Under the Hood – August 20071

Tie Rod Arm Removal & Installation
ArvinMeritor recommended the following procedure for first removing and then installing the tie rod arm for MFS-14-143ANN-58 and -60 axles on International trucks.

Use a brass or synthetic mallet for assembly and disassembly procedures in order to prevent pieces of parts from falling off.

To begin the removal process, remove the cotter pins and nuts that fasten each tie rod end to the tie rod arms.

If the cross tube clamps are track-welded, do not remove the track weld during tie rod assembly removal or the clamp force will be reduced. Replace the cross tube if the weld is broken. Also, do not heat the tie rod arm to remove the cross tube assembly because heating will soften and damage parts.

After you have removed the cotter pins, disconnect the cross tube assembly from the tie rod arms.

Remove the cotter pin and nut that fastens the tie rod arms in the knuckle.

Finally, remove the tie rod arms from the knuckle and remove the key.

To begin installation, press the key into the slot in the new arm, (Part Nos. 3133R7350 and 3133S7351).

Install the tie rod arm into the knuckle.

Install the nut onto the tie rod arm and tighten the nut to 550 to 1025 lb.-ft.

Install the cotter pins and, if necessary, tighten the nut to increase the final torque value until the holes are aligned. Do not loosen the nut to install the cotter pin.

Check the tie rod boot and boot seals for damage. If there is damage, replace the entire tie rod end.

Clean and dry the tie rod end taper and the tie rod taper hole.

Install the tie rod ends into the tie rod arms so that the threaded portion of the tie rod is installed into the cross tube beyond the end of the slot. Ensure that the clamp tab is seated firmly against the cross tube.

Install the nuts into the tie rod ends and tighten the nuts to 160 to 320 lb.-ft.

Install the cotter pins and tighten the nut until the holes are aligned.

If necessary, adjust the toe. Refer to the procedures for measuring and adjusting the toe in Maintenance Manual 2, Front Non-Drive Steer Axles. Tighten the cross tube clamp bolt and nut to 60 to 80 lb.-ft. if the toe is readjusted.

False Reporting Of High Temperature
On certain Mack CV model chassis equipped with an Allison automatic transmission, the vehicle electronic control unit (VECU) might incorrectly identify a transmission oil temperature that is above normal.

Should this condition occur, proceed as follows. Using V-MAC Online, upgrade the VECU software to step 12A. Download the software and the OEM datafile.

Using V-MAC Dealer Programming software, read and save customer data. Using V-MAC Dealer Programming software, reflash the VECU per the instructions outlined in the V-MAC Support Software User’s Guide, 8-353.

Reprogram the VECU and restore customer data using the V-MAC Dealer Programming software per the instructions outlined in the same user’s guide.

Calibrate the throttle pedal. The throttle pedal can be recalled manually by slowly depressing, and then releasing the pedal three times. The throttle pedal also can be recalibrated by using VCADS Software. Clear any fault code and then perform a short road test.

Brake Drum Change
As of March 2006, Webb Wheel’s 66864 rear 161/2 x 7 brake drum will have a different look. The company has added external rest pads and removed valve stem slots.

Customers are advised that all application specifications remain identical between the 66864 drums shipped prior to March and those shipped after March, despite the product’s new appearance.

Charge Air Cooler Hose Clamp Breakage
If you find instances of a broken hose clamp at the connection between the turbocharger compressor and the charge air cooler hose on Mack CX model chassis, a revised clamp (Part No. 83AX1055) is available. This clamp is less prone to breakage, and should be used for any replacement needs. Torque specification for this clamp is 77 lb.-in.

New Valve Bridge Needed
Caterpillar has announced that a new valve bridge may need to be installed on the following truck engines: 3054, 3406E, C-10, C-12, C-15, C-16, C15 and C7.

According to the company, there have been instances of the valve bridge contacting the rotocoil when it should rest on the valve system. Before attaching the rocker arm assembly to the head, check the gap between the valve bridge and the rotocoil and make sure that you seat the valve bridge by applying pressure with your finger on the valve bridge. The minimum gap between the rotocoil and the valve bridge should be .020″.

