# Tow Behind Forklift



## whimik (Jun 11, 2013)

I am interested in the tow behinds that people are running and considering building one. Is the rear axle is solid mounted to the frame so there is no suspension?


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## HarryVanderpool (Apr 11, 2005)

How about we start from the beginning?
The first consideration is to start out with the right running gear.
You need to find a truck with manual locking hubs, not full time FWD, "all wheel drive" or any of that.
Ideally, a V8. If for no other good reason, so that you have enough counter weight.
Once you THINK that you have found the right truck to use as a platform, STOP!!!
There is one very important thing to investigate.
You have to positively find out where the oil pump is located for the transfer case.
The transfer case oil pump must be driven from the rear output shaft.
If it is driven from the front output shaft, keep looking.
Reason: When you tow the tow-able forklift, you will place the transfer case in neutral and have your hubs unlocked.
It will tow very light and easy in this mode.
When you are towing, the propeller shaft from the rear axle will be spinning into the transfer case and keep it lubricated.
If the transfer case has the pump on the wrong end, you will burn up the unit.
So there are a few thoughts for you to chew on while I look up some construction pictures I took of the finest tow-able forklift ever made.
Mine!


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## HarryVanderpool (Apr 11, 2005)

The second thing, and it is every bit as critical as the first is mast selection.
During the designing phase, (over one year) a friend of mine gave me a mast.









It was defiantly the correct size, but turned out to be an obsolete piece of junk. 
So I went shopping.
Where does one go in order to find a mast?
Are you ready for this?
Portland Oregon has 14 forklift wrecking yards!!!!!!









The one I really liked was off of a Hyster XM35.
It is a 3500lbs, two stage, full free lift mast with side shift.
It gives you a "clear view"
$650.00 complete.

You would be better off in my opinion to try to find a lighter capacity in a 3 stage, full free lift mast.
They are out there. Just make sure that there are parts available for what ever you choose.
Don't buy a mast that is too heavy. It will reduce your lift capacity and cause a lot of bounce on the highway.

I'll let you chew on all of that for now.
I'll leave you with this:
I spent one year designing my towable forklift after driving many variations on this theme.
Right off the bat, I told myself, "I am going to build ONE, it is going to be absolutely perfect, money is going to be no object."
And my design criteria was, " Hot-Rod / Forklift", a ballance of the two.
Love it!


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## whimik (Jun 11, 2013)

Thanks Harry. Your machine looks great, Do you know the wheelbase offhand on yours. I am starting off with an early bronco chassis which will be a bit narrower than yours. I am looking at putting in a 5.0l. I may shorten the wheelbase a bit but drive shaft angle with limit too much of that. I have been looking for a complete forklift I can just take what I need from it but most seem to be in that 4-5000 pound capacity.


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## HarryVanderpool (Apr 11, 2005)

4-5000lb mast is WAY, WAY to heavy.
Remember that your axles are the limiting factor on how much you can lift.
Every pound in machine is a pound you cannot lift without risk of bending or breaking an axle.
Also, you cannot go by the lift capacity of the lift truck that you are looking at.
You really have to look at the mast it' self. How much does that thing weigh?
For example, I have a Toyota warehouse forklift with a 3 stage full free lift mast.
Even though the lift capacity is only 2800 lbs, the mast is WAY, WAY too heavy to consider for your application.
Slow down and take all the time necessary to find THE RIGHT mast, of the right scale, with side shift.


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## HarryVanderpool (Apr 11, 2005)

Next step is to strip it down to the bare bones.
Everything goes except what you see here.

TAKE IT OFF!! TAKE IT OFF!!!









The next VERY important step is to determine just how short you can possibly make your rear drive line.
The shorter it is the shorter your wheelbase. And you want it as short as possible.
I was able to take this drive line down to about 10 inches, with about 1/2" of slide left for expansion contraction.
Since the axle will be solid mounted the only reason for slide in the shaft is for vibration or heat variation.
You should have no problem aiming the tail of the transfer case and the rear axle housing directly at each other.
Make sure to take time to get them pointed as straight as possible. Your U-joints will last for ever.


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## whimik (Jun 11, 2013)

You shortened that quite a bit. I should be able to do something similar. My chassis is already stripped down so just looking for a mast at the moment before i get ahead of myself. I had to look up free lift btw. Great pics they are a huge help.


