Genie S45 Boom Cylinder Rebuild
If your Genie S45 is drooping at the boom, weeping oil down the tube, or won’t hold a lift-and-hold test anymore, you’re probably looking at a Genie S45 boom cylinder rebuild. We’ve done enough of these at the bench to know exactly what’s usually going on inside that tube before we even pull it off the machine — and we can tell you straight, most of the time it’s scoring on the barrel wall or a chewed-up piston seal, not a cracked casting.
We’re a family-run hydraulic shop at 210 Freel Dr in Ames, and a Genie S45 boom cylinder rebuild is one of the jobs we get called on regularly from rental yards and contractors running these lifts hard through Iowa summers and winters both. Heat cycling, dirty fluid, and a lift that sits outside more than it sits in a heated shop all add up to worn bores and shot seals faster than folks expect.
How we handle a Genie S45 boom cylinder rebuild
Every Genie S45 boom cylinder rebuild we do follows the same basic order, because skipping steps is how a cylinder comes back to us in three months instead of three years:
- Remove the cylinder from the boom and cap the ports so nothing walks into the hydraulic lines
- Tear it down completely — rod, piston, gland, and barrel inspected separately
- Check the bore for scoring, pitting, or out-of-round wear that a seal kit alone won’t fix
- Install new head seals, piston seals, U-seals, and wiper seals sized to the actual bore, not a guess off a parts catalog
- Reassemble, reinstall on the boom, and bleed the system so there’s no air pocket sneaking into the lift or lower cycle
On a lot of these units we’re pulling seal stock like a 3-inch head seal, a 3-inch piston seal, U-seals sized around 1-1/8 by 1-3/8, and a wiper seal to match the rod — but every Genie S45 boom cylinder rebuild gets measured on our end before we order, because a seal kit that’s off by even a few thousandths won’t seal and you’ll be right back here.
Common symptoms that mean you need a Genie S45 boom cylinder rebuild
Most calls we get start with one of a handful of complaints, and they almost always point back to the same handful of failures inside the cylinder:
- Boom drifts down on its own — usually a worn piston seal letting oil bypass internally
- Oil weeping around the rod — typically the wiper seal or rod seal has hardened and cracked
- Chatter or jerky movement raising the boom — often air in the system from a slow leak, or scoring inside the bore
- Visible scratches or a rough feel when the rod extends — this is bore scoring, and it means a straight seal swap won’t hold
That last one matters. A Genie S45 boom cylinder rebuild that only replaces seals on a scored barrel is a temporary fix at best — the new seals will chew up fast against damaged metal, and you’ll be calling us again in a few months. We tell customers this upfront rather than sell a quick patch that doesn’t last.
How much does a Genie S45 boom cylinder rebuild cost
Pricing on a Genie S45 boom cylinder rebuild depends mostly on what we find once it’s apart, but here’s the range we typically see:
- Seal kit rebuild with no bore damage: usually falls in the $600–$900 range including removal, rebuild, and reinstall with bleed-out
- If scoring is bad enough that the rebuild won’t hold and a new cylinder is required, add roughly $300 to $800 depending on whether it’s the smaller or larger cylinder on the boom
- Shop pickup or mobile service within 30–40 miles of Ames typically adds a mileage charge, usually $40–$75 round trip, less if it’s bundled with another job on site
One thing we tell every customer honestly: it’s really common for the other boom cylinder to blow out shortly after we rebuild the first one. If it’s been sitting worn that long, the second cylinder is usually not far behind. We’d rather tell you that now than have you surprised by a second call three weeks later. For a broader breakdown of what drives cost up or down across different cylinder types, our hydraulic cylinder rebuild cost guide walks through the variables in more detail.
If you’re not sure whether your machine needs a full Genie S45 boom cylinder rebuild or just a hose or fitting fix, bring it in and we’ll pressure test it before quoting anything. We do this same style of teardown-and-rebuild work on excavator cylinders too — see our excavator cylinder rebuild page for that side of the shop — and if you’re outside Ames proper we cover a good chunk of central Iowa, detailed on our Iowa cylinder rebuild service area page.
A Genie S45 boom cylinder rebuild isn’t a job to put off once you see drift or weeping — the longer it runs worn, the more it scores the bore and the more likely you end up buying a replacement cylinder instead of a rebuild. Give us a call at 515-292-2599 and we’ll get you scheduled, whether that’s dropping it at our shop on Freel Dr or sending a tech out to your site.
Frequently Asked Questions
How long does a Genie S45 boom cylinder rebuild take?
Most Genie S45 boom cylinder rebuild jobs take one to two days once the cylinder is off the machine, depending on whether we need to order a seal kit or have it in stock. Removal and reinstall on site can add a half day.
Can you rebuild the cylinder without removing it from the boom?
No — a proper Genie S45 boom cylinder rebuild requires pulling the cylinder off so we can fully inspect the bore, rod, and gland. Trying to reseal it in place risks missing scoring that will cause an early failure.
Will a seal kit fix a scored cylinder bore?
Not reliably. If the bore is scored or pitted, new seals will wear out fast against the damaged metal. In those cases a Genie S45 boom cylinder rebuild may need a new cylinder instead, usually adding $300 to $800 to the job.
Do you come to our site for a Genie S45 boom cylinder rebuild or does it need to come to your shop?
Both. We can remove and rebuild it at our shop on Freel Dr, or send a technician to your location within our mileage radius. Either way we bleed the system fully before calling the job done.
Why did the other boom cylinder fail right after you rebuilt this one?
It’s common — if one cylinder wore out from age, dirty fluid, or heat cycling, the matching cylinder is usually close behind. We flag this possibility upfront so it’s not a surprise if you’re back in a few months.
Written by Josiah Ragsdale, Ames Hydraulics