This PDF from Stant should tell you which cap works for your model year truck: Stant Catalog. Go to page 98.

 

Disregard...I figured it out. Lots of questions asked so let me give my run-down... Take off both caps. Next, from behind the tank door panel you have to get all 4 of those push tabs loose. Next take off the rubber sheet that surrounds the two filler necks. As you're looking at that sheet from the fuel door side it has two of those crinkle snap tabs on the left and just two spade fingers on the right. Comes off pretty easy. Now that everything is loose/removed carefully remove the entire unit door and all from the vehicle by working it out to the right and kind of toward you.. Once out, the spring on the door hinge came off easily and the pin they speak of comes out from the top down not the bottom up like most would think. Drill the 4 holes like the instructions say, assemble with the provided hardware and then snap it in place with the 4 tabs that we originally took out from behind. (Just line it up and push it pack into place until all 4 snap back in.) Install the rubber sheet back around the filler spouts by inserting the 2 spade fingers then snap in the two catches on the other side. Put the caps back on and done.

 

I chose billet!

 

Where did you get that from?

 

Amazon

 

what about a locking def cap? what's the part number?

 

Bump...

How about securing the caps/doors on a 2019 F350 w/6.7?

 

Edit - post removed

 

Pictures when you’re done please

 

It'll be nice when someone offers a solution for both fuel, and DEF caps.

 

I'm seriously considering this one for my '17 F-250 gasser. A bit pricey though.

 

I just found this. Wasnt even on any Google searches. Found their locking DEF for Dodge Rams and then went to their site. Nothing yet for DEF but this is for the F-250-550

Not cheap but billet- $50

From their site:

This Loc-Sure is a non-vented, screw-in, locking billet cap for the diesel filler neck on the 2008-2017 Ford diesel trucks (F-250, F-350, F-450, F-550).

The Loc-Sure offers protection from fuel thieves and from malicious people who would contaminate your fuel. The Loc-Sure utilizes the parent company's Secure Screw system which has been tested and approved by military and other secure facilities as a low-level human secure system.

The Loc-Sure features a 2.5" diameter top face with scallops and knurling for good gripping. The U-Cup seal contacts both the inside and the outside diameter of the fuel filler rim to ensure a proper seal.

Each Loc-Sure purchase comes with the Loc-Sure cap and a molded Secure Key with complimentary stainless steel key ring. Additional keys can be purchased using the information from our Keys page.

BEM Auto's Loc-Sure body is fully machined from aluminum bars at the BEM Auto factory and is finished in a generic green anodized surface, etched to identify the assembled unit as a diesel only cap. The Secure Screw is manufactured from 18-8 stainless steel to provide good corrosion resistance.

https://www.bem-auto.com/product/loc...iesel-trucks/1

 

That's a nice looking fuel cap. But you can get a locking Stant cap for a lot less.

 

True but it’s plastic and everyone has the same key. This is a lot more secure and designed to Mil-Spec. To each their own. Just another option and still cheaper than the door option.

 

dont waste your money on locking caps.....you can open them by threading a wood screw on a slight angle.

get a locking door instead.