Lock the Fuel Cap on Your Knapheide Truck
Every Knapheide Compartment Locks. Now the Fuel Cap Does Too.
Your Knapheide service body has a lock on every compartment, every drawer, every door. But the fuel cap on the Ford or Ram chassis? Wide open. The Work Truck Fuel Vault adds the fuel cap lock your Knapheide truck needs.
Founders Edition pricing — starting at $99.95 (Save up to $50)
Locked Body. Unlocked Fuel.
Knapheide builds the best locked service bodies in the industry. But the fuel cap isn\'t on the body — it\'s on the chassis. And the chassis has no lock.
- Every Knapheide compartment locks — the fuel cap doesn't
- The fuel cap is on the Ford/Ram chassis, not the Knapheide body
- Ford and Ram provide zero fuel cap security on chassis cabs
- An unlocked fuel cap is the biggest security gap on your Knapheide truck
- Fuel theft, siphoning, and contamination are constant risks
- Locking gas caps don't match Knapheide's security standard
Now the Fuel Cap Locks Too
The Fuel Vault adds a real lock to the fuel cap area on your Knapheide truck. Armored door, tumbler lock, security torx — it finally matches the security of your Knapheide body.
- Armored locking door over the fuel cap and filler area
- Tumbler lock + security torx — matches Knapheide body lock quality
- Full coverage — cap, filler neck, and access area all locked
- Zero interference with Knapheide compartments or doors
- Bolt-on in 8–15 minutes — no drilling or cutting
- Made in the USA with Limited Lifetime Warranty
The Part The Factory Forgot
The Work Truck Fuel Vault is an armored, locking fuel door that covers the entire fuel access area on your work truck. No more exposed caps. No more easy targets.
Why Didn't This Exist Before?
Despite billions lost to fuel theft every year, nobody built a real solution for commercial work trucks. Here's why.
"Good Enough" Thinking
The industry defaulted to cheap aftermarket locking gas caps. A $15 key-locked cap was considered good enough — until thieves proved otherwise with a pair of pliers.
Upfitters Focus on the Body, Not the Cap
Manufacturers like Knapheide and Reading engineer every compartment lock on the service body — but the chassis fuel pocket belongs to Ford or Ram. Nobody owned the gap.
The Zero-Drill Engineering Problem
Consumer billet doors are made for flat pickup beds. The recessed fuel pocket on a commercial chassis is a completely different geometry — and drilling risks voiding the chassis warranty.
The Cost Was Just "Absorbed"
Fleets treated fuel theft like weather damage. A $500 siphoning hit got buried in operating expenses. Without a purpose-built product available, the problem was simply accepted.
The Work Truck Fuel Vault is the industry's first drop-in armored fuel door that uses existing factory mounting points. No drilling. No cutting. No warranty risk.
Lock Every Knapheide Fuel Cap
Contractors
Lock the fuel cap like you lock the tools. Complete the security.
Fleet Managers
Lock every fuel cap across your Knapheide fleet.
Government
Municipal Knapheide trucks need locked fuel caps.
Utility
Lock the fuel on every Knapheide utility truck.
Knapheide Dealers
Add a fuel cap lock to every Knapheide delivery.
Owner-Operators
One lock, done. Your Knapheide is now fully secured.
Chassis Compatibility
Purpose-built for the most popular commercial chassis platforms in the industry.
Ford
Super Duty & Commercial Chassis
- F-350 Chassis Cab
- F-450 Chassis Cab
- F-550 Chassis Cab
- F-600 Chassis Cab
- E-350 / E-450
- F53 Workhorse
Ram
Chassis Cab Heavy Duty
- Ram 3500 Chassis Cab
- Ram 4500 Chassis Cab
- Ram 5500 Chassis Cab
Our Guarantee
Limited Lifetime Warranty
Built to last. Warranted against defects in material and workmanship for the life of the vehicle on which it was originally installed.
30-Day Money Back
Not satisfied? Return within 30 days of receipt for a full refund. No questions asked.
Free Replacements
If your Fuel Vault is defective under normal use within the warranty period, we replace it at no charge.
Frequently Asked Questions
How do I lock the fuel cap on my Knapheide truck?
The Work Truck Fuel Vault is the armored locking fuel door that covers and locks the entire fuel filler area on the Ford or Ram chassis under your Knapheide body. Bolt-on install in 8–15 minutes.
Why doesn't my Knapheide truck have a fuel cap lock?
The fuel cap is on the Ford or Ram chassis — not the Knapheide body. Ford and Ram don't include any fuel cap lock or fuel door on chassis cab trucks.
Is a locking cap enough?
For a premium Knapheide truck, no. Locking caps are defeated in seconds and only cover the cap. The Fuel Vault covers the entire filler area with armored protection.
Does it work with all Knapheide body types?
Yes — KnapService, KUVcc, Utility, Forestry, Crane, Mechanics, Platform, and Stake bodies. The Fuel Vault mounts to the chassis, not the body.
How does it install?
Bolt-on in 8–15 minutes. No drilling, cutting, or body modifications.
How much?
From $99.95 with free shipping.
Warranty?
Limited Lifetime Warranty and 30-day money-back guarantee.
Lock Your Knapheide Fuel Cap — Starting at $99.95
Fuel cap lock for Knapheide trucks. Armored door, tumbler lock, bolt-on. Lifetime warranty.
Secure checkout • Free US shipping • No charge until your order ships