Alcohol in the Air Brake System
Bendix Commercial Vehicle Systems discourages the use of alcohol in the air brake system as a means of preventing system freeze-up in cold temperatures. Studies indicate that using alcohol and alcohol-based products removes the lubrication from the components of the air braking system.
In addition, the materials used for the internal seals of the air system components may be adversely impacted by the residue that some anti-freeze additives leave behind. Both are detrimental to air system component life expectancy, causing premature wear. Because of this, Bendix air system components warranty will be void if analysis shows that alcohol was added to the air brake system.
Alcohol is not an acceptable substitute for having adequate air drying capacity. If the air dryer is maintained in accordance with the manufacturer’s recommended practices and you find moisture in the system reservoirs, more drying capacity is required.
Bendix has several options including extended purge air dryers, extended purge tandem dryers in parallel with common control, and air dryers arranged to provide continuous flow as with the Bendix EverFlow continuous flow air dryer module. See Figure 1 for system schematics.
To address concerns with contaminants in trailer air brake systems, the Bendix Cyclone DuraDrain water separator and the Bendix System-Guard trailer air dryer are available.
Bendix also has found some alcohol evaporators, which may be placed in series with a single air dryer, can be restrictive to the output of the compressor. This restriction can cause excessive compressor discharge pressures at the head of the compressor. This is especially true when the air induction to the compressor is pressurized (turbocharged).
High head pressures can shorten the life of the internal components of the compressor discharge and discharge line. Follow all recommended safety procedures when performing any service on a vehicle. Caution: never apply an open flame to frozen air lines and valves; instead move the vehicle to a warm building.
Additionally, before removing contaminants, refer to RP617A procedure for contaminant removal in the Technology & Maintenance Council (TMC) Recommended Maintenance Practices Manual.
PM For Adjustable Bearing Hubs
Volvo says for hubs with adjustable bearing to check the front wheel with a wheel spinner and listen to the bearings during the rotation. If there is any abnormal sound in the bearings, the hub must be removed to inspect the bearings.
If you are not sure of the clearance of the front bearings, measure the bearing with a dial indicator.
- Clean the hub cap.
- Remove the hub cap for grease-lubricated bearings or the plug in the center of the hub cap for oil-lubricated bearings.
- Place the measuring tip on the dial indicator against the spindle bolt when measuring. For oil-lubricated bearings, the axial clearance should be 0.04 mm to 0.12 mm.
- Screw tighten the hub cap and the plug in the hub cap. Torque to 16.26 to 21.69 Nm.
Revised Fan Hub Mounting
CHU and GU model chassis equipped with Mack MP8 engines have a high-mounted fan position. For this application only, the fan hub mounting stud material properties and length have been changed.
The stud material is now grade 10.8 (previously it was grade 8.8), and the stud length has been changed to 45 mm (it was 40 mm) to ensure full nut engagement. Along with the changes to the stud, the nut hex size also has been changed from 15 mm to 16 mm. The torque specification for the 16 mm nut is 70 Nm. This change was implemented into production on March 17, 2008, beginning with engine serial No. 914170.
Safety Recalls/The National Highway Traffic Safety Administration (NHTSA) has issued the following recalls:
- Triangle Suspension Systems aftermarket trunnion suspension components, Part No. EA35-62, sold for use on certain 1970 to 1980 model year Mack trucks with the SS34/SS44 camelback suspension can crack and fail. This can cause the rear suspension to shift. The defective component can be found in trucks repaired between January 3, 2008 and October 7, 2008. The failure can affect vehicle handling and may result in a crash.
- The aftertreatment regeneration device on certain Caterpillar C15 6-cylinder, 151 turbocharged, air-to-air aftercooled diesel engines of 472 to 585 hp, may develop a hole. This hole may allow heat and flame to escape during the regeneration of the diesel particulate filter. This could result in a fire.
- The tire placard on some Daimler Trucks North America Thomas Built Minitour school buses with a GVWR of 10,000 pounds or less, manufactured between September 1, 2004 and November 26, 2008, contain incorrect information, which fails to comply with the requirements of. Incorrect information on the tire placard may lead to tire overloading and possibly cause tire failure. New labels will be sent to owners for installation.
- Twenty-seven 2009 model year Trailmobile trailers equipped with ArvinMeritor axle assemblies have suspect wheel-end studs. The suspect wheel-end studs were improperly tempered, potentially rendering them brittle and susceptible to fracture. If one wheel stud fractures, the remaining wheel studs are required to carry more load. If left in this condition, the remaining wheel studs also may fracture even if they are properly manufactured. Fractured studs could result in a vehicle crash. This also applied to 185 2008 model year LWED, CFB, LWBD, SFB, TSH, TSTD, SBD, SDD, ADD and CDD Manac trailers.
- The rear axle U-bolts on 130 2008 to 2009 model year Hino ND8J, NE8J, NJ8J and NV8J conventional trucks were not tightened properly. The lower spring seat may not contact the axle housing properly, producing a gap on the front or rear side of the axle housing. This gap could allow the U-bolts to loosen or cause the lower spring seat to crack. The axle could become misaligned or separated from the mountings increasing the risk of a crash.
- The high pressure fuel lines and transfer tubes on EPA04 certified MBE900 engines manufactured by Detroit Diesel between March 1, 2004 and July 31, 2006 and found on 26,047 Daimler Trucks school and non-school buses, motor home chassis and trucks, may fatigue and fracture. A fractured fuel line may leak diesel fuel possibly resulting in a fire or fuel may spill on the road causing a slippery surface, possibly resulting in a crash. The vehicles will be repaired with more robust lines and vibration dampers.
- The kingpins on 2,335 2005 model year Great Dane dry freight semi-trailers can break off as the tractors attempt to couple to the trailers. If a kingpin were to break off during over the road operations, it could result in the separation of the trailer from the tractor, which could increase the risk of a crash.
- The headlight switch on 34,269 1999 to 2005 model year Mack CX and 2004 to 2008 model year CXN trucks may fail prematurely resulting in inoperative or intermittent headlights.
