CTIS Wheel-End Valve Service: What It Really Takes
When a wheel-end valve goes down, one question decides your day: can your mechanic fix it where the truck is sitting, or does the truck wait?
Everything else — pressure ratings, flow capacity, patents — matters less than that. Here is how the AirDown wheel-end valve is serviced, what it costs, and how that compares to what TIREBOSS publishes.
The AirDown wheel-end valve
The AirDown valve is covered by US Patent 10,493,808 B1, “Central tire inflation system,” granted December 3, 2019 to Airdown Inc — inventors Scott McCauley and Alfred Robert Tomlinson. It remains active to 2038. A second patent in the same family, US 11,529,831 B2, granted December 20, 2022, covers the control system. Both are verifiable at the USPTO.
The design point that matters day to day: it is fully rebuildable in the field.
A mechanic can completely rebuild an AirDown wheel-end valve in about 20 minutes, on the truck, using our Minor Rebuild Kit — $65.85. No return authorization, no shipping the assembly out, no waiting on a dealer.
That price is published on our site. So is every other part we sell:
| AirDown part | Price |
|---|---|
| Minor Rebuild Kit | $65.85 |
| Double Piston Wheel End Major Seal Replacement Kit | $137.55 |
| KAM Rotary Union | $237.20 |
| AirDown Wheel End Valve (complete) | $480.05 |
| AirDown Low Pressure Switch | $102.72 |
What TIREBOSS publishes
To their credit, TIREBOSS publishes their service manual openly. The TB2 Service Manual v2.4 (January 2025 update) includes a section titled “Wheel End Valve [WEV] Service Procedure.”
That procedure covers replacing the diaphragm — TPC Part# WEV-1000-02. The published steps: remove the valve caps in a cross pattern with a 5/32″ allen key, inspect the diaphragm for “cracks, rips, or tears,” replace if found, clean the passages with brake cleaner and compressed air, reinstall, and “Torque bolts to 50 in.oz.” The manual states that “Work should only be carried out by trained personnel.”
Source: TB2 Service Manual v2.4, tireboss.com, accessed July 21, 2026.
What is not published anywhere on tireboss.com, as of that date: part prices, warranty terms, support hours, or a service response commitment.
Support: what happens when the truck is down
We run two service trucks with two technicians on the road every day. When a customer has a system down, we are typically on site within 12 hours.
We also stock replacement parts that fit TIREBOSS systems, at published prices, because their owners kept asking:
| TIREBOSS-compatible part | Price |
|---|---|
| TB Airline Hanger | $475.36 |
| TB Inflate/Deflate Solenoid | $89.32 |
| Tireboss Rockwell Drive Axle Manifold | $75.00 |
| TB 225-2103 | $13.00 |
The comparison, plainly
| AirDown | TIREBOSS (per published docs) | |
|---|---|---|
| Wheel-end valve service | Full rebuild, in the field | Diaphragm replacement (WEV-1000-02) |
| Time | ~20 minutes | Not published |
| Kit price | $65.85, published | Not published |
| Parts prices | All published online | Not published |
| Response commitment | Typically within 12 hours | Not published |
| Field technicians | 2 trucks, 2 techs, daily | Not published |
Publishing our prices
We publish our prices because you should not have to call to find out what a part costs while a truck sits.
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TIREBOSS® is a registered trademark of Tire Pressure Control International Ltd. AirDown Inc is not affiliated with, authorized by, or endorsed by Tire Pressure Control International Ltd. Comparisons reference publicly published TIREBOSS documentation as of July 21, 2026. Trademark references are for compatibility identification only.