Boss Hydraulic Air Compressor BA440

First, shut down the machine and allow it to cool for at least 10 minutes. Verify that the entire system is pressure relived before proceeding. Next, remove the bolts and lift off the pump cover. Use a single edged razor blade or putty knife to remove the old gasket material, but make sure not to damage the machined surfaces.

Lift the pump out of the cavity and position a new gasket on the rear bearing housing. Next, insert the pump into the cavity and position it slightly to one side using a common screwdriver. Wedge the pump into he piston so that it partially compresses the spring. Note that the driver pin and slot in pump must be in line.

Next place the pump cover into position and start two bolts. Strike the pump cover with a rubber mallet to jar the pump loose. When the tension spring can be felt against the pump cover, the pump is lose. Now you can insert the two remaining bolts and torque to 180 in-lbs. The bolts should be torqued in a diagonal pattern. Finally, install the air compressor in the vehicle and connect air lines and wiring.

Crankshaft and Bearing Replacement

If it is necessary to replace the crankshaft, related components must also be replaced. Replace both bearings, both races, the key, pump collar, and pump drive pin.

First, shut down the machine and allow it to cool for at least 10 minutes. Verify that the entire system is pressure relived before proceeding. Remove both heads, cylinders, and pistons (See Piston Ring Replacement on pg. 16).

Next, remove the bolts on the connecting rods and lift them out. Reassemble the connecting rods to be certain that the matched parts remain together on the same crankshaft journals.

Now remove the pump cover, oil pump, sleeve, spring, and rear bearing housing. Next remove the drive hub and the front bearing housing. Next pull the crankshaft from the crankcase and remove all gasket material with a razor blade or putty knife.

Compressor Oil Fill, Level, and Drain

Before adding or changing compressor oil, make sure that the compressor is completely relieved of pressure. Oil is added at the fill cap on a pipe on the rear of the crankcase. A drain line is located on the rear panel of the machine. Proper oil level is to the “FULL” line on the dipstick, when the unit is shut down and has had time to settle. The machine must be level when checking the oil. DO NOT OVERFILL. The oil capacity is given in “Compressor Specifications”.

Changing the Air Intake Filter

The air intake filter is a heavy-duty dry type high efficiency filter designed to protect the compressor from dust and foreign objects.

Frequency of maintenance of the filter depends on dust conditions at the operating site. The filter element must be serviced when clogged. A clogged air filter element will reduce compressor performance and cause premature wear of components.

Changing the Hydraulic Oil Cooler

The interior of the oil cooler should be cleaned when the pressure drop across it at full flow exceeds 25 PSI. First, remove the cooler. Then, circulate a suitable solvent to dissolve and remove varnish and sludge. Then flush the cooler generously with hydraulic oil. Reinstall the cooler. Once the cooler is reinstalled, fill the hydraulic system with the proper fluid to their appropriate levels.

Shut down the machine and allow to cool for approximately 10 minutes. Next, verify entire system pressure is relieved before proceeding. Then, disconnect air inlet system tubes. Now disconnect 3/4” discharge jumper hose and 3/4” discharge hose. Unscrew the head nuts and remove the heads.

1. Inspect the drive coupling for wear.

2. Check the cylinder head stud torque (See NOTE 2)

3. Check the operation of the receiver safety values.;

2. Drain Condensation from air receiver.;