The Rotary FC5797-TH-UN seal kit is the direct replacement for the Rotary lift it came off of. Cross-referenced as ALS-7531-42U, it is the genuine Rotary part — same part number, same fit, and same working specification as the one already on your lift. Ordering the Rotary seal kit from us gets you the OEM piece that matches the lift, not an aftermarket knock-off that is close but not the same.

Specifications

• Part number: ALS-7531-42U
• Brand: Rotary
• Type: Genuine OEM seal kit
• Fits: AR122EL1, AR122EL2, AR122L, AR123, ARO123, SM123
• Lift type: 4-post lift

Hydraulic parts fit by the numbers, and the numbers are unforgiving. A cylinder has to match working length and port type; a hose is spec'd by inner diameter, pressure rating, and end fittings; a power unit lives or dies on voltage. Even seal kits differ by who built the cylinder — the same lift model can carry two cylinder brands with different seal profiles. Order to the actual part, not the lift name.

No hydraulic part works alone. A cylinder is only as good as the fluid feeding it, the fluid is only as clean as the reservoir and filter keep it, and a fresh seal kit won't hold in a barrel that's already scored. That's why a leak is worth diagnosing as a system: replace the weeping part, but check the fluid, the fittings, and the bore before you call it fixed.

What lifts this seal kit fits

This seal kit fits the lift models below. Click a model to open its visual parts breakdown — the exploded drawing with every part numbered, so you can confirm this is the right part for your exact lift before you order.

• AR122EL1 — see the exploded parts breakdown for this lift
• AR122EL2 — see the exploded parts breakdown for this lift
• AR122L — see the exploded parts breakdown for this lift
• AR123 — see the exploded parts breakdown for this lift
• ARO123 — see the exploded parts breakdown for this lift
• SM123 — see the exploded parts breakdown for this lift

Related parts for this lift

The parts below are commonly ordered alongside this one — cables, sheaves, seals, and hardware wear on similar schedules, and most repairs go faster when the whole set is done in one visit.

• Seal Kit for Texas Hydraulic FC5797 - Rotary FC5797-TH
• Hydraulic Cylinder - Rotary FC5818-18
• Hydraulic Cylinder - Rotary FC5810-38
• Seal Kit - Rotary FC5810-38-12TH
• Lower Cylinder Shaft - Rotary - FC5818-32
• Seal Kit - SM301 - Rotary - FC5761-12TH

Replacing your seal kit

Replacing a hydraulic cylinder comes down to relieving all pressure, capping the lines so nothing gets contaminated, getting the old cylinder out and the new one in, then bleeding the air and leak-checking under load. The exact removal path differs by lift style, and skipping the bleed leaves the lift spongy. Because a cylinder holds a vehicle in the air, the full procedure is worth following start to finish. Full step-by-step: how to reseal a lift cylinder.

Find the right part for your lift

Not certain this is the exact part your lift needs? Start with your lift's model and serial off the data plate, then open our Rotary parts lookup to see the visual parts breakdown for your model — the exploded drawing with every part numbered and priced. If your plate is missing or unreadable, our guide to finding your model number walks through where to find it, or send us a photo and we will identify the lift for you.

Signs of a hydraulic problem

For a seal kit specifically, the decision is made inside the barrel. Before you order seals, confirm the bore isn't scored and the rod isn't pitted where the seal rides — new seals won't hold in a damaged cylinder. Shine a light down the barrel; smooth and shiny is good, scratched or rust-pitted means the cylinder itself needs replacing, not just seals.

Parts commonly replaced at the same time

Hydraulic parts travel in company: a leaking cylinder often needs a seal kit, a tired hose, and a fluid change all at once. Since you are relieving pressure and bleeding anyway, do the related wear items in the same visit. Tell us your model and we will pull the matching seals, hose, and oil.

Hydraulic fluid

Fluid matters on any hydraulic repair: most lifts take an ISO-32 hydraulic oil, though a number of older ones spec Dexron ATF. Match whatever is already in the reservoir rather than mixing types, and top off to the level your manual specifies after bleeding — capacities differ from model to model.

Safety notes

The failure mode that hurts people is slow drift-down from a bad seal or trapped air, so never leave a hydraulic repair half-bled. Support the lift on its mechanical locks while you work, relieve pressure before opening the system, and cycle it several times empty — watching for drift — before a vehicle goes on it.

Before you order

A little prep prevents a wrong order: confirm model and serial, measure hoses and note fitting sizes, and check whether a reseal solves it before buying a complete cylinder. Budget for oil and bleeding as part of the repair. We will confirm the right part for your production run before it ships.

Ordering the right revision

Before this goes in the cart, grab two things off your lift: the model number and the serial number, both on the manufacturer's plate. The serial matters more than most people expect — lift makers revise components between production runs without renaming the lift, and the run your serial falls in determines which revision of this part is correct.

If you are working from a failed part rather than a plate, measure what you have and photograph how it mounts. Send that to us along with the lift brand, and we will check it against the same parts breakdowns our own techs use in the field before you commit to the order.

Why buy your Rotary seal kit from Auto Lift Services

We install, inspect, and repair Rotary lifts every week — the ALS-7531-42U is a part we handle in the shop, not a random SKU we drop-ship. The phone answers if you have a question mid-install — call 800-674-9302 — and every part ships genuine, no aftermarket substitution unless you ask for it.