Truck tire wheel-off events can cause catastrophic failure so it is important that you remind technicians and customers to follow a proper tire inspection routine to ensure greater tire and wheel-end safety.

“When wheel-off events occur, they result in damage to property or people, and the main culprit of these events is a lack of basic, routine maintenance,” says Doug Jones, customer engineering support manager, Michelin Americas Truck Tires.

The most critical element of any tire maintenance program is maintaining correct tire pressure. Remind customers to have an accurate tire pressure gauge and show them how to check the pressure in the truck’s tires everyday on all tires, including inner duals.

During pre- or post-trip inspections, advise customers they should look at the entire wheel end, including the tire, wheel, studs and fasteners, the hub area and the brakes. While there are many different methods for tightening wheel fasteners, the most accurate approach has been the manual torque method. It is important that on disc wheels each fastener is torqued to 400 to 500 ft.-lbs.

In a combined effort with the Tire Industry Association, Michelin has produced a video outlining steps to help ensure wheel-end safety and help avoid wheel-offs or wheel-end fires. It is available on the Michelin Truck Tires YouTube channel (www.youtube.com/watch?v=wrsj2UoMeys) as well as the Michelin Web site, www.michelintrucls.com and TIA Web site, www.tireiindustry.org. n

Slack Adjuster Maintenance

Mack offers the following maintenance and lubrication recommendations for Gunite automatic slack adjusters on LEU, MRU, GU, CHU and CXU vehicles.

Every three months or 25,000 miles:

Check the condition of the foundation brakes, including drums, shoes, linings, cams, rollers, bushing, etc.

Check for structural damage to the housing, worn clevis, worn clevis bushings and the boot for cuts or tears. Replace if necessary.

After allowing the brake drum to cool to room temperature, check for correct chamber stroke. Because of the variety of vehicle operating conditions, you may need to perform chamber stroke tests at earlier intervals.

Gunite automatic slack adjusters are factory lubricated and sealed to protect against dirt, water, salt and other corrosive elements. Nevertheless, periodic lubrication is recommended. Every six months or 50,000 miles, grease the slack adjuster using an approved grease.

The adjusters have a grease fitting to allow lubrication during normal chassis servicing. With a conventional grease gun, apply lubricant until grease appears on the camshaft or grease flows from the grease relief.

The current Gunite automatic slack adjusters are produced without a grease relief, forcing lubricant through the drilled worm wheel onto the camshaft. Previous designs incorporate a grease relief.

National Lubricating Grease Institute (NLGI) grade 1 and 2 greases without moly sulfides or EP additives having a working range of -40ºF to +120ºF are the recommended greases. Thick greases should be avoided. n

Recommended Brake Drum Applications

Webb Wheel says its 76864 brake drum should only be used for standard duty, van, tractor-trailer or flatbed combinations. Standard duty cycle is considered typical line haul, over-the-road applications. Webb says that duty cycle is independent of gross axle weight ratings.

The 76864 drum is not recommended for liquid and dry-bulk tankers, dump trucks, dump trailers, refuse applications or other similar applications.

For heavy-duty cycle applications (applications that are subjected to a higher frequency of mechanical and/or thermal cycling compared to standard duty), customers should use Webb Part No. 66884 for 16.5 x 7 brake size.

The National Highway Traffic Safety Administration (NHTSA) has issued the following recalls:

Volvo Trucks North America is recalling more than 60,000 tractor-trailer trucks to address potential steering problems. The recall affects certain VNL and VNM trucks from the 2001 to 2006 model years. A ball socket could separate in the steering system, causing the truck to completely lose steering control. The steering loss could result in a crash.

Daimler Trucks North America is recalling certain Detroit Diesel engines, models DD13, DD15 and DD16, manufactured between January 1, 2007, and April 5, 2010. Should the fuel filter become restricted, the low-pressure fuel flange may develop a crack resulting in diesel fuel leaking.

As a result of an error in the installation process, the park feature (Part Nos. FO-5506B-DMS, F0-6506B-DM3, F-5505-DM3 and F-6505B-DM3, and EH-6E606B-CD, EH-6E606B-P, EH-6E706B-CD, EH-6E706B-P and EH-6E706B-UPG) may not engage on certain Eaton and Fuller branded medium-duty, automated mechanical transmissions. If the park feature does not engage, the vehicle can move without warning, possibly resulting in personal injury or death.

The rear axle outer end hub on certain Kenworth model year 2010 T2000, T660, T800 and W900 vehicles manufactured between July 30, 2009, and September 8, 2009, may not have been primed with oil properly during the rear axle installation process. Lack of oil may cause the outer end bearing to heat up and/or seize, possibly resulting in the overheating of the wheel end. A wheel-end fire could occur.

Certain Volvo model year 2010 XC70 vehicles manufactured from December 5, 2006, through October 1, 2009, fail to comply with the requirements of Federal Motor Vehicle Safety Standard No 110, “Tire Selection and Rims.” The FMVSS label, tire and loading information label and a page in the owner’s manual contain incorrect maximum permissible inflation pressures according to FMVSS 110. n

Denso suggests that when a vehicle is brought in with a charging system complaint to first check alternator performance.

If an alternator test bench is available, follow the procedures found on the bench tester’s instruction manual to conduct an alternator performance test. This test will determine if the alternator’s output is within performance specifications.

