How to Replace a Belt for an Air Compressor

by Tim McMahon
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Back in the old days, replacing a belt on an air compressor was simple because the belt was out in the open. But these days, with all the safety protection in the way, you can't even see the belt. Even so, the process is still pretty straightforward and can be accomplished quickly with a minimum of effort.

Air Compressor Belt Replacement

Step 1

Remove the belt guard. The safety housing around the belt and pulleys is usually bolted to the base and reinforced by one or more brackets. To remove it, first loosen the bolts holding it to the base and remove any attached support brackets.

Step 2

Remove the old belt. If it has snapped entirely in two it is easy to remove. If it is just frayed or worn you will need to loosen the motor from the base and slide it toward the compressor to get the belt free.

Step 3

Determine the replacement belt size your compressor needs. If the belt isn't broken it will be easier to determine the best belt replacement size. Some auto supply stores have belt measuring devices that tell you the size. If your belt is broken, it is more difficult to determine the precise size. You might need to look at the owner's manual or manufacturers website to determine the proper size belt for your compressor.

Step 4

Install the new belt on your compressor by placing it over the motor pulley and compressor pulley. The screws holding the motor should be loose, and the motor should be slid as close to the compressor as the slots will allow. If the belt is too tight, do not try to force it. You might cut the inside of the belt, causing it to thump with every turn and quickly break again.

Step 5

Slide the motor away from the compressor to tighten the belt. You might need a block of wood or an assistant to help hold it taught while you tighten the bolts that hold the motor.

Step 6

Test the tension of the belt by pressing down in the center between the two pulleys. The belt should be able to be depressed about 1/2 inch. If it is too tight it can burn out the bearings on the motor or compressor. If it is too loose the belt might slip and wear out, or not turn the compressor.

Replace the belt guard, support brackets and attaching bolts. Make sure they are all tight. Air compressors experience a lot of vibration that can cause screws to loosen if not tightened properly. Plug in your compressor and the job is finished.

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