M931 piggyback recovery from Camp Shelby

[mcshooter79]

Just wanted to share my recent experience with recovering the two 931s that I won in October. I wasn't sure if either truck ran and the auction said that the vehicles had to be towed or wrecked from the sight so I drove the deuce with a tow bar a plan and tools in hand. First I live in St Petersburg FL and aside from one front tire separating and throwing some tread (which I changed with the spare) my trusty low time ex Air Force M35A2 performed perfectly over 1400 miles. I had no intention on flat towing a 5 ton very far with the deuce but it was just a contingency in case all else failed and I simply had to get them moved a short distance until a better plan could be formulated. So my plan was to cross my fingers that at least one of the 931 could be made to run and drive and I would use it to get the other the rest of the way home. I also own a house right outside of Ft Rucker in AL so if I had to I could hold up there if making the trip all of the way to St Pete became UN-feasible.

I knew that one tractor truck could piggy back on the fifth wheel of another tractor truck with the right equipment. After doing some research I decided that the commercial equipment for performing this procedure would not work with the front axles of the 939 series trucks (or any front drive axle for that matter). So I thought I could just make some sort of tire cradle like the wheel lift tow trucks use and make it lock into the fifth wheel. So that's what I set out to build. I tried to think of all of the possible hangups (and of course many were found after the fact) and design it in such a way that the truck could be secured to the assembly without the front axle rotating and causing the fifth wheel plate to rock back every time I accelerated and forward every time I stopped. In thee end I tried to think of every way the truck could be secured to the device and incorporated a number of places that chains could be attached in hopes that even if the original plan failed something could be made to work.

After about $700 in steel, gas, welding wire, grinding and cutting wheels and a sunburn on my left arm (one day I will start wearing long sleeves when I weld) I had it built. I of course also had to tackle the problem of getting the truck onto the piggy back device, as I started calling it, so I built some 8 foot long ramps from heavy angle iron. At this point I was running out of time so my fabricating was becoming less elegant, but I figured I could make it work. In the end the ramps really should have been 10 feet long but I was afraid that if I made them any longer than 8 feet that they would become significantly more difficult to transport. The ramps weigh about 125 lbs each.

After a long but mostly uneventful drive from St Pete with a buddy of mine (with the one exception of the front tire on the deuce)we arrived at Camp Shelby. At this point let me say that if it were not for the assistance of Jeff Davis (http://www.steelsoldiers.com/member.php?13587-Csm-Davis) I'm not sure this recovery would have happened. The yard at Camp Shelby was actually only open for a few hours on Tuesday, Wednesday, and Thursday and since those days were just not possible for me it was Jeff who managed to get me into the lot on Friday. After the usual pains of tracking the trucks down, moving other trucks out of the way and finding a way to get a jump start (all effectively done entirely by Jeff and his assistant) I had two running trucks.

With fortune smiling but daylight running out I set about loading one truck onto the other. With Jeff's help we positioned both trucks in such a way as for the terrain to give us a slight advantage by placing the first truck slightly down hill from the towed truck. We set up the ramps and after a few tries the second truck was driven up the ramps and dropped right in place into the piggyback device. Now let me say that all of this stuff is of course heavy and after a long night of driving, and a day of wrestling big heavy metal things I was exhausted and all the more grateful to have Jeff's help.

My original plan for how to attach the chains quickly went out the window and after trial and error I found an arrangement that I was happy with long enough to get the trucks off post any way. This is also the point where I learned about the two different types of air valves in use with one type having to be oriented across the line to be open (strange to me) and the other type being positioned inline with the line to be open (what I always assumed was correct). Then the first time I tried to pull out the towed truck inexplicably kept locking the tires on me until I realized that the front axle was engaged on the towed truck and with the front tires being unable to turn the rear tires were also unable to turn. Yes the transfer case was in Neutral and after getting the trucks off post I did remove both rear drive shafts which if I had done in the first place would have avoided this problem anyway.

I will say that I though I build the piggy back device heavy but it bowed much more than I expected and did make me slightly anxious. After a nights rest at a local hotel I re-chained the truck in a way more to my liking, removed both rear drive shafts and I was ready for the road. I went by Jeff's place before heading out and he gave me a good price on some parts I needed and wished me a safe trip home. The trip home was actually mostly unremarkable. On level ground the 931 would actually outpace the deuce and would have held 60 mph if I had wanted. The driven truck was a 931 and the towed truck was a 931A1. I got about 4.5 MPG on the way home with the 931. there were a few hills where I slowed down in the 30 MPH range and coming out of the tunnel east bound on I-10 in Mobile I was down in the 20 MPH range at one point. The ride was stable and the piggyback device held up well. I will admit that I should have had a plan for lights on the towed truck and I did not so I simply mitigated this by driving at night as little as possible and have the deuce (driven by my buddy) act as rear guard the whole time.