If the output is within specifications during the bench test, resolve problems in the remainder of the vehicle’s charging circuit and other electrical circuit that may affect charging circuit performance. Refer to the vehicle manufacturer’s service manual for the proper procedures to follow to identify and correct charging circuit problems.

If the bench test results show the alternator output is out of specification, replace it. Follow the vehicle manufacturer’s recommended procedure for inspecting the remainder of the charging circuit and other electrical circuits that may affect charging circuit performance.

If the alternator you are testing has an internal regulator, and the bench test identified the regulator as defective, it may be possible to replace the internal regulator and return the alternator to service. If the regulator is replaced and the alternator returned to service, follow the vehicle manufacturer’s recommended procedure to inspect the remainder of the charging system and other electrical circuits that may affect charging circuit performance.

Fifth Wheel Cylinder Kit Installation

Use the following procedure when installing an air actuated fifth wheel cylinder kit on Fontaine Ultra LT series fifth wheels.

• Remove the fifth wheel from the mounting bracket. Fontaine advises cleaning the fifth wheel prior to installing the kit.
• Place the fifth wheel in the upside down position making sure the wheel is placed on a suitable work surface.
• Remove the pull handle spring from the fifth wheel. (See Figure 1.)
• Install the exhaust valve into the air cylinder. (See Figure 2.) Make sure the exhaust valve is oriented properly.
• Install the new air cylinder making sure it is oriented properly. (See Figure 3.)
• Reinstall the fifth wheel back on the mounting brackets..
• Insert the air supply line into the quick disconnect on the exhaust valve.
• Open and close the fifth wheel using the air cylinder to ensure proper function.
• Tilt the fifth wheel forward to ensure that the cylinder and air supply lien does not interfere with another component.

Impact vs. Chrome Sockets

Chrome hand sockets and impact sockets have many differences that go beyond just appearance, according to Snap-on Tools, and each is designed and manufactured for specific applications.

For instance, a technician should never use a chrome hand socket on an impact gun – only use impact sockets. The impact socket has thick walls and is finished in a black phosphate or black oxide finish. Impact sockets also have a cross hole in the handle end for use with a retaining pin and ring or locking pin anvil to allow the socket to be securely attached to the square drive of an impact gun.

Power sockets, designed for use with power nut runners, multi-spindle machines and angle head nut drivers, may cause some confusion since they are offered in a black finish. But, Snap-on notes, they are stamped “WARNING: NON-IMPACT.”  Power sockets are heat treated to a higher hardness than either impact or hand sockets. According to Snap-on, this high hardness, combined with thick socket walls, produces a strong, wear resistant socket. This socket is suited for assembly-line work where it is not subjected to high-impact loads.

Hand sockets have a thin wall which allows for clearance in general applications where hand torquing is used. Hand sockets, except for those intended for industrial use, are chrome plated. Although hand sockets and power sockets can fit the impact wrench, they are not the same and must not be used on impact tools, Snap-on warns.

One difference you can’t see between these two types of sockets has to do with the way each has been heat treated and/or the composition of the metal used. The impact socket made out of medium carbon alloy steel is heat treated to a low hardness range which has been optimized for impact use. This means that under heavy, continuous use, an impact socket will withstand the impact blows and will wear rather than break.

Hand sockets are made of medium carbon alloy steel that is heat treated to a hardness range commensurate with their size and configuration. Hand sockets are heat treated to a comparatively higher hardness for high strength and more wear resistance than impact sockets. But, they are made to sustain hand applied torque applications only.

Using only impact sockets on impact wrenches reduces the risk of injury, delays and damaged work. It’s relatively easy to spot a hand socket that’s been misused on an impact wrench, Snap-on says. Check the square drive end for signs of damage and distortion. Cracks and other damage often will appear around the wrench end as well.

Improperly using hand sockets on impact tools may be hazardous as they may crack. By knowing the difference between the various types of sockets and using them appropriately, you will be able to ensure a safer and more efficient work environment.

Sliding Pins and Bolts for Disc Brakes

For standardization reasons, reducing the number of spare parts and simplifying the handling of spare parts, Haldex changed the sliding pin and bolt design on is ModulX disc brake.

The modification to the sliding pin is internal and is basically a change in machining concentration to where the bolt head flange meets the sliding pin edge (as shown in Figures 1 and 2). There is no effect on other components. The modified sliding pin is asymmetric, but it is not possible to fit the pin and bolt incorrectly since the bolt can only be entered into the pin from one direction.

To meet the changed sliding pin mechanism, the attachment bolt is modified in design. The most noticeable change is a greater flange on the new bolt head.

The old bolt head (Figure 1) is tightened to 162 ft.-lbs. and the new bolt (Figure 2) is tightened to 206 ft.-lbs.

The new sliding pin cannot be used with the old bolt and vice versa.

Replace Damaged VacValves

According to Donaldson, the Vacuator Valve, standard on the majority of its air cleaners, is an important part of the functionality of the air cleaner during the pre-cleaning stage.

If the VacValve is cracked, torn, remains open or is missing, dust particles that normally are expelled can deposit themselves onto the filter and will shorten air filter service life. If the valve is cracked, torn, remains open or is missing, replace it.

For proper operation, the VavValve should be located at the lowest point on the air cleaner or with the dust cup pointing down.