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## HarryVanderpool (Apr 11, 2005)

When you remove the springs from your Ford rear axle you will find a mounting plate at the base.
Also, you will find a bracket welded to the axle.
Find a large grade 8 bolt and make a dowel that serves as a locating pin through the plate and into the bracket.
This will silence torque rotation of your axle.

Now that you have the drive line perfected, it is time to CAREFULLY locate the ideal position of the axle reletive to the frame.
The position takes into account the range of motion of your shortened drive line.
The axle must be positioned square and equidistant side to side.
The drive couplings MUST face each other.



















With everything perfect, weld the plate to the frame.
You will need to torch out 3- 5/16" plates per side to box the plate strongly in place.
Are we having fun yet?


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## HarryVanderpool (Apr 11, 2005)

DON'T GET IN A HURRY!!!

NO HALF-ASSING!!

SLOW DOWN!!!

Is this what you want your towable forklift to look like?:


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## whimik (Jun 11, 2013)

lol definitely looking to build a safe, reliable machine. I never thought of attaching the axle like that. Makes it easily irremovable if needed.


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## HarryVanderpool (Apr 11, 2005)

I am totally in agreement with your priorities:
1) Safety
2) Reliability
3) POWERFUL!
4) Ease of maintenance.


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## Grace&Mercy (Jun 26, 2015)

Awesome machine! I want more pics of your build. Especially steering valve and hydro system for mast.


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## HarryVanderpool (Apr 11, 2005)

Now its time to mount the mast.
This is probably the most dangerous part of the entire project.
Handling the mast, mounting it, and securing it against accidental movement has it's risks.
Don't take any chances. If you lose control of the mast it could smash you like a pancake.
Work safe and utilize every possible safety precaution.
Once the mast is mounted AND the tilt cylinders are attached, You can breathe easier.










Lets take another look at the mast.
And yet another good reason to shop around until you land on the best mast you can find; look at the mounts.
The mounts on this mast are ideal. They are designed with a half-shell kinda like crank shaft main bearing caps.
I called up Hyster and ordered new bushings and got the exact diameter of the shaft it would need to mount upon.










Next I went shopping for a length of DOM pipe
I ended up finding a length of 9/16" wall DOM pipe at a hydraulic cylinder shop of all places.
It was .050 to large in diameter.
So I had the ways turned down on a HUGE lathe!!
After wringing my hands for a couple of days, I bought another piece of DOM pipe and had collars turned in order to positively hold the mast in position. 
I just did not trust the .050" land to do the job.
Don't let the end caps fool you.
A buddy that works in the shop just HAD to cap the ends for some reason???!!

You are going to need all sorts of steel in all shapes and sizes.
A good place to look is at a local steel scrap yard if you just need a small amount of one thing.
Here in Salem, Oregon, we have a large metal recycling business that has a TREMENDOUS amount of dimensioned steel, aluminum, etc, all in very organized rows at a discount price.
Most of the steel that went into this project was bought new.
But several VERY EXPENSIVE dimensions of steel if purchased new in standard lengths were purchased in small remnants that saved me loads.


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## JSL (Sep 22, 2007)

You are a true craftsman Harry! I like the attention to detail.


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## johnbeejohn (Jun 30, 2013)

VIDEO WANT TO SEE IT IN ACTION THATS NICEEEE!!!!!! what did that cost to build if you dont mind me asking?


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## HarryVanderpool (Apr 11, 2005)

Thank you, Joe for the very kind words.
I always appreciate your posts and methodology!

John, I have $18,500.00 in my forklift
But remember, this was not a project on a tight budget.
I saved money where I could, but cut no corrers as you will see further along....


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## HarryVanderpool (Apr 11, 2005)

I am VERY sorry to say:
I did not take a picture of the mast mounting assembly, prior to installation.
But I will describe it and you can get the drift from the pictures of the mount, mounted.

I cut the mast mounting tube to the exact length that would allow it to be welded to two 1/2" x 6" x 24" inch plates.
The steel plates slid inside of the frame.
It fit very tight just as I wanted.
The unit was slid inside of the frame until the pipe was about 1/2" from the differential housing.
You want the mast AS CLOSE to the axle center line as possible.
Even 1 inch farther ahead of the axle requires a lot of additional counterweight when lifting extremely heavy items.
Your axle center line is your fulcrum. Take every reasonable measure possible to get the mast as close to the axle as possible.

