How to Bleed the Clutch on a Semi Truck

Bleeding the clutch on a semi truck is a process similar to bleeding brakes on a car. It’s generally consistent across most hydraulic clutches, regardless of the truck's make or model. Follow these steps to properly bleed the clutch on your semi truck:

Steps to Bleed the Clutch

1. Fill the Reservoir

   • Ensure the clutch/brake fluid reservoir is filled to the maximum level with the appropriate fluid.

2. Locate the Bleed Fitting

   • Find the bleed fitting, typically located on the transmission near the slave cylinder housing. Attach a clear, airtight hose to the fitting, and submerge the free end of the hose in a container filled with enough clutch/brake fluid to cover the hose end.

3. Pump the Clutch Pedal

   • Press the clutch pedal 10-15 times. If there is air in the system, the pedal may not feel firm; continue pressing it for a total of 15 strokes.

4. Hold the Pedal Down

   • Fully press the clutch pedal to the floor and hold it there.

5. Release Air from the System

   • Unscrew the bleed fitting. Watch for air bubbles moving through the hose. Once the air bubbles stop, tighten the bleed fitting back up.

6. Repeat the Process

   • Release the clutch pedal and repeat steps 3-5 until no more air bubbles appear in the fluid exiting the bleed fitting.

Pro Tip for Shop Environments

To speed up the process in a shop setting, you can create an air adapter from an old clutch reservoir cap. Apply a minimal amount of air pressure to the system. Use this method cautiously and at your own risk, as improper pressure can damage the system.