# Mounting Underbody boxes



## Flipper (Nov 1, 2001)

I need some advice on mounting aluminum underbody boxes on a F350 with a flatbed dump. Truck has a full sub frame for the hoist. I have 36" long boxes that will fit in front of the rear tire to the cab with room to spare. My problem is the front of the spring pack and hanger. The boxes have to go outside of this and I will still have room before I get to edge of bed. The problem is that puts the back of the box some 8"+ from the frame. I do not want to mount them to the underside of bed as it dumps.

I had the same setup on my old truck but they came mounted and I never looked at the mounting. I have seen the brackets for sale and I have a full shop so can weld up anything I need to. I just can't come up with a good strong way to mount them off the frame. Any ideas or photos?


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## leigh (Jan 2, 2009)

Not sure how the layout is on your truck but I actually drilled a hole in the back of box that lined up with the nut on the spring mount.I took off the nut and mounted box on the stud and put nut back on inside of the box.Used typical angle brackets set-up mounted to the dump-bed frame. Hard to picture,don't have pics,I've since sold truck.


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## vinnys (Mar 9, 2007)

*Box brackets*

Hope this helps. Made from 3/16 L angle and 3/8 Flat stock. No holes drilled in frame. They just clamp on around frame and used holes that were there to keep them in the same spot left and right.


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## vinnys (Mar 9, 2007)

*More pics*

Few more pictures. These are not under body boxes. They are narrower. These were ment to mount on bed rails.


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## Flipper (Nov 1, 2001)

Thank you both. I was considering both those options. Seeing those photos helped me a lot as well. Now when I get the boxes, I can mocked them up and measure out what I need. 

I am going with narrower boxes as well. I want them to be flush with the side of cab. I like how you integrated the mudflap. Looks good.


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## 02powerstroke (Nov 7, 2006)

I have my mud flaps set up like that to it helps keep the back window mud free if you have a little wheel spin while dumping.


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