When The Cold Weather Hits,There’s Help

As the cold weather approaches,fleets and owner operators will begin to winterize their vehicles, especially against air system freeze-ups. Here are some basic tips for optimum cold weather operation from the brake system experts at Bendix Commercial Vehicle Systems LLC.

GEngine Idle

Avoid idling the engine for extended periods of time. Winter idling is a major factor in compressor discharge line freeze-ups, which account for a significant number of compressor failures annually.

The discharge line recommendations – listed in the section below – are important for all vehicles, especially when extended engine idling cannot be avoided.

GDischarge Lines

The discharge line should slope downward from the compressor discharge port without forming water traps, kinks, or restrictions. If it crosses over from one side of the frame rail to the other, it should occur as close to the compressor as possible. Fitting extensions must be avoided. Recommended discharge line lengths and inside diameters are application dependent as follows:

Typical P&D, School Bus & Line Haul –

The maximum discharge line length is 16 feet+.

Length

I.D. Minimum

Other Requirements

 

 

 

6.0 – 9.5 ft

½ inch

None

9.5 - 12 ft

½ inch

The last three (3) feet,

including the fitting at the end

 

 

of the discharge line, must be

 

 

insulated with ½ inch thick

12 – 16 ft

5/8 inch

closed cell polyethylene pipe

 

 

insulation

 

 

 

Severe Service / High Duty CycleVehicles (CityTransit Coaches, Refuse Haulers, etc…) –

The maximum discharge line length is also 16 feet+.

Length

I.D. Minimum

Other Requirements

 

 

 

10 – 16 ft

½ inch

None

 

 

 

+If the discharge line length must be less than six (6) feet or greater than 16 feet in these applications, contact your local Bendix Account Manager, or the Bendix Tech Team at 1-800-AIR-BRAKE for additional information and assistance.

GSystem Leakage

Check the air brake system for excessive leakage using the Bendix Dual Circuit Brake System Troubleshooting guide (BW1396). Excessive system leakage causes the compressor to pump more air and moisture into the brake system.

GReservoir Draining

(System without an air dryer)

Routine reservoir draining is the most basic step (although not completely effective) in reducing the possibility of freeze-up. All reservoirs in a brake system can accumulate water and other contaminants, which must be drained. The best practice is to drain all reservoirs daily.

After turning off the engine, drain all of the air from each reservoir (Alternate Method - Open the drain cocks on all reservoirs and leave them open over night to assure all contamination is drained. See Bendix SD-04-400).If Bendix® DV-2automatic drain valves are installed, check their operation before the weather turns cold (see our SD-03-2501). While the need for daily reservoir draining is eliminated through the use of an automatic drain valve, periodic manual draining is still required.

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BENDIX BW2657 manual Engine Idle, Discharge Lines, System Leakage, Reservoir Draining