Well, I broke it.

[kerry]

What will the source of your new stronger frame?

 

[pugslyyy]

What will the source of your new stronger frame?

P G Adams, or at least that is the plan - I have the quotes but have yet to place the order. Probably Monday, had to line up how I was going to pay for it first.

 

[pugslyyy]

Given that the polyurethane compresses very little, especially if spread out over a large area, the thickness is not that critical. As I see it, the thickness is determined by the fixing method that will be used.
I went with 25mm x 50mm (1" x 2") bars of polyurethane, as this allowed me enough thickness and width for the counter-bore when using M10 bolts with a flat and spring washer. The head of the bolt is about 4mm (5/32") lower than the wear surface and there is about 10mm (3/8") under the washers, which I think is plenty.
With this setup the top of my subframe is 75mm (3") above the chassis at the front.

Thanks, good to know - for me the thickness is determined by the original spacing between the frame/subframe, as I don't want to disrupt that geometry just move away from the 3 point.

 

[dlh62c]

....just move away from the 3 point.

The Fuso FG not made for off road thread has some good points, no pun intended.

 

[pappawheely]

Sorry for your troubles but your experience has given me a wealth of information to use on my build. Many of the fears I had and ideas to overcome them have been verified. I know it's little consolation but thanks!

 

[pugslyyy]

Sorry for your troubles but your experience has given me a wealth of information to use on my build. Many of the fears I had and ideas to overcome them have been verified. I know it's little consolation but thanks!

Glad it's useful. Always better to borrow someone else's learning curve.

As long as you don't do a 3 point mount you should be fine.

 

[biggoolies]

Okay, Not wanting to hijack this thread but really is there other circumstances where a 3 point mount has broken a truck frame other than with this truck with its very heavy overloaded build with an extended frame? In my opinion, it is not the 3 point mount itself but a 3 point mount coupled with a extremely heavy load on an extended frame not designed for this load. Correct me if I am wrong please.

Glad it's useful. Always better to borrow someone else's learning curve.

As long as you don't do a 3 point mount you should be fine.

 

[GR8ADV]

I am not casting stones, pointing figures or any such nonsense. Just making an observation. And even then with limited knowledge.
.
Extending the frame and loading it up beyond the rear axle causes additional stress and strains in exactly the opposite direction of the strength of the design. When I first saw the crack, it looked very much like a fatigue fracture. However, I would have expected it at the top of the beam where the greater stress should have been. Now that it appears that the frame had been extended and the rear had been loaded, it make some sense.
.
Some folks don't grasp as well as they could the idea that vehicles are engineered to perform under calculated loading characteristics in both size and configuration. Assumptions are made by the designer regarding 'how' the truck is loaded and not just how 'much' the truck is loaded. Extending frames and adding load configurations ( and random fixes) with out engineering input can have real and unintended results.

 

[pugslyyy]

Okay, Not wanting to hijack this thread but really is there other circumstances where a 3 point mount has broken a truck frame other than with this truck with its very heavy overloaded build with an extended frame? In my opinion, it is not the 3 point mount itself but a 3 point mount coupled with a extremely heavy load on an extended frame not designed for this load. Correct me if I am wrong please.

Well you have to draw your own conclusions. Mine is don't use a pivot frame.

 

[pappawheely]

What I took away was to spread the load over the entire frame instead of concentrating it in a couple of points. My thought is to have the box rest along the entire length of the frame but allow it to drop away when the frame flexes. Use the pivot but increase the amount of pads used to support the weight. I was thinking that the spring mounted bolts would articulate better if they were heims allowing them to rotate as the frame flexes. I would create a drawing to demonstrate my idea but my Solidworks crashed.:mixed-smiley-030:

 

[biggoolies]

Well here comes out my thoughts...

Frame extended, too much weight too far back. Past what the frame was designed for. Frame breaks. Frame gets fixed with a heavier duty frame that no longer is designed to flex like original. Fixed? No. The lack of flex on the rear frame is now transferred to the frame that still flexes in front. Another break. Perhaps that frame was damaged months ago and the compounded stress has finally made it snap due to the transfer of forces.

Okay now what I would do...
Doug is brilliant. I have seen his build. Actually the systems he put into the truck and how they are organized reminds me of the space shuttle. I just can't believe that someone single handed could create something like this. But I think having that motorcycle garage perhaps wasn't a good idea. Could camper be positioned over the cab over. Perhaps perhaps not. Would that have created a high center of gravity to allow the cab over to rotate open which would have too much twisting force with the extreme weight and destroyed the frame anyhow? Doug must have been an engineer from what I have seen from the systems he created. You see, I think over the long term this repair you did perhaps is a temporary measure and something else will snap.
Okay NOW what I would do. I would either fix the frame up front and move that camper forward if possible or...
Take that space shuttle off the back of the truck and give up on the fuso. Sell it for what you can get out of it. Find a Ford f450/F550 7.2l truck and put that space shuttle on the back of it. Hmm like an Earthroamer.
We all feel bad this happened to you but you got this amazing truck for a steal broken frame or not. I wish the best for you in this and hopefully this info will help you in someway. I don't know. Put it on a Ford f450/f550. Or course, this all takes cash and time or lots of cash. I don't want to discredit Doug in all of this. He is simply brilliant and someone I highly admire and respect like the rest of us.

 

[k9lestat]

I was wondering, from picts is saw,what if you reversed the three points? Meaning the single point up front and the two in the rear. The center of the frames seems to be where it would twist the most. Seems like would allow you subframe to twist with less resistance or tension.

Sent from my QMV7A using Tapatalk

 

[dlh62c]

Glad it's useful. Always better to borrow someone else's learning curve.

As long as you don't do a 3 point mount you should be fine.

You definitely have my respect. I doubt I would have had the courage to share all the details in a public forum.

Can PG Adams build a thicker frame rail?

Do you plan to use the same camper body?

 

[pugslyyy]

You definitely have my respect. I doubt I would have had the courage to share all the details in a public forum.

Can PG Adams build a thicker frame rail?

Do you plan to use the same camper body?

Yes, the only thing I plan on changing is the frame.

The Fuso frame is marginal for 14,050 pounds - I've seen discussion that they didn't change the frame when they went from 12,000 GVWR to 14,050. They use a fairly cheap and light steel that is only 4mm thick. The new frame willl be 1/4" thick and a Grade 80 high strength / low alloy steel.

Interestingly enough, one of the example replacement frames on the PG Adams website is one they did for a Fuso FG.

 

[SkiFreak]

Do PG Adams dip their chassis rails in an anti corrosive bath? It would be a definite positive if they were able to do this, as rust is one thing that kills a chassis.