Case Cylinder Pistons - 1-Pc vs. 2-Pc

During production of some popular Case equipment models, like the 580B & 580C Backhoes, Case was transitioning from using a 2 piece piston with V-stack type seals in their cylinders to a 1 piece piston with more modern seals.

For most models there is no clean serial number break to let you know when they switched. This makes it more difficult to know which seal kits you need for your equipment. We’ve put together the image above and the guide below to help.

Example of a 1 Piece Piston

Case 1 Piece Piston - Case Single Piston | HW Part Store

Example of a 2 Piece Piston

Case 2 Piece Piston - Case Split Piston | HW Part Store

There are 2 ways to distinguish which type of piston is in your cylinder

  1. Disassemble the cylinder and check the piston itself


  1. Find the cylinder number stamped on the top of the gland (where the rod comes out of the barrel).

If the cylinder number starts with a D or G3 then it uses a two piece piston and will require a 2-Pc Piston Seal Kit. (Exception: Cyl. # G33128 is 1 piece).

If it starts with G10, A, or any number then it uses a one piece piston and requires a 1-Pc Piston Seal Kit. (Exception: Cyl. # G100414 & G100415 are 2 piece).


Gilberto Rodriguez

Gilberto Rodriguez

Great info I’ll be ordering as soon as I check # s on cylinders job



once again you folks have done a great job in helping a “non-pro” repair a cylinder….fast shipping and great phone response (even though they don’t have their phone # listed on your shipping/receipt…lol)…left a message and they called me back within a few minutes….MORE companies could take a lesson from these folks on how “real” customer service should be…

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