Story at a Glance
- A cab-to-box pass-through improves livability, comfort, and stealth access
- An accordion boot provides a flexible, weather-sealed connection
- You’ll need to cut matching openings and fabricate a flange on the box side
- Ideal for DIY box truck campers, mobile workspaces, and vanlife-style builds
- The boot is made of EPDM rubber with a spring steel clip
- Accordion boot box truck conversion
If you’re converting a box truck into a camper, mobile office, or adventure rig, you’ve probably focused on layout, insulation, and storage — but what about access between the cab and the box?
Adding a pass-through is one of the most functional upgrades you can make to your box truck project. It improves comfort, mobility, and makes your vehicle feel more like a cohesive living or working space — not just a cab and a box stuck together.
In this article, we’ll walk you through the smartest and most efficient way to create a cab-to-box connection using an accordion boot — the flexible, weatherproof solution that’s ideal for DIY conversions.
Why Cab Access Matters
When you’re living, camping, or working out of a box truck, being able to move freely between the driver’s cab and the rear box is a big deal. Without access, you’re forced to exit the vehicle to reach your living space — inconvenient at best, and risky in bad weather or unfamiliar areas.
With cab access, you gain:
- Safe and stealthy entry/exit
- Better insulation and airflow control
- Easier communication and gear access
- A more connected, RV-like experience
How to Add Cab Access the Smart Way
The best way to fill the gap between your cab and box is with a flexible accordion boot. Originally designed for truck campers and semi-sleepers, it’s become a viable solution for DIY box truck converters.
What is an accordion boot?
It’s a rubber bellow-style gasket made from black EPDM rubber with an embedded spring steel clip that run the length of the boot. The accordion ribs allows flexing movement between the cab and box and creates a sealed, weatherproof connection.
Step-by-Step Installation Overview
Here is an outline for creating a pass through for your box truck project to facilitate the installation of the rubber accordion boot.
Cut Matching Openings
Cut through the rear cab wall and front box wall
Ensure the opening is centered and structurally supported
Make sure both cutouts are the exact same size.
Rubber require a minimum of 1″ radius in the corners
Clean the edges thoroughlyFabricate a Flange on the Box
Use 1/8″ aluminum or steel strips to create a rigid flange around the cutout
The spring steel clip in the boot needs something to grab
Rivet or screw the flange in place and seal with polyurethane sealantInstall the Accordion Boot
Slide the boot edge over the cab flange
Repeat on the box side
Compress slightly for a snug fit
Tools
- Measuring tape
- Jigsaw or reciprocating saw
- Marker
- Soft Mallet
- Screw Driver
- Drill
Materials
- Accordion boot
- Aluminum or steel flat bar (for flange)
- Rivets or self-tapping screws
- Polyurethane sealant (optional but recommended)
Don’t skip the flange — most box trucks don’t have a lip for the boot to grip.
Pro Tips for Better Results
- Add a blackout curtain or sliding panel inside the cab
- Test your seal with a hose or flashlight at night
Where to Get the Right Accordion Boot
Not all boots are created equal. Our accordion boots are made from heavy-duty EPDM rubber with embedded spring steel clips — flexible, secure, and easy to install.
Rubber Boot Seal
You can order rubber boot material for your special project requiring pass through access. These seals are extruded from a durable EPDM synthetic rubber compound and incorporate a flexible spring steel clip for attachment to any flange. This material is sold by the foot.
Frequently Asked Questions (FAQ)
Can I use an accordion boot without cutting the cab?
No. The accordion boot requires a matching pass-through opening in both the cab and the box to function properly.
What if my box doesn’t have a flange?
You’ll need to fabricate one using 1/8″ flat bar stock (aluminum or steel) so the boot’s spring clip can attach securely.
Is the accordion boot waterproof?
Yes, when installed correctly and optionally sealed with silicone, it forms a weatherproof barrier against rain, dust, and wind.
Can I remove the boot later?
Yes. but with some caution. The spring steel clip allows for semi-permanent installation, allowing for removal or replace if needed.
Accordion Boot Box Truck Conversion References
EPDM Roofing Association. Properties of EPDM rubber. https://epdmroofs.org/epdm/technical-information/
Expedition Portal Forum. DIY truck camper projects and fabrication tips. https://www.expeditionportal.com/forum/
National Highway Traffic Safety Administration. (2021). Vehicle modification safety guidelines. https://www.nhtsa.gov
Truck Camper HQ Blog dedicated to the Truck Camper World https://truckcamperhq.com
DIY Truck Camper Builds. How to build a pass-through between truck cab and camper. Retrieved from https://www.truckcamperadventure.com