluminum is only 1/3 the weight of steel, and only about 1/3 as strong.

Fatigue: That’s the repeated pounding that any trailer gets when going down the road. In the lifespan of a trailer, the jolts add up into the millions. That’s a lot of fatigue. So the aluminum weld joints need to be be about 3 times as thick as the non-welded areas.

Welding: Weldable aluminum alloys are generally about 1/4 as strong in the welded areas compared to the areas that are not welded.

Taken all together, a welded aluminum structure AT THE WELD JOINTS is only about 1/10 the strength of the native material. That doesn’t mean the entire trailer has to be ten times as thick; just the welded areas that are subject to fatigue. This means a lot more care in the design of the trailer. Properly designed, an aluminum trailer has lots of advantages.

[FreighTer Jim]

Later today my welder John will do
a detailed interview of what he found
and why the aluminum mounting plate
broke at the corner from the aluminum frame.

I will post a link here when I
upload the video to YouTube.

FJ

[FreighTer Jim]

I would not advise that you buy any trailer
manufactured by Middlebury Trailers located
in Middlebury, Indiana …

Here Is Why:

@ https://youtu.be/V_-MhHJkysU


FJ

[Luke]

I would not advise that you buy any trailer
manufactured by Middlebury Trailers located
in Middlebury, Indiana …

FJ,

You were pretty scathing of the design in your video. I can quite understand the shock and disappointment at what happened, but I was wondering if you'd contacted the manufacturer to let them know about the issue?

If there are issues with the original design that only occur after a large number of cycles, and given the miles you're likely to be doing compared to many others, it would be good for the manufacturer to know about this. They may then be able to contact other purchasers of the trailer and give them an inspection and remediation process.

To my mind it would be the manufacturer's response to your information that would determine my view going forward. In many industries it's not unusual for a design to exhibit certain issues after some length of operating time, and for various fixes to result from that. If the manufacturer is responsive and responsible when alerted to this then to my mind that would go a long way towards addressing any perceived poor design, but first they need to know about it...

Luke.

[FreighTer Jim]

For a trailer manufacturer to install
a critical structure element
like an aluminum axle mounting plate
made out of lightweight aluminum
that was rolled to make a 90 degree
angle ….

Instead of installing the correct
fabricated structural material ….

Results in what you see on the video(s)
I posted - this trailer has less than 50,000
total miles of use - I am the second owner
and that mileage includes what the previous
owner put on it.

There is no way I would look to the
trailer manufacturer for corrective
action or trust their repair(s).

I am frankly tired of “ Crapmanship “

FJ

[otrcman]

Jim, Glad to hear that you are getting your trailer back to being roadworthy. I would caution, however, that you are still vulnerable to repeat failures in that same area.

6061 aluminum can be about twice as strong as 3003. But you should be aware that the superior strength of 6061 alloy depends entirely on the level of heat treat that the stock was subjected to when it was made. The problem is that the heating due to welding takes away nearly all of the prior heat treat. And then you're not much stronger than the original part.

The only practical way to preserve the heat treat is to not weld on it. That's why airplanes don't have any welded aluminum structural joints. Heat treated components are generally bolted or riveted together. For long term use, I would suggest that you replace the axle brackets with properly bolted-on steel parts. The fatigue life of steel is vastly superior.

[Luke]

FJ,

I won't dwell on this, but lightly comment that if one was to take the same path with regard to aircraft for example there would either be no Airbus, Boeing, or Douglas, or they'd all be falling out out of the sky regularly.

Each of these manufacturers has had severe incidents or accidents due to a design flaw in their aircraft, but because the issues have been reported to, and investigated and addressed by the manufacturer, the machines have been improved and are generally more reliable and less risky than before.

I think one could also argue that certain aspects of the Model T were found to be wanting, and were addressed in later vehicles to the general betterment of everyone. However if Ford had not made aware of these issues I wonder if such advancement would have been made?

Otherwise I very much agree with Dick.

Luke.

[FreighTer Jim]

Left side of front passenger side aluminum
axle mounting plate that broke off after
my certified welder John repaired
it & reinforced it to the frame:

Right side of front passenger side aluminum
axle mounting plate that broke off after
my certified welder John repaired
it & reinforced it to the frame:

The other three plates had cracks repaired
and were reinforced in a similar manner
by my certified welder John:

FJ

[otrcman]

Looks like a good repair, Jim. Puts the load through the welds in shear rather than in bending. That's as good as possible given the all-aluminum construction.

I'd still keep the joint on my inspection list, but I'm confident that it will significantly outlast the original design. And the welds themselves appear to be good quality.

Dick