Messy driveway? Oil leaking from your pressure washer pump? It’s probably the oil seal.
This is a small part with a big job: keeping oil in and water out. When it fails things get messy fast.
The good news? You can replace it yourself. You just need the right tools and a guide that doesn’t sound like a tech manual.
Let’s fix that seal. Step by step.
Before you tear anything apart make sure the oil seal is actually the issue.
Check for:
Oil leaking from the back side of the pump
Oily residue on the ground after use
Water in your pump oil (milky oil = water contamination)
If you’re seeing any of the above it’s definitely oil seal time.
Before you get started gather a few basic tools:
A socket set or wrenches
A flat-head screwdriver
Replacement oil seals
Clean rags
Pump oil
Optional but helpful: a seal puller or small pick tool and a plastic mallet.
1. Turn Off and Disconnect Everything
Unplug the unit. Turn off the fuel (if gas-powered). Disconnect water supply and spray gun. Safety first.
2. Drain the Oil
Remove the oil drain bolt (usually at the base of the pump) and drain the oil into a container. Let it drip completely.
3. Remove the Pump from the Engine
Most pressure washer pumps are bolted to the engine or motor. Remove the mounting bolts and gently slide the pump off the shaft.
Be careful not to force anything. If it’s stuck just gently wiggle it loose.
4. Access the Oil Seal
Remove the pump’s rear housing or crankcase cover. Inside you’ll see the pistons, bearings and the oil seals tucked behind the ceramic plungers.
5. Remove the Old Seal
Use a pick or seal puller to carefully pry out the worn oil seal. Be gentle. You don’t want to scratch the pump body.
6. Install the New Seal
Coat the new seal lightly with pump oil. Press it into place, lip side facing inward. Use a socket or dowel to press evenly. Make sure it sits flush.
7. Reassemble the Pump
Put everything back together in reverse order. Reattach the crankcase cover. Re-mount the pump to the engine. Tighten bolts snug (but don’t overdo it).
8. Refill with Fresh Pump Oil
Top it off with non-detergent pump oil to the fill line. Don’t use motor oil. It foams and causes issues.
9. Test It
Run the pressure washer for a minute. Look for leaks. If everything stays dry and smooth then you nailed it.
Always replace seals in sets if you’re doing multiple cylinders.
Clean as you go. Dirt in the crankcase is bad news.
Check your manual for torque specs or special seal orientation.
Inspect O-rings and gaskets while you’re in there. If they’re worn then replace them too.
Replacing an oil seal sounds intimidating but it’s totally doable. With a little time and the right parts your pressure washer will be back in business. Leak-free and blasting grime like it’s brand new.
Need parts? Looking for high-performance bearings or seals for heavy-duty applications? Check out NSAR bearings for the best of the best.
A bad oil seal can shut your whole operation down. But with the right tools you can fix it and get back to spraying in no time.
Don’t let a small leak become a big problem. Replace the seal and keep things flowing like usual.
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