When the valve bridges are installed on the heads, measure the gap between the rotocoils and the valve bridges. If the minimum gap is not met, a new valve bridge needs to be installed.

Revised Engine Brake Solenoid
On Mack E-Tech and ASET engines equipped with a Mack PowerLeash engine brake the solenoid wires may rub against adjacent valve train components, resulting in damage to the wire insulation and allowing the solenoid to short to ground.

Should this occur, an inactive engine brake on the affected cylinder head will result and an active fault code (3-5 for the front cylinder head or 3-6 for the rear cylinder head) will be logged. Additionally, damage to the engine electronic control unit (EECU) can result.

If you encounter an engine brake solenoid with damaged wires, there is a revised solenoid (Part No. 805GC54B) available.

This solenoid includes a sleeve approximately 1.25″ in length, which joins the two wires together where the wires exit the body of the solenoid. To provide additional strength, a high-temperature oil resistant tie wrap (Part No. 983472) is used at the end of the sleeve to secure the two wires together. (See Figure 1.)

According to the company, these solenoid revisions, along with properly routing the wires through the solenoid retaining clips will prevent a damaged engine brake solenoid caused by wires rubbing against adjacent valve train components.

The company warns that under no circumstances should a substitute EECU be used when diagnosing engine brake issues.

Tube Replacement
On Caterpillar 3126 engines, use the 164-0201 Tube As to replace the 135-5980 Tube As.

The company warns that in extreme operating conditions, oil pressure pulses may cause the 135-5980 Tube As to crack.

The same pressure pulses also may cause the 167-1709 Pressure Sensor Gp to fail, in which case a 164 diagnostic code will be logged in the engine control module.

A failed sensor may cause an engine shutdown or the engine to run erratically. If the crossover tubes or engine oil pressure sensor needs to be replaced, first remove the six 135-5980 Tube As, the six 113-6135 fittings and the 167-1709 pressure sensor.

Next install six new 16400201 Tube As, six 148-0876 fittings and a new 167-1709 Pressure Sensor Gp.

EGR Cooler Coolant Outlet Hose
Mack announced that exhaust gas recirculation (EGR) cooler internal leakage, where exhaust gases have contaminated the engine coolant, can result in damage to the liner inside the EGR cooler coolant outlet hose in its ASET AC engines.

This is the 90-degree hose located at the front of the cooler that is connected to the coolant return tube at the front right corner of the engine. To avoid subsequent failure of this hose, it must be replaced whenever an EGR cooler is replaced.

Beginning with engine Serial No. 6T1073, a revised EGR cooler coolant outlet hose (Part No. 744GB350A) was implemented into production on all ASET AC engines. This revised hose is a three-ply hose for added durability and is blue in color for positive identification. The previous hose was green.

Safety Recalls
The National Highway Traffic Safety Administration (NHTSA) has issued the following safety-related recall notices.

Electrical System:
Some Blue Bird/Vision (2004 to 2006 models) conventional school buses and non-school buses manufactured from June 2003 through February 2005, have been recalled.

A short can occur in the crossing arm circuit or the 8-way warning light circuit, causing the heavy-duty transistor with built-in circuit protector to trip, resulting in an inadvertent engine shutdown.

A vehicle crash could occur should the engine shut down while the bus is in use, possibly resulting in injury or death.

To repair the problem, relocate the circuits to a separate circuit protected by a circuit breaker.

On certain 2004 model year Kenworth T2000 trucks, the power feed harness P92-1993 terminals were not crimped properly.

This could lead to intermittent power loss affecting the electrical system and possibly result in a fire.

To repair, replace the harness.

Service Brakes:
On some 2004 model year International 9400i trucks, only eight bolts were installed in the brake group connection to the rear axles. The brake group, an assembly that includes the brake shoes, air chambers, slack adjusters and spider, normally is attached to the axle housing with nine bolts.

Without the bolt, the structural integrity of the brake group is questionable. This may result in the loss of braking ability on the rear axles without warning, which may result in a crash.

Inspect the brake group and install the additional bolt if necessary.