How to Repair Air Compressor

You may have air compressor or seen it before. At the first time itself, we will notice that it is difficult to troubleshoot and repair by its complex construction. So, here are going to give you some methods to make your best air compressor healthy for long time and to keep your money in your pocket itself.


 I. Safety First!

You must remove power and purge the tank of air before proceeding with the air compressor overhaul. Removing power is easy; just unplug it from the wall outlet. Purging the tank may not be as self-evident. In order to purge the tank pull the ring on the safety valve (circled in picture). If the tank is partially full the sound of the rushing air can be deafening as it rushes out of the ports of the safety valve so be warned!

II. Setup a Work Area

Set up a proper work area when working on your air compressor. I used a couple of folding tables we have around for parties. Assemble all tools required and also plastic containers to hold discrete parts. In addition, a can of WD40 spray lubricant, paper towels, and I spray bottle with water to check for air leaks is essential.

III. Remove Compressor Shroud

The motor and compressor assembly is enclosed in a two piece plastic shroud. The smaller front shroud is attached to the compressor using two Torx screws. The rear shroud is attached to the motor with one Torx screw. The front and rear shroud join together with built-in clips. The shroud serves several purposes. It keeps you from touching the air compressor head which can get hot during use. It protects you from getting cut from the blades of the built-in cooling fan, and isolates you from contact of electrical parts such as the motor and starter capacitors.

IV. Remove the Compressor Head

Remove the compressor head, circled in red. It is held in place with four bolts. The black plastic piece to the right is called the muffler. It is where the air enters the compressor. I believe that it “muffles” the sound of air rushing into the air intake.

V.Valve Plate Assembly Removal

Removal of the compressor head exposes the valve plate assembly. This allows air to enter the compressor but prevents it from escaping through the muffler intake.

VI. Valve Plate Assembly Inspection

Dissemble the valve plate assembly. The metal reeds are held in place by small bolts. Check the reeds for warping or cracking. They need to provide a good seal against the valve plate in order for your air compressor to reach maximum pressure.

VII. Fan Removal

The fan connects to the end of the motor shaft and is held in place with one bolt. You need to remove the fan in order to loosen the bolt that holds the connecting rod onto the shaft.

VIII. Connecting Rod and Cylinder Sleeve Removal

Once the fan is removed, the connecting rod can be removed from the bearing with one bolt at the base. The cylinder sleeve is held in place by the valve guide and head. Since the head and valve guide are removed, the cylinder sleeve can be easily removed by pulling it straight up and out. Once the cylinder sleeve is removed, the connecting rod can be pulled off. Under the connecting rod is a counterbalance weight. It is important to observe the orientation of the counter balance weight in relation to the connecting rod, over-wise, excessive vibration will occur.

IX. Cylinder Sleeve Inspection

Inspect the cylinder sleeve for damage. It is quite obvious that the walls of this cylinder sleeve has scratches, scoring, and should be replaced.

X. Replacing the Connecting Rod and Cylinder Sleeve

Most Connecting Rod and Cylinder Sleeve kits come with replacement gaskets used between the head and cylinder. In addition, detailed instructions including bolt torque specs.

XI. Reassembly

Reassembly of your air compressor is pretty straight forward. Just follow the steps above in reverse order and your vintage air compressor will function like the day it was purchased. Please note, it is important to replace the cylinder and head gaskets during the reassembly process.

XII. Testing

It is important to test your rebuilt air compressor after reassembly. Plug it in, power it on and let it get up to peak tank pressure. Once up to tank pressure turn it off at the pressure switch and unplug it from the wall outlet.

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