When a shop needs new rotary lift arms, they usually replace all four at once, because arms wear as a system. We took a call not long ago from a repair shop in north-central Iowa running an SPO12N510 — they wanted a full quote for a set of arms plus inspections on their whole lift fleet. That is a common story. Auto Lift Services is based in Ames, Iowa, and we ship rotary lift arms across the Midwest with same-day dispatch when the order lands before mid-afternoon. From SPOA9 through SPO16, we know the arm families and we keep the popular pins and restraints on the shelf.
Complete sets with restraint gears, pins, and pad inserts — matched to your lift model and serial.
Why shops replace all four rotary lift arms at once
When one arm on a two-post lift has worn out, the other three are usually close behind. Restraint gears, pivot pins, and pad seats wear on a similar cycle, so if you are pulling the lift out of service to swap one, it is dramatically cheaper on labor to swap all four. Every shop we have worked with in Ames, Ankeny, and Cedar Rapids that tried to replace one arm and leave the rest ended up back at us within eighteen months for another set.
The other reason to do all four is safety consistency. Mixed old-and-new arms do not share the same restraint feel, and a tech habituated to a certain click strength on one side will trust it on the other. That mismatch is how side-loading incidents start. Full sets keep the lift consistent and predictable, which is what your inspector and your insurance carrier both want to see when the annual walk-through happens.
Reading your capacity plate before ordering
Every set of rotary lift arms is matched to a specific column capacity, and the way to confirm which set you need is the capacity plate on the column. That plate lists the model number, serial number, rated capacity, and manufacture date. From there, we can spec the correct arm family — symmetric or asymmetric, standard or wide-track, low-profile or full-height. Do not skip this step.
If the plate is illegible or missing, we can identify most Rotary two-posts from column dimensions, pivot geometry, and the shape of the arm restraint housing. Send us photos and we will do the ID work. Trying to guess between a 10K asymmetric and a 12K symmetric arm set will land you with hardware that will not fit or will not safely lift what you are lifting. Do the model-number check first, and if the plate is gone, see /articles/rotary-lift-decals/ for how to get a new one.
The 9K, 10K, 12K, and 15K arm families
The rotary lift arms we ship most often break into four capacity classes. 9K arms fit Rotary SPOA9 and older SPO9 lifts. 10K arms fit Rotary SPOA10 and the current SPO10 platform — this is the volume seller. 12K arms fit the SPO12 and SPO12N — heavier, thicker pins, longer reach range. 15K and up arms fit the SPO15 and SPO16 heavy-duty lifts and get materially larger.
Within each class there are sub-variants — symmetric versus asymmetric loading, standard reach versus long, low-profile versus full. That is why the model and serial number matters so much. A 12K arm from an older SPO12 will not necessarily bolt into a current SPO12N without an adapter or a different pin. When you are ordering, tell us which family your lift is in and what you are lifting; we will match it exactly on the first try.
What comes in a full arm set (and what does not)
A full set of four rotary lift arms typically includes the arm assemblies themselves and the telescoping inner sections. What it does not always include: the arm restraint gears, the pivot pins, the retaining hardware, or the contact pads. Those get sold separately. If you are doing a full arm swap, you want all of that in the same order so you are not standing at the lift missing a $30 pin.
We bundle Rotary two-post arm-replacement kits with the restraint hardware, new pivot pins, and fresh pad inserts, and the total for a mid-capacity lift comes out well under half the price of a new lift. If the columns and hydraulics are healthy, refreshing the arm system is a big-impact, moderate-cost investment that adds another decade to the lift. See /articles/rotary-lift-arm/ for single-arm details, or browse store.autoliftserv.com to see the arm and hardware inventory.
Arm restraint gear teeth: the failure point nobody sees
The gear teeth inside the arm restraint housing are the part that fails silently. They are under a spring-loaded pawl, and every time you swing an arm to a new position, those teeth take a click and a load. Over enough cycles, they round off. When they round off, the arm no longer holds position under a load shift — and load shifts are exactly what happens when a tech pushes on a wheel or drops a transmission into place.
Because the gear is hidden inside the housing, most shops do not inspect it until an arm slips. Our recommendation is: any time a restraint feels sloppy or the click is softer than you remember, pull the housing cap and look. New gears are cheap. Rotator cuffs are not. We stock the gears for every Rotary two-post family we sell, and they ship the same day out of Ames.
Ordering rotary lift arms for older, no-longer-current models
We get calls every week for rotary lift arms for lifts that Rotary no longer catalogs. Old SPO7, SPO9-Nxx, and legacy inground models are still running in shops across Iowa — Waterloo, Dubuque, Sioux City, Council Bluffs — and their owners want to keep them running. In most cases we can match the arm pattern to a current-production equivalent or source a specialty arm through our secondary channels.
Every arm we ship carries the correct capacity rating for the lift it is going onto. If your old lift’s arm design has been superseded because of a load-rating change, we will tell you and steer you toward the correct current-spec replacement. Safety trumps drop-in convenience every time. Send us the model and serial; if we cannot match it, we will tell you honestly and help you plan a replacement strategy for the lift itself.
Installing rotary lift arms without pulling the lift out
Full arm-set replacement does not require pulling the columns. The lift stays anchored, you lower it fully, lock it, and swap arms one at a time with the columns at rest. Total labor is usually four to six hours for a set of four on a common two-post — most of that is the restraint gear reassembly, not the arms themselves. It is a very manageable Saturday project for a shop with two techs.
Auto Lift Services sends installers across Iowa when a shop would rather have our team do the swap. We cover Des Moines, Cedar Rapids, Iowa City, Ames, Ankeny, Sioux City, Davenport, and Dubuque directly, and we regional-route to most of the surrounding states. Call 800-674-9302, email founder@autoliftserv.com, or start with the parts lookup online. Also see /articles/two-post-lift-safety-inspection/ before you order.
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