Overdue for an update I am sure. The box is back off the truck and on the welding table, and the lower parts are finish welded. No pics of that because it's boring.
One of my goals for this box was to integrate the DEF filler. I was hoping to do something better than leave it on the stock bracket, although it's yet another thing that's probably over complicated and not worth the expense.. So let's get to it!
Here's the stock filler disassembled, and I've already cut the tubing off the quick connects that attach to the tank.
The stock tubing is some kind of heat shrink tubing, it's just shrunk over barb fittings. Ram actually has a document on extending the DEF filler if you look hard enough on the bodybuilder site, it's one of the pages in the box off document.
The trick is finding the right tubing to replace the stock tubing. Apparently the urea in DEF is pretty aggressive to most rubber, so normal fill neck hose that's resistant to gas/diesel won't do. It is possible to get "DEF transfer hose" but pretty much everywhere I looked was either out of stock or you had to buy at least 100'.
The Ram document mentions to use "commercially available Tygon tubing" so naturally that led me to Tygon MSDS sheets and eventually good old McMaster-Carr. It seems that most all Tygon tubing has excellent resistance to urea. The vent needs 1/2" ID tube, and the fill needs at least 7/8" ID but 1" would be easier to get over the barb.
In the end I bought F-4040-A tube for the vent, and I would have liked to also use F-4040-A for the fill because it is also oil resistant (not that that is needed for this application) but the largest it comes in is 3/4". I ended up buying 7/8" E-3603 for the fill. I would have liked to have gone with 1", however McMaster doesn't sell that in a 5 foot length - have to jump up to 10 feet and at around $10/ft that's money I don't need to spend. Long story short, the 7/8" will fit but it takes a lot of effort.
Alright, enough about expensive hose. How do we mount the fill neck - there's a lot of angles involved here, including that the fill neck has to be at a 30 degree tilt per Ram's specs. Off to Fusion360 to build a sheet metal fill neck surround.
I printed it out at 2/3rds scale so it would fit on the paper and do a sanity check on some of the angles.
Turns out I didn't have it perfect, but it was close enough in the end. Off to the CNC plasma table to cut it out of 16 gauge steel. The table I have access to is in bad need of some adjustment and maintenance (I'm working on that too) so the corners are a little ragged, but it's close enough.
This is a really difficult shape to bend up, at least on the box brake I have. The flanges on the outside ended up being a bad idea, I tried to make them work but in the end I made a frame out of 1" square tube and chopped the flanges off. Many, many hours later here's the first time I am getting it to fit half decent.
Tacked in place and test fitting the fill neck.
Much welding and grinding later and I am pretty happy with the result.
The hose will be routed through the skin and over to the tank. The fill neck is in basically the same height as before, just moved rearward a bit.
Seriously though, it’s looking awesome, I’m so jealous.