Anyway to wrap a long and probably boring story all 3 trucks made the journey safely back to Florida.

 

[RAYZER]

Amazing!! Glad you made it back safe!

 

[andy3]

Gulp! That's a recovery!

 

[NDT]

There's a job waiting for you at Ibis Tek.

 

[mcshooter79]

LOL.....That's funny. I kind of need a job......................that's not as funny

 

[RAYZER]

Do you have a pic of the ramp setup?

 

[patracy]

Wouldn't it have been cheaper/easier to just use the towbar setup?

 

[Recovry4x4]

I've been known to do a piggyback or 2. My device used a fork design to fit right onto the square diff housing. Mine was all designed for deuce use! See avatar!

PS, my big trip was a little longer than yours, 2568 miles!

 

[rosco]

Congtatulations! Great adventure,

I see what you mean by the cradle sagging. I would have thought that something like 2x6 would have been minimum. Yes, a pic of the ramps would be great.

 

[M35A2-AZ]

Glad you made it home ok. Nice fab work.
Road trip are always fun, right?

 

[mcshooter79]

The ramps were a fairly simple design. I have been working everyday and by the time I get home it's too dark to take pictures but as soon as I get a chance I will post some more. As for the tow bar, I believe that the tow pintle is only rated for 10,000 lbs and the trucks weigh over 20 so that was one reason, also I generally don't like to flat tow, it's harder to turn and I worried about the towed truck tending to push the towing truck every time I turned or braked where it is generally more stable when the towed truck acts like a trailer and puts weight on the rear tires of the towing truck.

 

[patracy]

The ramps were a fairly simple design. I have been working everyday and by the time I get home it's too dark to take pictures but as soon as I get a chance I will post some more. As for the tow bar, I believe that the tow pintle is only rated for 10,000 lbs and the trucks weigh over 20 so that was one reason, also I generally don't like to flat tow, it's harder to turn and I worried about the towed truck tending to push the towing truck every time I turned or braked where it is generally more stable when the towed truck acts like a trailer and puts weight on the rear tires of the towing truck.

You're a little low on that pintle weight rating.

 

[zebedee]

... and $700 is way cheaper than a trailer too!

Was the 5th wheel plate a new purchase (and if so, where from) or did you have one kicking around in the yard?

Would the ramps be stowable on the 931 - so you could use it without the Deuce for other collections?

Nice simple solution.

 

[M35A2-AZ]

I was thinking the pintle was rated around 35,000 lbs.

 

[mcshooter79]

I think your right patracy but after looking it up in the TM it still says that the max pintle load for a 931 is 15,000 lbs..... maybe that is an off road rating?

Yeah $700 is way cheaper than any trailer I could find and while it wasn't as easy to load and secure it weighed allot less too.

Yes the ramps are easy enough to strap down and as you can see from the pictures here they are currently strapped to the piggyback device.

I also included pictures of the two "tractor" batteries that I bought as factory "blemish" batteries from my local Interstate Battery store for $100 each to replace the 4 dead ones in one of the trucks. The new batteries work like a champ.

And the square tubing is 2 1/2" tubing with 1/4" wall. Once I get it straightened back out and if I use it again I plan to reinforce it so that hopefully next time it wont bow/bend. I wanted to refine it more anyway, I just ran out of time. I would like to add some more material to the inside of the wheel cradle to better "cradle" the tire instead of just the 90 degree corner of the tubing. I think I could also add a piece of heavy angle iron, similar to what I used to make the ramps, along the entire width of the device along the top of the front tubing that would better cradle the tire and stiffen the the entire device. confusing? I can see it in my head and that's what's important right?....

I would also like to make an extension coming off the back with some form of releasable attachment for the ramps. With the tires squatted down in the cradle there actually was very little uncovered tubing for me to set the edge of the ramps on.

Oh and the fifth wheel plate was fabricated out of two pieces of 12x28" 3/8" plate steel with a store bought king pin welded into the middle. The plate was then welded flush with the bottom of the square tubing surrounding it so that the tubing added to the surface area of the plate.