How to Properly Install a Pulley with a Bushing on Your Air Compressor Motor

Installing a motor or engine pulley may seem simple, but getting it right—especially when it includes a bushing—is essential for your air compressor's long-term performance, safety, and smooth operation.

Whether replacing a worn pulley or installing one for the first time, here's a step-by-step guide to help you do it properly.

1. Clean the Components Thoroughly

Before installing anything, ensure that the shaft, bushing bore, and pulley hub are clean and free of:

• Dirt or debris
  
  
• Grease or oil
  
  
• Burrs or rust
  
  

Use an emery cloth if needed to get a smooth surface. A clean fit is essential for proper alignment.

2. Install the Key and Position the Bushing

• Insert the key into the shaft keyway. If the bushing comes with a key, you must use that specific key—it may be specially designed for fit and alignment.
  
  
• Carefully open the bushing saw cut just enough with a screwdriver blade to help it slide onto the shaft. Caution: Do not over-expand, as this can cause the bushing to crack.
  
  

Slide the bushing onto the shaft with the flange facing the equipment, then lightly tighten the set screw to prevent it from sliding.

3. Mount the Pulley and Align Holes

• Place the pulley onto the bushing.
  
  
• Align the drilled holes in the pulley hub with the tapped holes in the bushing flange.
  
  
• For M through S style bushings, ensure the two tapped removal holes in the pulley are as far from the saw cut as possible.
  
  
• Insert and finger-tighten the cap screws.
  
  

4. Tighten Gradually and Evenly

Using a crisscross or star pattern, gradually tighten the cap screws in sequence. Avoid over-tightening one side first—this can cause misalignment or even damage.

5. Torque the Screws Properly

Using a torque wrench, apply the specified torque (check the manual or manufacturer recommendations). This ensures even pressure and a secure fit that won’t loosen over time.

Need a New Pulley?

We carry a wide selection of motor pulleys for air compressors—browse the full lineup here: Master Tool Repair Pulley Selection

Proper installation ensures quieter operation, less vibration, and longer-lasting performance. If you’re unsure which pulley or bushing you need, our team is here to help!