Buying a Hydraulic Arm Cylinder: What to Know

If you need a hydraulic arm cylinder — for a excavator, a loader, a dump trailer, a crane, or any other hydraulic equipment — you're probably replacing a broken cylinder, or building something new. Hydraulic cylinders are the muscle of hydraulic systems, and they're built to take a lot of abuse. But when they break, you need to replace them, or repair them. Here's what you need to know.

New, Used, or Rebuilt?

When you need a hydraulic arm cylinder, you have three options:

Buy New. This is the most expensive option, but it's the best option if you need a warranty, or if you can't afford downtime. New cylinders come from the original equipment manufacturer (OEM), or from aftermarket manufacturers. They're built to spec, and they come with a warranty. But they're expensive — a big excavator arm cylinder can cost $1,000 to $5,000 or more.

Buy Used. This is the cheapest option, but it's risky. You can find used cylinders at salvage yards, or on eBay. But you don't know how much life is left in them. They might be good, or they might be about to fail. If you're on a tight budget, and you know what you're doing, used cylinders can be a good deal. But if you're not sure, it's risky.

Rebuild Your Old Cylinder. This is the middle option. Instead of buying a new cylinder, you can take your old cylinder to a hydraulic shop, and have it rebuilt. They'll replace the seals, the wipers, the bearings, and any worn parts. Rebuilding is usually 30-50% cheaper than buying new. And you know exactly what you're getting, because it's your own cylinder. If the cylinder body and the rod are in good condition, rebuilding is a great option.

What to Look For When Buying a Hydraulic Cylinder

When you're buying a hydraulic arm cylinder, check these things:

- Bore size: The bore size is the diameter of the inside of the cylinder. That determines how much force the cylinder can produce. You need to get the right bore size — if it's too small, the cylinder won't have enough power. If it's too big, it will be too slow, and it will use too much hydraulic oil.
- Rod size: The rod size is the diameter of the piston rod. You need to get the right rod size, too. If the rod is too thin, it will bend under load.
- Stroke length: The stroke length is how far the cylinder extends. You need to get the right stroke length — that's how far the arm can move.
- Mounting style: How is the cylinder mounted? Clevis mount, flange mount, trunnion mount, or something else? You need to get the right mounting style, to fit your equipment.
- Pressure rating: What's the maximum pressure the cylinder can handle? Make sure it's rated for your system pressure.
- Port size: What size are the hydraulic ports? Make sure they match your hoses and fittings.

FAQ

Q: How much does a hydraulic arm cylinder cost?
A: It depends on the size and the type. A small cylinder for a dump trailer costs $100 to $500. A medium cylinder for a skid steer loader costs $300 to $1,000. A big cylinder for an excavator costs $1,000 to $5,000 or more. Rebuilt cylinders are 30-50% cheaper. Used cylinders are 50-70% cheaper.