Usage:
Air Induction
One of the single most important aspects of compressor preventive maintenance is the induction of clean air. The type and interval of maintenance required will vary depending upon the air induction system used.
The intervals listed under the headings below pertain to typical highway and street operation. More frequent maintenance will be required for operation in dusty or dirty environments.
Polyurethane Sponge Strainer
Fig 10 Polyurethane Sponge Strainer
Every month, 150 operating hours or 5,000 miles, whichever occurs first, remove and wash all of the parts. The strainer element should be cleaned or replaced. If the element is cleaned, it should be washed in a commercial solvent or a detergent and water solution. The element should be saturated in clean engine oil, then squeezed dry before replacing it in the strainer. Be sure to replace the air strainer gasket if the entire strainer is removed from the compressor intake.
Dry Element - Pleated Paper Strainer
Fig 11 Dry Element - Pleated Paper Air Strainer
Every two months, 800 operating hours or 20,000 miles whichever occurs first, loosen the spring clip from the unhinged side of the mounting baffle and open the cover. Replace the pleated paper filter and secure the cleaned cover, making sure the filter is in position. Be sure to replace the air strainer gasket if the entire air stainer is removed from the compressor intake.
Intake Adapter
When the engine air cleaner is replaced; Some compressors are fitted with compressor intake adapters, which allow the compressor intake to be connected to the engine air induction system. In this case, the compressor receives a supply of clean air from the engine air cleaner. When the engine air filter is changed, the compressor intake adapter should be checked. If it is loose, remove the intake adapter, clean the strainer plate, if applicable, and replace the intake adapter gasket, and reinstall the adapter securely. Check line connections both at the compressor intake adapter and at the engine. Inspect the connecting line for ruptures and replace it if necessary.
Compressor Cooling
Every 6 months, 1800 operating hours or after each 50,000 miles whichever occurs first, inspect the compressor discharge port, inlet cavity and discharge line for evidence of restrictions and carboning. If excessive buildup is noted, thoroughly clean or replace the affected parts and closely inspect the compressor cooling system. Check all compressor coolant lines for kinks and restrictions to flow. Minimum coolant line size is 3/8 inch ID. Check coolant lines for internal clogging from rust scale. If coolant lines appear suspicious, check the coolant flow and compare to the tabulated technical data present in the back of this manual. Carefully inspect the air induction system for restrictions.
Lubrication
Every six months, 1800 operating hours or 50,000 miles which ever occurs first; check external oil supply and return lines, if applicable, for kinks, bends, or restrictions to flow. Supply lines must be a minimum of 3/16 inch ID and return lines must be a minimum Of 1/2 inch ID. Oil return lines should slope as sharply as possible back to the engine crankcase and should have as few fittings and bends as possible. Refer to the Tu-Flo 550 Specifications section for specific requirements.
Compressor Drive
Every six months, 1800 operating hours or 50,000 miles, whichever occurs first, check for noisy compressor operation, which could indicate a worn drive gear coupling, a loose pulley or excessive internal wear. Adjust and/or replace as necessary.
If the compressor is belt driven, check for proper belt and pulley alignment and belt tension. Check all compressor mounting bolts and retighten evenly if necessary. Check for leakage and proper unloader mechanism operation. Repair or replace parts as necessary.
Every 24 Months, 7200 Operating Hours Or After Each 200,000 Miles; perform a thorough inspection, and depending upon the results of this inspection or experience, disassemble the compressor, clean and inspect all parts thoroughly, replace all worn or damaged parts using only genuine replacements or replace the compressor with a genuine remanufactured unit.
General Service Checks Operating Tests
Vehicles manufactured after the effective date of FMVSS 121, with the minimum required reservoir volume, must have a compressor capable of raising air system pressure from 590 to 700 kPa (85 to 100 psi) in 25 seconds or less. This test is performed with the engine operating at maximum recommended governed speed. The vehicle manufacturer must certify this performance on new vehicles with appropriate allowances for air systems with greater than the minimum required reservoir volume.
Air Leakage Tests
Compressor leakage tests need not be performed on a regular basis. These tests should be performed when; it is suspected that discharge valve leakage is substantially affecting compressor build-up performance, or when it is suspected that the compressor is "cycling" between the load and unloaded modes due to unloader piston leakage.
These tests must be performed with the vehicle parked on a level surface, the engine not running, the entire air system completely drained to 0 psi, and the inlet check valve detail parts removed, if applicable.
Unloader Piston Leakage
The unloader pistons can be checked for leakage as follows: with the cylinder head removed from the compressor and the inlet flange securely covered, apply 825 kPa (120 psi) of air pressure to the governor port. Listen for an escape of air at the inlet valve area. An audible escape of air should not be detected.
Discharge Valve Leakage
Unloader piston leakage must be repaired before this test is performed. Leakage past the discharge valves can be detected as follows: Remove the discharge line and apply shop air back through the discharge port. Listen for an escape of air at the compressor inlet cavity. A barely audible escape of air is generally acceptable.
If the compressor does not function as described above or if the leakage is excessive, it is recommended that it be returned to the nearest authorized distributor for a factory remanufactured compressor. If it is not possible, the compressor can be repaired using a genuine cylinder head maintenance kit. Retest the cylinder head after installation of the kit.