Q: What is the correct way to adjust a heavy duty clutch?
A: First, you need to know what “properly adjusted” is. All HD 15.5” pull style clutch manufacturers, both OE first fit and aftermarket, will tell you that the proper distance of the clutch release bearing and the clutch brake is a minimum of 1/2". This is the SAE standard, and this distance is required to allow the clutch to properly release. Also, this is the standard position for manual and automatic adjust clutches and manual or hydraulic clutch release linkage. None of the manufacturers will tell you to start with the clutch pedal in-cab “free play.”
Manual Clutch Adjustment: For a manual adjust clutch, the technician would use the clutch adjustment features to set the release bearing to clutch brake distance to 1/2". Second, check to ensure the release bearing to release fork distance is 1/8". Then, check the clutch brake squeeze by depressing the clutch pedal in the cab to the floor and verifying that the release system can stroke the clutch release bearing all the way to the clutch brake and stop the input shaft from turning. Lastly, check in-cab free play. In-cab free play is the final result of proper clutch adjustment.
Self-Adjusting Clutches: For a self-adjusting clutch, like the Eaton Solo, the procedure is similar. Confirm the 1/2" measurement from the release bearing and the clutch brake. Check for a 1/8" gap between the release fork and release bearing. Next, check the clutch brake squeeze by depressing the clutch pedal in the cab to the floor and verifying that the release system can stroke the clutch release bearing all the way to the clutch brake and stop the input shaft from turning. Finally, check in-cab free play. In-cab “free play” is the final result of proper clutch position and adjustment.
Information provided by: Betts Truck Parts & Service
