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Owner's manual

T5. How to mount it, feed it air, sound it safely and look after it.

Cover of the T5 owner's manual

UD-T5-OM-01 · Rev C · October 2026 · 25 pages

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Read the safety section of the manual and the Safety notice before you connect air. No pressure rating has been established for the T-Series.

Before you connect air

  1. Hearing. It is extremely loud. Wear hearing protection to test it, and never sound it near people or animals.
  2. Its own air. Never tee into a vehicle's air brakes. Use a pressure switch and a tank with a relief valve.
  3. Bolts. Hand tools only, never a drill or impact gun. Foot: 1/2-13 bolts, SAE flat washers and nylock nuts, never lock washers. Wings, bell pads and foot: finger tight, then a quarter turn more, then stop. Rear caps: black M5 Allen screws on printed washers with nylock nuts, snugged in the star order while you hold the stack centred (on bells 1 and 2 the screw next to the wing goes in from the back). Cracks from over-tightening are not covered by the warranty.
  4. Heat. Keep it 12 in (30 cm) from the exhaust and anything hot. The plastic softens at about 158 °F (70 °C).
  5. First run. Fill the tank to about 50 psi only, then step up while you check for leaks and cracks (manual, page 16).
  6. The law. Check the rules where you install and sound it.

Videos

Rebuilding a rear stack 27 s
Nozzle seal, gasket, diaphragm, gasket, rear cap, then six black M5 Allen screws on printed washers with nylock nuts, snugged in the star order while the stack is held centred.
How the horn goes together 25 s
Manifold, wings, then the bells, each on its own 2 mm mount seal. Finger tight plus a quarter turn, hand tools only.

What is in the manual

Safety3
Know your T55
What's in your horn6
Specifications7
Hardware and tools8
Before you install9
Installation guidelines10
The air system11
Choosing a location12
Mounting the horn13
Air supply14
Valve and wiring15
First run16
Using and caring for the horn17
How the rear stack works18
Servicing a rear stack19
Bells and mount seals21
Troubleshooting22
Parts, warranty and support23
Build and test record24
Drilling template25

More help

The install guide shows where the horn goes on a semi, a flatbed or a pickup, and how the air gets to it. Gaskets, diaphragms, nozzle sleeves and every other part are in the shop. Stuck? Send a message with a short video of the sound.