Mack R Problems by year

The steering arm can develop cracks causing the lever to break without warning.

Fuel injection system reconfiguration to comply with engine emission standards cause higher engine vibration levels which lead to early wear and complete failure of the secondary throttle return mechanism.

Interference between steering gear sector shaft and the frame rail through hole can cause sector shaft wear and can weaken shaft cause it to break.

A tolerance mismatch in the crank assembly of the bosch windshield wiper motor could cause instantaneous separation of the crank from the linkage assembly in the left hand control arm assembly; this would make the system inoperable.

Due to improper and inadequate welding practices, the fifth wheel on the involved vehicles is defective. Frame mounted supports may have incomplete or poor quality welds. The welds could subsequently fail allowing separation of the tractor from the trailer.

The spring seat plate, located between the axle housing and the suspension springs, may deform due to spring bending. As a result, the clamping force in the assembly may be reduced. Loss of clamping force could cause spring failure and the axle will...

The pinch bolt hole center to steering gear input shaft on the lower yoke dimension exceeds specifications. If the pinch bolt becomes loose, it will not engage the steering gear input shaft notch and the shaft could slip off.

In the event of turbocharger compressor wheel failure, one or more of the four capscrews that hold the turbocharger together may be struck by parts of the compressor wheel, resulting in the capscrews being damaged. If these capscrews are damaged to the point...

An improper pinch bolt and nut may have been used in the clamping of the steering shaft to the steering gear input shaft. Due to clamping force loads applied at the bolt, the nut could yield, resulting in looseness of the input shaft yoke. Should this...

The steel brackets on the suspension beam were found to be deficient due to excessive shrinkage and low mechanical properties. Failure of one or both of these brackets could cause a separation of the axle housing from the suspension.

A casting deficiency exists in the lower section of the caps resulting in a reduction in the thickness of the material. Failure of a cap can allow the end of the rear spring to detach from the axle housing.

Delays of up to about 2 seconds may exist in the brake application times to the brakes on the bogie axles in the presence of certain types of wheel speed sensor signal discontinuities or distortions that may occur as a result of sensor wire failure. This...