Excavator Cylinder Rebuild — Ames Hydraulics

Excavator Cylinder Rebuild — Boom, Arm, Bucket

Every excavator runs three primary hydraulic cylinders — boom, arm (stick), and bucket — plus auxiliary cylinders for hydraulic thumbs, tilt attachments, and other implements. These are big cylinders. On mid-size excavators they run 4-6 inch bore. On large excavators 6-8+ inch bore. When one leaks, the machine loses digging force or won’t hold the load. Excavator cylinder rebuild is a specialty job that requires heavy bench equipment — which we have.

Our shop is in Ames, Iowa. We do excavator cylinder rebuild on compact excavators (Cat 305/306/308, Deere 30G/35G/50G, Kubota KX/U-series, Bobcat E-series, Takeuchi TB-series), mid-size excavators (Cat 320/323/326/329, Deere 200G/210G/250G, Komatsu PC200/PC210), and large excavators (Cat 336/349/374, Deere 300G/350G/470G, Komatsu PC300/PC350/PC450). Larger machines (400+ class) push the upper limit of our bench capacity — we handle most cylinders in that range but very large main-boom cylinders on the biggest machines sometimes exceed our lift capacity.

Boom Cylinders

The boom cylinder is the biggest cylinder on the excavator’s working end. It carries the entire weight of the boom, arm, bucket, and load. Failure shows up as slow boom lifts, boom drift under load, or oil weeping past the rod. Excavator cylinder rebuild on boom cylinders is a full bench job — pull, disassemble, inspect the rod for pitting, replace all seals, hone the barrel if needed, reassemble with fresh fluid, and pressure test at rated operating pressure. Boom cylinders are heavy — 200-500+ pounds on mid-size machines — and require our bench hoist to move safely.

Arm (Stick) Cylinders

The arm cylinder extends and retracts the arm relative to the boom. It cycles more than the boom cylinder because operators use arm crowd constantly during digging. Failure modes are the same: rod seals, piston seals, rod pitting. Excavator cylinder rebuild on arm cylinders is standard bench work.

Bucket Cylinders

The bucket cylinder curls the bucket to break out material. It has the highest cycle count of any cylinder on the machine. Bucket seal failures are the most common excavator cylinder rebuild we do. The bucket cylinder is also usually the easiest to remove and replace in the field, which is why customers often bring us just the cylinder rather than the whole machine.

Thumb, Tilt, And Auxiliary Cylinders

Excavators equipped with hydraulic thumbs, tilt buckets, hydraulic couplers, or specialty attachments have additional cylinders that come to us for rebuild. Same process — bench work, seal kit, rod service, hone if needed, pressure test. Thumb cylinders in particular take a lot of abuse from operators using them to break material.

Track And Blade Cylinders

Some excavators have track-tensioner cylinders and dozer-blade cylinders. Track cylinders are usually replaced rather than rebuilt because they take low pressure and the parts often cost more than a new unit. Dozer blade cylinders (on compact excavators with front dozer blades) are standard rebuild candidates.

Rod Repair And Replacement

Excavator cylinder rods take heavy abuse. Digging in rocky soil throws grit at the wiper seal. Muddy conditions push contamination past the wiper. Winter road salt attacks the chrome plating during transport. Rod repair is part of most excavator cylinder rebuild jobs. Light pitting we polish on the bench. Deeper pitting requires re-chroming (adds a week). Severely damaged rods we replace — new rods available for most common sizes; specialty rods we fabricate or source.

Cost And Turnaround

Compact excavator cylinder rebuild runs $500-$1,200 per cylinder depending on size and brand. Mid-size machine cylinders run $800-$1,800. Large machine cylinders run $1,500-$3,500. Boom cylinders on the biggest units push $2,500-$4,500. Add $500-$1,500 if a rod needs re-chroming. Add $300-$1,000 for barrel work. Turnaround is 5-10 business days for standard excavator cylinder rebuild, longer for rod re-chrome or specialty parts.

Bench Pressure Testing

Excavators run 3,000-4,000 psi operating pressure. Every excavator cylinder rebuild is bench-tested at rated pressure — extend, retract, hold soak. Any cylinder that fails on the bench doesn’t ship. That’s non-negotiable — sending a bad cylinder back to a working excavator is dangerous.

Independent Scope

We are not a Cat, Deere, Komatsu, Bobcat, or Kubota dealer. We don’t do warranty work. If your excavator is under warranty, use the dealer network. Out-of-warranty excavator cylinder rebuild is our specialty — we’re less expensive than dealer service and we know the machines.

Central Iowa Coverage

Our shop is in Ames, 30 minutes north of Des Moines. Excavator cylinder rebuild customers come from all over Iowa. For contractors within roughly 60 miles of Ames we can arrange pickup and delivery. Cylinders themselves ship well by freight — we get excavator cylinders regularly from Iowa, Minnesota, Nebraska, and northern Missouri.

Common Questions About Excavator Cylinder Rebuild

Can you handle main-boom cylinders from a large excavator? Up to about 400-class machines yes. Very large main-boom cylinders on 500+ class excavators sometimes exceed our bench lift capacity — we evaluate case by case and refer out if we can’t handle it safely.

What if my rod is really damaged? Excavator rods often show deep pitting after years of harsh service. Rod re-chroming through a specialty chroming shop adds a week to the timeline but restores the rod for another decade of service. Rod replacement is available on most common sizes.

Do you rebuild hydraulic thumb cylinders? Yes. Thumb cylinders take heavy abuse from operators pinching material — they show up for excavator cylinder rebuild frequently. Standard bench work.

Do you warranty the rebuild? Yes. Every excavator cylinder rebuild is warranted against seal defects and workmanship for 6 months.

Get A Quote

Call or text 515-292-2599. Tell us the excavator make and model, which cylinder (boom, arm, bucket), and what’s failing. Text a photo of the cylinder and the leak. We’ll ballpark the excavator cylinder rebuild cost over the phone.