Hydraulic Motor Seal Replacement in Ames, Iowa
When a hydraulic motor starts weeping fluid out the shaft or loses power under load, nine times out of ten it comes down to worn seals inside the housing. We do hydraulic motor seal replacement on the bench almost every week for skid steers, excavators, mowers, and ag equipment that come through our shop at 210 Freel Dr. It’s not glamorous work, but it’s the kind of job that keeps a piece of equipment running instead of sitting in a field losing money.
Hydraulic motor seal replacement is a lot like the cylinder rebuild work we do all day — same shop, same seal suppliers, same basic idea. You’ve got a shaft seal keeping fluid inside the case, a case drain seal, and sometimes internal wear plates or gerotor seals depending on the motor style. We’ve pulled motors apart where the shaft seal was so far gone that oil was pumping straight out onto the frame, and others where scoring on the shaft itself meant the seal never had a chance no matter how new it was.
How We Do Hydraulic Motor Seal Replacement
Every hydraulic motor seal replacement job starts the same way — the motor comes off the machine and onto our bench so we can actually see what’s going on instead of guessing under a piece of equipment in a field. Here’s the general process:
- Remove the motor and cap off the hydraulic lines to keep dirt out of the system
- Tear the motor down and inspect the shaft, bearings, gerotor set, and housing bore for scoring or wear
- Measure the shaft and bore against OEM spec — if the shaft is scored, no new seal will hold for long
- Pull the correct seal kit — shaft seal, case seal, O-rings, and wipers sized to that specific motor
- Reassemble, torque to spec, and pressure test before it goes back on the machine
- Bleed the system and run it under load to check for leaks before you leave our lot
That scoring issue is worth mentioning again because it’s the thing that trips people up. We’ve had customers assume a seal kit alone will fix a leaking motor, and most of the time it does — but if the shaft is grooved from years of a bad seal grinding into it, a fresh seal kit will leak again within weeks. We’ll tell you straight if that’s what we’re looking at before we button it back up.
Signs You Need Hydraulic Motor Seal Replacement
Most folks bring a motor in after they’ve already noticed something’s off. Here’s what usually points to needing hydraulic motor seal replacement rather than a bigger internal failure:
- Oil weeping or dripping from the motor shaft area, especially when the machine sits overnight
- Loss of torque or the motor stalling under load it used to handle fine
- A whining or grinding noise that gets worse as the motor warms up
- Fluid showing up in the case drain line in amounts that keep climbing
- Visible fluid buildup around the motor mount or nearby hoses that wasn’t there before
If you catch it early, hydraulic motor seal replacement is usually a straightforward bench job. If you wait, that leaking seal lets dirt and moisture into the case, which chews up bearings and the gerotor set, and now you’re looking at a full motor rebuild or replacement instead of a seal kit. We see the same pattern with cylinders — a small leak ignored long enough turns into a much bigger repair, which is part of why we put together a cylinder rebuild cost guide for folks trying to figure out where their equipment stands.
How Much Does Hydraulic Motor Seal Replacement Cost
Pricing depends on the motor size, how many seals need replacing, and whether the shaft or bore is damaged underneath. Rough ranges we typically see:
- Small motor, shaft seal and O-rings only, no scoring: $150–$350 in parts and labor
- Mid-size motor with case seal, wipers, and full seal kit: $300–$600
- Larger excavator or skid steer drive motor with internal wear needing bore work: $600–$1,200+
- If scoring means the shaft or internal components need replacing beyond seals, expect an added $300–$800 on top depending on parts availability
We also charge mileage if we’re coming to you instead of you bringing the motor in — typically figured at 40 miles round trip for jobs within our normal service area, with a technician on site for removal, mileage, and pickup tasks. If you’re outside Ames proper, we still cover a good chunk of central Iowa; check our Iowa service area page for details, since the same trucks and techs handle both cylinder and motor work.
What We Check Before We Call It Done
A motor that’s had hydraulic motor seal replacement doesn’t leave our shop until it’s held pressure and run under load. We’ve had cases where a rebuilt cylinder holds fine but the neighboring cylinder on the same machine blows out shortly after — same logic applies to motors on multi-motor systems. If one motor was leaking because of contaminated fluid or a bad relief valve upstream, the other motor on that circuit may be close behind. We’ll flag that for you rather than let you find out the hard way.
If you’re dealing with an excavator swing motor or travel motor specifically, that’s a slightly different animal than a standard gerotor motor, and we handle those too — similar seal logic, bigger parts. Folks around Boone bring those in through our excavator cylinder rebuild service, and if the final drive itself is involved rather than just the motor, that’s a job for our final drive rebuild crew.
Whether it’s a mower deck motor leaking down overnight or a skid steer drive motor losing power halfway through a job, hydraulic motor seal replacement is bread-and-butter work for us. We keep common seal kits on hand and can usually turn a straightforward job around in a day or two once the motor is on our bench. Give us a call at 515-292-2599 and tell us what the machine is doing — we’ll walk you through what it probably needs before you even bring it in.
Frequently Asked Questions
How do I know if my hydraulic motor needs a seal replacement or a full rebuild?
If the shaft and bore check out clean under measurement and the only issue is fluid weeping past the seal, a seal kit is usually enough. If there’s scoring on the shaft or wear in the gerotor set, hydraulic motor seal replacement alone won’t hold and you’re looking at a fuller rebuild.
Can I do hydraulic motor seal replacement myself?
It’s possible with the right seal kit and shop manual, but a lot of failures come down to shaft scoring or bore wear that’s hard to catch without measuring tools. We’d rather you call 515-292-2599 first so we can tell you what to check before you tear into it.
How long does hydraulic motor seal replacement take?
Most motors we pull in for seal work turn around in a day or two once they’re on our bench, assuming the seal kit is in stock and there’s no internal damage. Larger drive motors or ones needing parts on order can take longer.
Why does my hydraulic motor keep leaking after a seal replacement?
Usually it’s shaft scoring, a damaged bore, or contaminated fluid that’s chewing through the new seal fast. We check all three before we send a motor back out, but if a previous repair skipped that step, the leak will come right back.
Do you offer mobile hydraulic motor seal replacement in Ames?
We can come out for removal and pickup on larger equipment, with mileage figured for the trip, but the actual teardown and hydraulic motor seal replacement happens on our bench at 210 Freel Dr where we’ve got the right tools and pressure test setup.
Written by Josiah Ragsdale, Ames Hydraulics