A rural farm shop north of Cedar Falls called us last winter because their rolling jack kept letting a wheel drop mid-rotation, and after twenty minutes on the phone it was clear the RJ 15 they’d bought secondhand had a safety-cam that wasn’t engaging at all. That’s the kind of failure that doesn’t show up until you’re under a truck with a torque wrench, and it’s exactly why we built this checklist. If you’re a farm shop owner in the Cedar Falls area doing your own tire rotation and wheel work on pickups, skid loaders, or grain trucks, here’s what to verify before you hand over money for an RJ 15, used or new.
Look up safety-cam kits, arm restraint hardware, and hydraulic seals before you buy — knowing parts are available changes the used-equipment math.
Item One: Verify the Safety-Cam Actually Engages
The safety-cam on an RJ 15 is the mechanical backup that holds the platform at height even if hydraulic pressure bleeds off, and it’s the single most important thing to test before you buy. Raise the jack, release hydraulic pressure fully, and confirm the platform holds its position without drifting down even slightly. If it settles even an inch, the cam isn’t catching correctly and you’re looking at either a worn cam profile or a bent engagement arm — both are repairable, but both are also leverage in your negotiation on a used unit.
We see this failure most often on farm shop purchases because rolling jacks in ag environments get exposed to grit, chaff, and moisture that a clean dealership bay never sees. Dirt in the cam mechanism prevents full engagement long before the metal itself wears out, so don’t assume a sluggish cam means the unit is junk — sometimes it just needs a thorough cleaning and fresh grease. Either way, test it standing clear of the platform, never with a hand or foot underneath, because that’s precisely the scenario this safety feature exists to protect against.
Item Two: Inspect Arm Restraint Hardware for Wear
Arm restraints on the RJ 15 keep the lifting arms from swinging or walking out from under the vehicle during tire rotation, and on a farm shop’s mixed fleet of pickups, skid loaders, and grain trucks, those arms take a beating from uneven weight distribution. Check every restraint pin and locking collar for elongation — a pin hole that’s gone oval instead of round means the restraint has been absorbing side-loading it wasn’t designed for, likely from lifting equipment at odd angles or on uneven shop floors.
Also pull each arm through its full range of motion and listen for grinding or feel for binding, which usually means the restraint bushing has worn thin and needs replacement before the arm itself takes damage. This matters more on a farm shop than a typical automotive bay because the vehicle mix is so varied — a grain truck’s dual rear wheels put different stress on the restraint system than a half-ton pickup, and the RJ 15 needs to handle both without the arms shifting mid-lift. Budget for restraint hardware replacement as a near-certain cost on any used unit that’s seen ag service.
Item Three: Confirm Load Rating Matches Your Heaviest Vehicle
Every RJ 15 has a rated capacity, and farm shops routinely underestimate what their heaviest vehicle actually weighs once you account for loaded beds, mounted equipment, or dual rear wheel setups. Before you buy, identify the single heaviest vehicle or wheel-end load you’ll ever put on the jack and confirm the unit’s rating clears that number with real margin — not a number that just barely covers it on paper.
Rolling jacks that are chronically overloaded show accelerated wear on the exact components we’ve already flagged — the safety-cam and the arm restraints — so a unit with a marginal load history is more likely to fail those first two checks even if it looks fine sitting still. If a seller can’t tell you the operating history of a used RJ 15, treat that uncertainty as a real cost and inspect the cam and restraints twice as carefully. A jack that’s spent its life on light-duty passenger vehicles is a very different purchase than one pulled from a heavy fleet shop, even if the model number on the tag is identical.
Item Four: Check Hydraulic Seal Condition and Fill Plug
A slow hydraulic leak on an RJ 15 often shows up first as a damp fill plug or a faint oil film around the base rather than an obvious puddle, so run your hand around the reservoir and cylinder base during inspection. The plastic fill plug on these units is a common wear point and one we stock regularly because it cracks with age and temperature swings — a farm shop that stores equipment in an unheated building over an Iowa winter will see this fail faster than a heated bay would.
Test the foot pump through a full raise-and-hold cycle and watch for pressure bleeding off faster than the safety-cam should allow it to drop — that gap tells you whether you’re dealing with a simple seal replacement or something more serious in the cylinder itself. Seals and fill plugs are inexpensive and easy for us to source, so don’t let a leak alone kill a deal on an otherwise sound unit; just factor the repair into your offer and confirm parts availability before you commit.
Item Five: Test Rolling Resistance on Your Actual Shop Floor
An RJ 15 needs to roll smoothly on the runway or rail system it’ll actually live on, and farm shop floors — especially older concrete with expansion joints or minor heaving — can bind casters that rolled fine in a dealer’s showroom. Walk the unit through its full range on your own floor before finalizing a purchase, not just on the seller’s floor, because caster performance is floor-dependent in ways that aren’t obvious until you try it.
If the jack drags or requires excessive force to reposition, check caster wheels for flat spots or debris packed in the bearing before assuming the floor itself is the problem. Farm shops with dirt or gravel tracked in from equipment yards see caster contamination far more than a typical automotive service bay, and a five-minute cleaning often solves what looks like a structural issue. This is a cheap, fast test that tells you a lot about how the previous owner maintained the unit overall.
Item Six: Review Documented Maintenance History If Available
Ask directly whether the seller has any maintenance records, even informal ones, because a rolling jack that’s been greased on schedule and inspected regularly is a fundamentally different purchase than one that’s been run hard with no attention. Farm shop owners buying used equipment often skip this question because ag equipment culture assumes machines get used until they break — but an RJ 15 with documented care is worth paying more for even if the asking price seems high at first glance.
If there’s no history available, treat the unit as if it’s had zero maintenance and price your offer accordingly, then plan to do a full teardown inspection of the safety-cam, restraints, and hydraulic system before it goes into regular service on your farm. We’ve helped several Cedar Falls-area shop owners do exactly this kind of inspection on a unit before first use, and it’s cheap insurance compared to finding a problem while a truck is already in the air.
Item Seven: Confirm Parts Support Before You Sign
The last item on this checklist is the one people skip most often — confirming that replacement parts for the RJ 15 are actually available before you finalize the purchase. Farm shops are often located well outside a dealership’s typical service radius, and waiting a week on freight for a fill plug or restraint pin means a truck sits idle during a busy season. We stock the common wear parts for these rolling jacks specifically because we work with rural Iowa shops that can’t afford that kind of downtime.
Before you buy, ask the seller or manufacturer directly whether cams, restraints, seals, and fill plugs are still in production or readily stocked, and don’t assume an older unit is automatically a parts problem — many the lift components have stayed consistent across model years specifically because they’re standard wear items. If you’re weighing a used unit against something new, factor parts availability into that decision the same way you’d factor in purchase price, because a jack you can’t repair quickly isn’t actually saving your farm shop money in the long run.
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