The hydraulic rotary lift cylinder is the single most expensive part on a two-post lift, and when it fails, the lift is out of service. We are Auto Lift Services in Ames, Iowa, and we handle rotary lift cylinder replacements and rebuild kits for shops across the Midwest. Most of our repair calls in central Iowa — Des Moines, Cedar Rapids, Ames, Ankeny — start with a leaking cylinder or a rod that is rusted or scored. If yours is dripping oil, running slow, or refusing to hold height, this is what you are dealing with.
Hydraulic cylinders and seal kits for Rotary two-post and four-post lifts — stocked in Ames, Iowa.
The hydraulic rotary lift cylinder — how it works and when it fails
On a two-post lift, the rotary lift cylinder is what actually raises the arms. Hydraulic fluid pumped from the power unit pushes a piston up the cylinder bore, the piston drives the rod, and the rod lifts the carriage via a cable-and-sheave system. When the cylinder is healthy, this happens smoothly and holds height reliably. When the internal seals fail, fluid bypasses the piston, the lift runs slow, and eventually the lift stops holding weight.
There are two failure modes. The first is seal wear — a normal, age-related failure, usually fixable with a seal kit. The second is bore or rod damage — a scored rod cuts every new seal you install, and at that point the cylinder needs full replacement. Diagnosing which one you have takes a five-minute inspection of the rod. That inspection saves you hundreds of dollars in the wrong direction.
Seal kits versus full cylinder replacement
The seal-kit-vs-full-replacement decision is the biggest cost lever on a rotary lift cylinder repair. A seal kit for a common Rotary two-post cylinder runs roughly a quarter to a third of the cost of a new cylinder. If the cylinder body is sound and the rod is clean and straight, sealing it is the smart move. That is the difference between a $200 fix and a $700 fix on the same lift.
If the rod is pitted, scored, or bent, skip the seals. A damaged rod will destroy fresh seals within days, and you will be back to square one. The tell is visual: pull the cylinder, wipe the rod down, and look at it under good light. Any grooves, corrosion pits, or side-to-side dents mean the cylinder is done and needs full replacement. We stock both rebuild kits and complete cylinders in Ames for every current Rotary two-post family.
Signs your rotary lift cylinder is on the way out
Six clear symptoms point to a failing rotary lift cylinder. First, the lift runs slower going up than it used to. Second, the lift settles under load — you park a vehicle and come back to find it dropped an inch overnight. Third, fluid weeping around the rod seal or at the base of the cylinder. Fourth, air in the system — spongy feel at the controls, uneven column travel.
Fifth, uneven column heights — one side rises faster than the other, which points to either cable adjustment or one cylinder passing fluid past the piston. Sixth, unusual noise during travel: hissing, groaning, or knocking. Any one of these is a signal to schedule the repair; two or more and you are overdue. Shops in Iowa City, Waterloo, and the Des Moines metro that ignore these signs typically end up with a floor drop, not a controlled repair. Do not let it get to that point.
Matching bore, stroke, and mounting to your model
Ordering a rotary lift cylinder without the model number is a coin flip. Rotary uses different cylinder specs across capacity classes — a 9K lift and a 12K lift do not share cylinders — and even within a class there are variants by production year. Bore diameter, stroke length, port thread, and mounting bracket all have to match the original.
The capacity plate on the column gives us the model and serial we need. From there we can pull the correct catalog number. If the plate is missing, we can measure the existing cylinder — bore is visible with the cylinder retracted, stroke you can measure with a tape at full extension — and match from that. Send us photos and dimensions and we will confirm before the part ships. Working from a good photo is faster and more accurate than working from memory.
Two-post versus four-post cylinder differences
Two-post and four-post Rotary lifts use different cylinders in different roles. On a two-post, cylinders sit inside the columns, one per column, and lift the carriages directly. On a four-post, there is typically a single cylinder that drives a cable-and-sheave system moving all four column carriages together. The mechanics are fundamentally different.
That single four-post cylinder is longer, larger-bore, and higher-capacity than either of the two two-post cylinders. It is also a more involved swap when it fails — the crossbeam has to come off, the cable system has to be reset, and the whole lift needs re-leveling after. Four-post repairs typically involve a full day of shop time, while a two-post cylinder swap can be done in half that. Plan accordingly. See /articles/four-post-lift-repair/ for the four-post-specific process.
What we keep in our essential-parts package
Our essential-parts stocking package for a working shop includes equalizer cables, hydraulic hoses, hydraulic cylinders, and rubber foot pad inserts. Those are the four items that account for the majority of “lift is down, need it today” calls. We keep them on the shelf in Ames so we can ship the same day for shops in Des Moines, Cedar Rapids, Ankeny, Iowa City, Ames, and the surrounding metro areas.
If you run a shop with three or more Rotary lifts, we can put together a stocking package sized to your fleet. That way, when a rotary lift cylinder fails on a Friday afternoon, you are not waiting on freight — you pull the replacement off your own shelf. Ask us about the package the next time you call. It is the cheapest form of downtime insurance a busy shop can buy.
Getting a rotary lift cylinder shipped fast
Downtime on a lift costs money by the hour, so shipping speed matters. When you call us with a cylinder problem, we ask three questions: what is the model, what is the serial, and can you send a photo. With those three, we can pull the right cylinder off the shelf and get it moving inside of an hour. That is the difference between back-in-service tomorrow and back-in-service next week.
We ship out of Ames, Iowa, direct to shops across the Midwest — Des Moines, Cedar Rapids, Iowa City, Sioux City, Council Bluffs, Davenport, Dubuque, and beyond. Same-day dispatch if the order lands before mid-afternoon; overnight to most of the region. Call 800-674-9302, email founder@autoliftserv.com, or start at store.autoliftserv.com. See /articles/rotary-lift-parts/ for the broader parts landscape and /articles/rotary-air-cylinder/ for the pneumatic side.
Our Clients Include: