wheel or rim. If two different size tire assemblies are furnished on the truck tractor, one tire
assembly of each size, tread design and load range (ply rating) shall be furnished.
3.4.11 Brakes. Brakes shall conform to Federal Motor Carrier Safety Regulations 393.40
through 393.42(b), 393.43, and 393.45 through 393.52.
184.108.40.206. Service brakes. The vehicle shall be equipped with full-air brakes on all wheels.
The braking system, complete with all necessary components, shall include:
(a) Air compressor, unloader-head type, engine driven and engine lubricated, air- or
water-cooled, and having a capacity of not less than 14-1/2 cubic feet per minute (cfm)
(b) Air storage reservoir(s) with not less than 6,000 cubic inches total capacity, each tank
equipped with a drain, and with safety and check valves between the compressor and
the last reservoir tank
(c) Foot control, suspended or treadle type
(d) Air control valves
(e) Air pressure gage, visible to the driver
(f) Low air pressure warning, visible and audible
(g) Service brake stop lamp twitch
(h) Automatic moisture ejector
(i) Parking (emergency) brakes on both axles of the rear bogie
(j) Automatic slack adjusters.
220.127.116.11.1 Air dryer. A replaceable cartridge desiccant type air dryer shall be installed in the
air brake system. The dryer shall have the capability of removing not less than 95 percent of the
moisture in the air being dried. The dryer shall have a pre-cooler and a filter to screen out oil and
solid contaminants. The dryer shall have an automatic self-cleaning cycle and a thermostatically
controlled heater to prevent icing of the purge valve.
18.104.22.168 Brake controls for use from a towing vehicle. When specified (see 6.2), the vehicle
shall be furnished with a system for controlling the brakes from a towing vehicle (wrecker). The
installation shall be complete with air brake couplers, relay emergency valve with no-bleed-back
feature (except when spring applied emergency brakes are furnished), additional air lines and
fittings. The service and emergency couplers shall be mounted on the front in a protected position
providing for ready attachment of air hoses from a towing vehicle. The service and emergency
couplers shall be identified and provided with dummy gladhand couplers with chains. The system
shall not compromise conformance to any Federal Motor Carrier Safety Regulation referenced
herein or to any Federal Motor Vehicle Safety Standard.
Trailer brake control system. In addition to the components specified in 22.214.171.124 and 126.96.36.199.1,
a trailer brake control system shall be furnished. The trailer brake control system shall include: