It is important before starting this or any other procedure, that you or anyone who operates, works with, maintains, services or repairs the Butler System and/or vehicle, be familiar with its operation and thoroughly read, understand and follow, in their entirety, all of the Warnings, Cautions, and Notices described in your Butler System and vehicle Owners’ Manuals.
Carefully read and understand the complete list of instructions before proceeding.
Purpose: Install, or replace, and adjust, the Butler System Crankshaft Pulley.
Applicable Models: 2003+ Chevrolet, GMC vans and cut-aways, and Isuzu NPR and NQR cab-over trucks with 4.8l, 6.0l, and 6.6l V8 Gas engines.
IMPORTANT: Use only a Butler System Crank Pulley with a YELLOW label. Pulleys identified with a YELLOW label are adjustable and require the following procedure to complete the proper installation. Failure to properly adjust (align) the pulley may result in engine vibration and possible damage to the vehicle and/or Butler System.


Magnetic mount travel dial indicator can be borrowed from The Butler Corporation upon request.

2. Mount magnetic dial indicator to suitable position. (Suggested dial indicator position for 2003-2020 6.0L & 4.8L V8 engines shown below.)

2a. 2021 and newer vehicles with 4.3L V6 & 6.6L V8 engines must use the dial indicator mounting plate available to rent in our crankshaft drill kits and dial indicator kits.(Suggested dial indicator mounting position shown below.)


3. Dial indicator reading should be taken at the front ring of the Butler pulley.
4. Using ½" drive ratchet, 3" extension and 1" socket rotate the engine crankshaft clockwise one complete revolution.
5. Note the highest and lowest reading of the dial indicator. Subtract the lowest reading from the highest reading to determine the total dial indicator movement.

6. Continue rotating engine crankshaft clockwise until the lowest point on the pulley is shown on the dial indicator.

7. Gently tap the pulley towards the dial indicator moving the pulley 50% of total movement noted above (line 5).
8. Example: if total movement noted was .020in you need to tap pulley towards center .010in

9. Rotate engine crankshaft clockwise again noting total dial indicator movement. Total dial indicator movement should be less than .010in, if not repeat steps 3 through 5.
10. Tighten the four pulley bolts to 37lb-ft.
11. Rotate engine crankshaft clockwise again. Total dial indicator movement should remain less than .010.
12. Remove the dial indicator.
13. Install (2) new Butler V belts.
14. Install fan clutch assembly and torque to 70lb-ft.
15. Install upper fan shroud.
16. Install air cleaner.
17. Install coolant reservoir.
18. Connect negative battery cable.
19. Start engine and inspect for any abnormal engine or Butler System Driveshaft vibrations.
If you have any questions, please call the Butler Corporation Service Department at (800)535-5025.
Butler System Crankshaft Pulley Installation & Replacement 20211209
The Butler Corporation is a family-owned American business, providing factory direct sales, service and support to thousands of cleaning and restoration professionals in all fifty states, as well as, Canada, Bermuda, Cayman Islands, Puerto Rico, St. Maarten and various U.S. government agencies worldwide.
"The Butler System is especially appreciated by customers who work in extreme conditions, operate their business in remote locations or where dependable local service is not available."
When you invest in a Butler System you do so knowing with confidence that you will always receive factory direct service and support.
