McCONNEL MULTIDRIVEM380‐4&M420‐4
76
Air Brake System for Trailers
The air brakes are a single system. Trailers with single line brakes may be connected at
connection (A) and (B) as illustrated below.
Ensure that the connections on the tractor are clean and dirt free before joining the trailer
air hoses.
Replace any damaged sealing washers.
NOTE
Ensure that the trailer brakes are compatible with the prime mover. The Multidrive has an
option of two fluid reaction valves (FRV) with ratios of 15:1 and 30:1. When coupling the
trailer ensure that the trailer brakes are responding correctly.
Check compatibility between the vehicle and trailer air couplings. The valve in the vehicle's
service coupling is opened by a valve-lifter in the trailer's service coupling, and the
operation of this valve-lifter needs to be checked periodically.
With the trailer connected do not drive away unless the air pressure gauge is indicating
below 5 bar (73 psi).
To prevent undue wear on the tractor brakes please observe the following: -
a) Make sure that the pressure hoses on the trailer are connected.
b) Check the air brakes on the trailer regularly to ensure they are operating correctly.
A B
Emergency Service
Air Brake System
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