This is the PayStar air compressor manual, publication S04055, covering the MCAC 476 unit on International PayStar, ProStar, TranStar and WorkStar vehicles. It describes the compressor, maintenance, full disassembly and assembly, and troubleshooting tests.
Official document details
| Brand | International Trucks (Navistar) |
| Model coverage | PayStar, ProStar, TranStar and WorkStar (MCAC 476) |
| System / Group | 5000 Series (PayStar) / Air Compressor |
| Publication no. | S04055 |
| Year / Revision | December 2010 |
| Pages | 39 |
| File size | 0.7 MB |
| Format | |
| Language | English |
Inside the PayStar air compressor manual
- Description, components and name plate
- MCAC 476 air compressor removal and installation
- Cylinder head and crankcase disassembly
- Clutch housing and piston service
- Air compressor assembly and cylinder head assembly
- Troubleshooting table, tests and torque chart
Copyrighted by Navistar in December 2010, the manual describes how the unit maintains air pressure for the brake and auxiliary systems, engaging and disengaging its mechanical clutch as reservoir pressure crosses the regulated limits while the crankshaft turns continuously. Remove-and-install steps cover draining the cooling system, disconnecting air and coolant lines, and handling a component that weighs about 74 lbs. A full disassembly and assembly sequence walks through the cylinder head, crankcase, drive gear, air cylinder, clutch housing and pistons, with a warning to remove mounting sealant from the mating surfaces. The troubleshooting section pairs a symptom table with dedicated tests for head-gasket oil leakage, brake-system leakage, discharge and air-dryer temperature, governor operation and clutch charging, and the torque chart specifies values such as 130 to 159 lb-ft on the center-shaft nut.
Applicable truck models
The MCAC 476 is a two-cylinder, water-cooled-head compressor with a 476 cc displacement, 3.74-inch bore and 1.32-inch stroke, driven by the engine and controlled by a mechanical clutch. It weighs about 74 lbs, so removal requires care. Verify coverage against your VIN and build sheet on the International Trucks website.
Who needs the PayStar air compressor manual
Air-brake and charging-system technicians use this manual to rebuild the MCAC 476, set center-shaft-nut torque (130 to 159 lb-ft) and diagnose slow air build-up, clutch malfunction or oil carryover on International vocational trucks.
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