If you've noticed your sprinkler system isn't quite hitting the marks it used to, or there's a persistent puddle forming under your pump, it might be time to look into a goulds gt15 pump rebuild kit. These Irri-Gator pumps are absolute workhorses in the residential world, but like any piece of machinery that deals with water and pressure day in and day out, the seals eventually give up the ghost. Instead of dropping several hundred dollars on a brand-new unit, a rebuild kit is usually all you need to get things back to peak performance.
It's one of those projects that looks a bit intimidating from the outside, but once you get the pump on a workbench, it's actually pretty straightforward. Most people find that their pump motor is still spinning perfectly fine, but the internal components—the parts that actually move the water and keep it from leaking—are just worn down. That's where the kit comes in to save the day (and your wallet).
Is It Time to Rebuild Your Pump?
You'll usually get some pretty clear warnings before a GT15 completely quits on you. One of the most common signs is a slow drip coming from the bottom of the pump housing where the motor meets the wet end. That's a classic symptom of a failing mechanical seal. If you ignore it, that water can eventually find its way into the motor bearings, and then you're looking at a much more expensive repair.
Another red flag is a loss of pressure. If your irrigation heads are barely popping up or the flow feels weak, your internal O-rings or the diffuser might be compromised. Sometimes, the pump might even struggle to prime because it's sucking in air through a dried-out gasket. If you're hearing a high-pitched squealing sound, that's usually the bearings, but the leaking seal often causes that damage in the first place. Catching it early with a goulds gt15 pump rebuild kit can prevent the motor from burning out.
What You'll Find in the Kit
When you finally get your hands on a goulds gt15 pump rebuild kit, don't expect a massive box of hundreds of parts. These kits are designed to be efficient. Usually, the "meat" of the kit is the mechanical seal. This is a two-piece component that's responsible for keeping water inside the pump casing and away from the electrical motor. It's the most critical part of the whole operation.
Beyond the mechanical seal, you'll typically find a variety of O-rings. There's usually a large one for the casing (the "big squeeze" that prevents leaks between the two halves of the pump) and smaller ones for the diffuser or the pressure switch connection. Some higher-end kits might include a new impeller or a wear ring, but for a standard maintenance rebuild, the seals and gaskets are the stars of the show. It's always a good idea to double-check the contents before you start tearing things apart, just so you aren't left stranded with a disassembled pump on a Sunday afternoon.
Getting Down to Business: The Teardown
Before you touch a single bolt, please, for the love of everything, turn off the power at the breaker. Working with water and electricity is never a good mix. Once it's powered down and the pipes are disconnected, you can move the pump to a flat surface where you won't lose any screws.
Opening the Casing
You'll start by removing the casing bolts. These can be a bit stubborn if they've been sitting in the elements for five years, so a little penetrating oil doesn't hurt. Once those are out, the pump "splits" open. This is where you'll see the impeller and the diffuser. Take a second to look at how everything is layered. I always recommend taking a quick photo with your phone at each step. It's way easier than trying to remember which way that weird-looking plastic ring was facing an hour later.
Removing the Impeller
To get to the mechanical seal, you have to take the impeller off. On a GT15, this usually involves holding the motor shaft steady (there's often a slot on the back of the motor under a small cap) while you unscrew the impeller. It's a standard thread, so "lefty-loosey" applies here. Be careful not to manhandle it; if you crack the impeller, you'll be ordering more parts. Once that's off, the old seal will be visible.
Installing the New Seals Correctly
This is the part where most people get a little nervous, but it's actually the most important step in using your goulds gt15 pump rebuild kit. The mechanical seal has two halves: a stationary ceramic seat and a spring-loaded rotating member.
One golden rule: Do not touch the faces of the seal with your bare fingers. The oils from your skin can actually cause the seal to fail prematurely once it gets hot. Use a clean cloth or the plastic wrapper it came in to push the pieces into place.
You'll want to press the ceramic seat into the bracket of the pump. A little bit of soapy water (just a drop!) can help it slide in without tearing the rubber boot. Then, the other half of the seal slides onto the shaft. Once those are in, you can spin the impeller back on. The pressure from the impeller being tightened down is what actually creates the seal between those two faces.
Replacing the O-Rings
While you have everything open, swap out every O-ring included in your goulds gt15 pump rebuild kit. Even if the old ones look "okay," they've likely flattened out or become brittle over time. A little bit of silicone-based lubricant (not petroleum jelly!) on the new O-rings will help them seat correctly and prevent them from getting pinched when you bolt the casing back together.
Reassembly and Testing
Putting it back together is basically just the reverse of taking it apart. Line up the casing, get those bolts started by hand so you don't cross-thread them, and tighten them in a "star" pattern. This ensures the pressure is even across the whole gasket, which is key to a leak-free seal.
Once everything is tight and the pipes are hooked back up, you've got to prime the pump. Don't just flip the switch and hope for the best. Fill the casing with water through the prime plug until it's overflowing, then seal it up. When you turn it on, it might take a minute to clear the air out of the lines, but you should see a much stronger, steadier flow than before.
Why Rebuilding is Better than Replacing
I get asked a lot if it's really worth the effort to use a goulds gt15 pump rebuild kit instead of just buying a new GT15. To be honest, unless your motor is completely shot or the cast iron housing is cracked, rebuilding is almost always the better move.
First off, it's way cheaper. A kit costs a fraction of a new pump. Second, you don't have to mess with the plumbing as much. If you replace the whole unit, you might find that the new one sits slightly differently, requiring you to re-cut and re-glue your PVC pipes. By rebuilding, you keep the same footprint. Plus, there's a certain level of satisfaction that comes from fixing something yourself. You'll know exactly how that pump works, which makes future maintenance a total breeze.
Keeping Your Pump Healthy Long-Term
After you've successfully used your goulds gt15 pump rebuild kit, you probably want to make sure you don't have to do it again for a long time. The biggest killer of these seals is running the pump dry. If your well or water source runs low and the pump keeps spinning without water to cool the seal, it'll heat up and crack in seconds.
If you live in a cold climate, winterizing is also huge. Water expands when it freezes, and it will absolutely wreck a GT15 casing or blow out your new seals if it's left inside. Drain the pump completely before the first frost. A little bit of preventative care goes a long way in making sure your rebuild lasts for years to come.
At the end of the day, these Goulds pumps are built to be serviced. They aren't "throwaway" appliances. Using a goulds gt15 pump rebuild kit is just part of being a responsible homeowner and keeping your lawn green without breaking the bank. It might take you an hour or two on a Saturday, but the result is a pump that runs like it just came off the factory floor.