Interference Between Hood Assist Spring And Charge Air Cooler Coupling Hose
On Mack CTP, CHN and CT models manufactured before April 16, 2007, there may be an interference condition between the hood assist spring and the coupling hose on the charge air cooler inlet. When the hood is closed and the vehicle is in operation, spring oscillations result in a wear mark and an eventual hole being worn into the coupling hose, allowing unfiltered air to enter the air intake system.
To correct this condition, a replacement hood spring (Part No. 57QL262BM) is available. If you see a wear mark in the charge air cooler inlet side coupling hose, replace the existing hood assist springs on both sides of the chassis with the new springs. The hood assist springs must be replaced in pairs.
Replacement Axle Housings
Cracks might develop in the rear axle housings on certain Mack model chassis equipped with AL rear air suspensions and Mack rear axles.
These cracks appear on the top or bottom corners of the housings in the area behind the axle seats. (See Figure 1.)
Affected chassis were manufactured May 2004 or later and are equipped with housing Part No. 19QF5318P7 or 19QF318P8. If you notice axle housing cracks, replace them with the appropriate parts.
Cylinder Head Replacement Kit
Meritor WABCO now authorizes replacement of the cylinder head as a warrantable repair on the WABCO Model 318 air compressor. When diagnosing an air compressor that leads to a problem with the cylinder head, the cylinder head should be replaced rather than replacing the compressor.
Before you disassemble the air compression, you must contact the ArvinMeritor OnTrac Customer Service Center at 800-535-5560.
