Quick take
When a backhoe cylinder starts leaking or a water pump drips, you need the right seal, gasket, or o-ring fast-but the options here are very different. There's a cylinder-specific kit for Case backhoe dippers, a two-piece mechanical seal for water pump shafts, a Buna-N o-ring set in a standard size, and a metric o-ring assortment for mixed repairs. The smart move is to match the product to the exact job: a kit for a known cylinder, a shaft seal for a pump, a standard o-ring for a known dash size, or an assortment for general shop use.
Price comparison
| Product | Price | Price bar | Best for |
|---|---|---|---|
| Case 580K/580SK/580SL Backhoe Dipper Hydraulic Cylinder Seal Kit | USD 35.00 | Case dipper cylinder rebuild | |
| Zaplyte Water Pump Mechanical Seal (2 Pcs, 10mm) | USD 14.59 | 10mm water pump shaft | |
| AS568-235 Buna 70 Duro O-Ring Set (Qty 25) | USD 20.00 | Standard o-ring spares | |
| O-Ring Assortment Kit (400 Pc, Nitrile Metric) | USD 12.74 | Mixed metric o-ring jobs |
Decision matrix
- If the repair is a backhoe dipper cylinder, the Case seal kit is the only fitment-specific option here. It lists rod and bore dimensions and references OEM cylinder numbers, so it removes the need to match individual seals.
- If you need to reseal a water pump or submersible pump shaft, the Zaplyte mechanical seal is built for a small shaft seal replacement with a single coil spring and rubber bellows.
- If you need a known standard dash size for hydraulic, pneumatic, automotive, fuel, or oil sealing, the Buna-N set is a practical pack for that size.
- If you want one box to cover many o-ring jobs, the assortment is the broader shop solution.
Product notes
Case Backhoe Dipper Hydraulic Cylinder Seal Kit
This kit is for the dipper cylinder on Case Loader/Backhoe models 580K, 580 Super K, and 580 Super L. It is new and specifies a 2.50 inch rod and 5.00 inch bore, with OEM cylinder numbers like 126151A1 and 183795A1 for fitment. If you are rebuilding one of those cylinders, this is the most direct choice: you get the seals for that cylinder instead of hunting through an assortment. The flip side is that it is not a general-purpose kit. It is tied to those Case models and cylinder numbers, so it will not cover water pump shaft seals or unrelated o-ring sizes.
Zaplyte Water Pump Mechanical Seal
This two-piece mechanical seal is sized for a 10mm internal diameter water pump or submersible pump shaft. It uses a single coil spring and rubber bellows, and the materials are carbon, rubber, and metal. That makes it a simple, targeted replacement when you have a 10mm shaft and want a seal made for that bore. The catch is that it is not an o-ring set or a cylinder kit. The 22 x 29mm overall size is specific, so it is meant for a small shaft seal application rather than broad industrial sealing. It also carries a California Prop 65 warning.
AS568-235 Buna 70 Duro O-Ring Set
This pack gives you 25 AS568-235 standard Buna-N o-rings, a common size for hydraulic, pneumatic, automotive, fuel, and oil sealing. The 70 durometer hardness is stated, so it is easy to match against a standard Buna-N application. Because it is one dash size, it is best as a spare-part refill for a size you already use. The downside is that it is not a multi-size assortment; other dash numbers and metric sizes are not in the pack. If your job calls for a different o-ring size, this set will not solve it.
O-Ring Assortment Kit 400Pc Nitrile Rubber Metric Sizes
This is the broadest-coverage product in the group: 400 black nitrile o-rings in metric sizes from 4mm to 30mm outside diameter, with thickness options of 1mm, 1.5mm, 1.9mm, 2.4mm, and 3.1mm. The rings are stored in a labeled, resealable container, which makes them easy to sort through for plumbing, automotive, or general repair. The trade-off is that it is a general assortment, not a cylinder-specific kit or a shaft seal. It will not replace the Case dipper kit or the Zaplyte water pump seal, and you still need to choose the right size within the pack.
Final recommendation by use case
For a one-job backhoe dipper cylinder rebuild, the Case cylinder seal kit at USD 35.00 is the fitment-specific pick. For a water pump shaft, the Zaplyte two-pack at USD 14.59 matches that exact application. For a standard o-ring size in quantity, the Buna set at USD 20.00 gives you a practical spares pack. For mixed metric repairs and the widest coverage at the lowest price in this group, the O-Ring Assortment Kit at USD 12.74 is the grab-and-go choice.
