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2.5" Piston Kit

  • $57.07
  • or

Koyker OEM Cylinder Part 663318

2 1/2 Cylinder Piston Kit with Packing works with certain Koyker front-end loaders. Completely assembled 2 1/2” OEM Cylinder Piston with all seals.

  • Pistons DO NOT work on other brands of loaders or products.
  • Pistons are manufactured specifically to fit Koyker front-end loaders.

NOTE: This product does not qualify for returns. Confirm correct piston and packing kit by comparing pictures, checking owner's manual AND by measuring the inside diameter of the current piston.

This kit includes the following pieces:

Part Number: K663318 (Assembled)

  • (1) 2 1/2 Aluminum Piston
  • (2) 2 1/2 U-Cup Seals
  • (1) 1 Rod “O” Ring
  • (1) 1" Lock Nut

Related Products:

K662048: 2 1/2" Cylinder Seal Kit
K663317: 2 1/2” Cylinder Gland Kit

Loader Models:

Koyker Loader 220 (Loader may also utilize 2.25" Cylinder Piston Kit)
Koyker Loader 235
Koyker Loader 245
Koyker Loader 310
Koyker Loader 315
Koyker Loader 345
Koyker Loader 385
Legend Loader 542
Legend Loader 640 (Loader may also utilize 3.25 Cylinder Piston Kit)

Download Koyker Loader Manuals

This product does not qualify for returns. Please make sure this product is the correct size and will work for your equipment before purchasing.

Your equipment may consist of NON-OEM parts and may not coincide with product manuals. If you have questions or concerns, please contact our Koyker Customer Service Team at 1-800-456-1107.


Periodically check all hydraulic system connections to insure a leak-free condition. Also, be certain to maintain proper fluid levels in the tractor hydraulic system as in accordance with the method and frequency recommended in the tractor operator’s manual. Use only hydraulic fluids recommended for your tractor hydraulic system by the manufacturer.

Keep hydraulic system clean. Be certain to maintain recommended oil filter service intervals. All internal surfaces of the hydraulic system on your loader have been factory cleaned, inspected, and plugged with protective caps prior to shipment. Be certain all protective caps are securely in place until hydraulic system assembly is completed.

Care must be taken with your loader cylinders. Nicks, scratches, rust or other shaft damage can cause seal damage resulting in cylinder leakage and poor performance.

Read these service tips before beginning assembly of cylinder gland or piston.

  1. Keep seals clean from the time they are removed from package until they are installed.
  2. Clean the groove or bore into which the seal is to be fitted before installing the seal.
  3. Never touch the seal lip in handling. Always pick up the seal by its outer member.
  4. Inspect each seal lip carefully for nicks, scratches, and dirt at time of installation. If dirty, use a soft, clean cloth and carefully wipe off seal. DO NOT wipe seal with fingers as this only imbeds dirt in the seal.

Never clean rubber related seals with a mineral based solvent! Clean rubber seals in denatured alcohol or non-mineral based solvents only.

Seals can be made more pliable and easier to install, if first heated in hydraulic oil to 160 degrees F. Never use direct heat on any seals.

We try our best to ship orders in the timeliest manner possible. Each product may have a different level of manufacturing demand and timeframe for shipment.

Shipping Rates

We offer calculated shipping rates during the checkout process. USPS, UPS & FedEx services are available if the product ordered qualifies for those options.

Order Processing

Business Days: Monday-Thursday.
Holidays, Fridays, Saturdays and Sundays are not included in processing days.

If you have any questions or concerns about your order's status, please email us at to discuss.

International Orders

Customers are responsible for any brokerage fees incurred on shipping. Sioux Steel Company cannot calculate these fees.


Products on this website do not qualify for returns. We understand this may cause you concern....

We are here to help!

Our customer service team is available Monday-Friday, 8am to 5pm CST to discuss the parts in question PRIOR to placing your order.

Call us toll free at 1-800-557-4689 to talk and confirm your parts needed.

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NOTE: All product specifications are subject to change or improvement without notice. We reserve the right to change product pricing at any time without further notice. Pricing may differ at the time of purchase.

Contact Sioux Steel by emailing or by calling our customer service specialists at 1-800-557-4689 for additional information.

SIOUX STEEL COMPANY FOUNDATION: 2% of the total sales dollars from this website are donated to the Leukemia and Lymphoma Society. Beating cancer is in our blood.

Customer Reviews

Based on 9 reviews
Jim Byrd
Good transaction

I needed new seals for my loader. The recommendation to buy already on the piston was worth every extra penny. Entire job took less than 30 minutes, works like a champ.

Michael H.

Excellent packing, shipping and response. The website was a little glitchy but overall very pleased.

Thanks for the feedback!

Jim H.
Piston kit with seals.

The piston kit and seals were exactly what I needed.
Shipping time was good also.

Thanks for the feedback! Have a great day.

Jim H.
Cylinder pistons

Parts were exactly what I needed, great quality and fast shipping.

Thanks for the feedback! Have a great day.

Brian Smith
Perfect fit !!!

The parts sent were a perfect. Only took 1-1/2 hrs to rebuild cylinders in the field. Barb was a great help. Will be ordering seals to rebuild the parts removed in case future wear calls for it.

Thanks for the feedback! Have a great day.

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Ask a Question
  • will koyker part 663318 and 663317 work with k 5 loader with 2.5 '' in side cylinder lift arms

    Thank you for reaching out! With the information you provided, yes, they will work with the K5 loader. If you have any further questions, please feel free to contact our Koyker Customer Service team at 1-800-456-1107.

  • I have 210 loader I need life seal kit will this2.5pistin kit fit

    Thank you for reaching out! I checked with our Koyker Customer Service Team and they let me know that the 210 loader can have either 2” or 2.5” cylinders. To find out which kit you need, you would want to measure the OD of the tube (barrel) and the OD of the shaft. With not offering returns on our kits, we highly suggest that you call our Koyker Customer Service Team with any questions you have with ordering the correct piston kit. They can be reached at 1-800-557-4689 or 1-605-336-1750. Thank you.


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