Where to Find the S/N Plate on a Cat 627B

[MikePhua]

On the Caterpillar 627B scraper, the serial number (S/N) plate for the rear section is located on the left-hand side, just below the draft (hitch) arm and near the pivot point of the machine. The S/N is not only on a metal plate but is also stamped directly into the frame in that same area.
This is based on a technician's input — he described that even when the plate is missing, you can often still read the numbers as they are permanently etched into the frame.

Why This Matters

• Knowing the exact S/N helps when ordering parts, especially for a vintage scraper like the 627B.
  
• For documentation, used-equipment sales, and machine history, having that S/N confirms the machine’s identity.
  
• When troubleshooting or repairing, referencing the correct serial number ensures you look at the right service manual and parts list.
  

Tips for Locating the Serial Number

• Clean the left frame area under the hitch arm — rust, dirt, or paint often hide stamped numbers.
  
• Use a flashlight at an angle — the stamp may be shallow but visible when highlighted correctly.
  
• If you can’t find the original plate, having the stamped number is usually acceptable for parts orders and machine registration.
  

Terminology Explained

• S/N Plate: A metal tag affixed to the machine frame that shows the serial number.
  
• Stamped Serial: Serial number pressed directly into the metal frame, not on a separate tag.
  
• Draft Arm: The scraper’s front hitch component used to connect to a pull or push tractor.
  

Conclusion
If you’re looking for the serial number on a Cat 627B’s rear section, check below the draft arm on the left side. Even if the identification plate is missing, the number is likely still stamped into the frame. This makes it possible to confirm your machine’s identity for maintenance, parts, or resale — just be ready to clean and shine a light to read it properly.