Here is something to consider very carefully:
What is your level of expertise as a welder?
This part of the project, (as well as a few others) is such that you really need to be honest with yourself in answering that question.
And now we are back to the safety talk.
Whether you are driving doen the road with a family in a SUV following, or loading hives, triple stacked onto a semi, someone can get killed if your welds fail.

Welding the DOM tube to the 1/2" plates ran my mig welder at 100%
I ground a large bevel on the ends of the 9/16" tube for penetration.
Then I hauled off and SPRAYED the weld at full bore.
Then if you look closely at the mounted tube, you will see gussets welded radially around the tube to plate to absorb stresses when you are bouncing around in the field.
If you are a shade tree welder, that's O.K. there is alot you can do yourself when you build your own forklift.
Please be careful and get help with the high stress components that could hurt or kill your friends.

With the mast mount in position, the first thing I did was to plug-weld it into place.
In this case, plug welding is where you find holes on the outside surface of the frame and and weld through them, into the plate.
The frame that I had had lots of holes that allowed very good initial anchoring with plug welds.
With any automotive frame, you do not want to make full length welds on the web (the vertical surface) or you will most certainly fiind stress cracks later on.
Stitch welds, plug welds, and welding the end of the frame were my choices.










Again, THIS IS THE MOST DANGEROUS TASK!!!
What ever you do, however you do it, work safe. Get help.

And stop slobbering all over your key board over my sweet little warehouse forklift.
I payed $800.00 for it 12 years ago.
More on that later.....


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## liljake83 (Jul 2, 2013)

Ha ha I was looking at that picture thinking "Man thats a nice little forklift " then i read your coment below I started laughing out loud


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## B&E (Dec 27, 2011)

whimik said:


> I am interested in the tow behinds that people are running and considering building one. Is the rear axle is solid mounted to the frame so there is no suspension?


I know of one for sale in ON. PM me if you want the contact for the seller.


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## whimik (Jun 11, 2013)

Looking good all pretty straight forward so far. My welding skill is limited but I have a couple different local guys I use to weld the bigger critical components on heavy equipment. They have portable rigs and one also runs a small machine shop they are quite reasonable. We are currently building a double flail mower and they are modifying the rotors etc I am building the tow frame. 

Do you have an idea of what your mast weighs?


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## HarryVanderpool (Apr 11, 2005)

johnbeejohn said:


> VIDEO WANT TO SEE IT IN ACTION THATS NICEEEE!!!!!!












Sorry, no videos.
But if you use your imagination a little, maybe these photos will work.
Won't be long and we'll be loading trucks out again!


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## RAK (May 2, 2010)

Love the blue color. I bet its nice to have a machine that can lift 2 totes of syrup.


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## HarryVanderpool (Apr 11, 2005)

With all of the mast mount welding completed, the mast is now mounted.
>>>> PLEASE NOTE<<<<
Look carefully at the picture and you will see a chain hoist secured to the top of the mast.
This particular mast is weight biased forward.
Even in the position it is in, in the picture, it wants to fall forward.
You see that I have ratchet straps hanging on to it from behind.
You MUST have at least THREE securing solutions in effect at all times to secure the mast from sudden movement.

Your very next step is to attach your tilt cylinders.
Once your tilt cylinder mounting brackets are in place and the cylinders are attached, things are a lot safer in working around the project.
BE CAREFUL!!!

And now a word about hydraulic cylinders:
The shortest route to turning out a piece of junk is to decide that you are going to "just" use ag-cylinders that you pick up for cheap at the local tractor store.
When you buy your mast, buy MATCHING tilt cylinders that have tight, slip-fit pins.
My mast is from a Hyster XM-35 and I was able to get a pair of Hyster tilt cylinders from an XM-60
Why the larger cylinders?
Because they have a larger volume which means that the tilt function works slower and smoother.
Although they were used, THEY WERE NOT CHEAP!
I bought new pins from Hyster.
What is the result from all of this?
There is zero play. When you are driving across a bumpy field, it is as if the mast is welded solid into position.
No rocking and rolling and cerclank-cerclank cobbled up junk.
Cheapy AG-cylinders will give you very poor control over your precious load of bees compared to tilt cylinders, made to fit.

So that is the next task; mount the tilt cylinders.


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