AR880520 Oil Seal 20x28x6mm AR RK/RKA Pumps - 2817

AR880520 Oil Seal at a Glance

The AR880520 is a genuine Annovi Reverberi (AR North America) replacement oil seal engineered for high-pressure pressure washer pumps. Its primary job is straightforward: keep pump oil contained inside the crankcase while blocking water, dirt, and detergents from entering - ensuring your pump stays lubricated, cool, and operating at full capacity. The AR880520 oil seal is used in various AR high-pressure commercial and industrial water pumps, with common fitment in the RK and RKA series pump lines used across residential and commercial pressure washers. 

Reliable Sealing Performance

Engineered to keep your AR high-pressure pump running leak-free under demanding conditions, protecting internal components and sustaining consistent operating pressure.

The AR880520 delivers a focused outcome: leak prevention that translates directly into longer pump life and uninterrupted cleaning performance. No complicated features to parse - just a precision-fit oil seal that does its job so you can focus on yours.

Why You'll Appreciate the AR880520 Oil Seal

A component as small as an oil seal has an outsized impact on pump reliability. When this part fails, everything downstream suffers - from lubrication to pressure consistency to the cost of emergency repair. Here's why the AR880520 stands out as the right product for the job:

• Leak-free pump performance – A properly installed AR880520 stops oil seepage around the crankshaft area, keeping lubricant where it belongs and protecting precision-machined internal parts from running dry.

• Protects against premature pump failure – The AR880520 is an OEM replacement oil seal designed to retain crankcase oil, preventing the kind of oil loss that leads to overheating, scoring, and expensive internal damage.

• Consistent high pressure for cleaning – Maintaining correct oil volume supports steady working pressure whether you're tackling driveway concrete, building siding, or fleet wash-downs. When quality matters in seal integrity, every PSI counts.

• Reduced maintenance interruptions – Fewer unexpected shutdowns for diagnosing leaks or topping up oil means more productive hours on the job for contractors and facilities teams alike.

• Suitable for both residential and professional use – From homeowners running weekend clean-up sessions to professional customers operating AR-equipped washers daily, dependable sealing performance keeps everyone's equipment in service.

• Peace of mind with an OEM-spec part – Using the correct AR North America part helps maintain pump integrity and keeps warranty considerations intact. Generic substitutes often compromise the fit and material quality that AR pumps demand.

• Constructed for demanding environments – AR880520 acts as a dynamic seal inside the pump housing, constructed to handle the vibration, heat cycles, and pressure pulses that high-pressure pump duty imposes on every component.

What Makes the AR880520 Oil Seal Different

Low-quality or incorrectly sized oil seals are one of the most common causes of preventable pump failure in pressure washer equipment. Generic seals frequently suffer from premature hardening, lip blowouts under high pressure surges, and poor dimensional fit that allows oil to weep past the contact surface within weeks. These breakouts in seal integrity create cascading problems - from contaminated crankcase oil to seized bearings.

The AR880520 is built differently:

• Designed specifically for AR high-pressure pumps – The geometry and tolerances of this seal are matched to AR crankshafts and pump housings. AR880520 is listed as a specific component in RK and RKA series pump constructions, ensuring the lip angle, interference fit, and seating depth align precisely with the machined bore. That precision is something generic parts simply cannot guarantee.

• Formulated for high-pressure, high-heat environments – The elastomer compound and internal reinforcement are selected to withstand continuous vibration, pressure pulses, and elevated operating temperatures. AR880520 is typically used in AR triplex plunger and piston pump assemblies, where conditions push seals to their limits.

• Stable sealing over time – Resistance to swelling, cracking, and deformation in common pump oils means the AR880520 maintains its sealing contact long after generic alternatives have begun to degrade. AR880520 serves to keep crankcase oil contained and prevents contaminants from entering throughout its service life.

• Backed by AR North America's pump expertise – Annovi Reverberi brings decades of pump manufacturing experience to every component they produce. When you buy parts from the same company that engineered the pump, you're getting the benefit of field-tested material selection and design validation that aftermarket suppliers rarely replicate.

How the AR880520 Oil Seal Works in Your Pump

The AR880520 sits around a rotating shaft in the pump crankcase, forming a continuous barrier between the lubricating oil inside and the external environment. AR880520 prevents contamination within high-pressure plunger and piston pumps by working as a dynamic interface between moving and stationary surfaces. Here's what happens in practice:

Step 1 – Seating in the pump housing. The outer diameter of AR880520, approximately 2.7 cm, presses into the machined bore of the pump crankcase. This static fit creates a tight peripheral seal against the housing wall, preventing oil from bypassing between the seal body and the bore.

Step 2 – Dynamic sealing on the shaft. The inner diameter, approximately 1.7 cm, forms a snug, lubricated contact around the spinning crankshaft. As the shaft rotates at operating speeds - which in RK-series pumps can reach 1,450 to 1,750 RPM - the seal lip maintains constant contact under light spring tension, holding oil in even as pressure fluctuates during pump cycles.

Step 3 – Continuous protection under pressure. During operation, the seal maintains oil on the crankcase side while keeping water, cleaning chemicals, and grit on the outside. This dual-barrier function supports smooth pump performance by ensuring lubrication stays clean and at the correct level, cycle after cycle.

Product Details and Specifications

These are the practical specs to check before you order or install the AR880520:

• Brand / Manufacturer – Annovi Reverberi (AR North America), a specialist in high-pressure plunger and diaphragm pumps for pressure washer and industrial water applications.

• Part Number – AR880520, an oil seal for high-pressure pump crankcase applications.

• Approximate Dimensions – Outer diameter: ~2.7 cm; inner diameter: ~1.7 cm; width: 6 mm. The compact profile is suited to AR crankcase bores in applicable pump models.

• Material – High-quality engineered elastomer (oil-resistant rubber) with internal reinforcement, suitable for high-pressure, oil-lubricated environments with exposure to heat and vibration.

• Operating Environment – Intended for use with pump oil in high-pressure washer pumps encountering vibration, heat, pressure pulses, and intermittent duty cycles.

• Compatibility Overview – AR880520 is listed in selected AR high-pressure pump series, including RK and RKA configurations. Three AR880520 seals are commonly used per pump assembly in applicable configurations. Always verify against your pump manual, data plate, or AR parts diagram before ordering.

• Included in the Package – A single AR880520 oil seal per item. Other gaskets, O-rings, ring seals, or packings are purchased separately as needed.

• Warranty / Support – AR North America classifies seals as wearable items. Warranty coverage is handled through authorized service dealers and distributors, like Barens, subject to correct installation and operating conditions.

Compatibility and Fit: Is AR880520 Right for Your Pump?

Oil seals are model-specific components, and confirming compatibility before you replace the existing seal avoids leaks, rework, and the frustration of ordering the wrong product. Even a small dimensional error can lead to a seal that won't seat properly or that gets blown out under operating pressure.

To verify fit, start by locating your pump model number. This is typically found on a nameplate or tag affixed to the pump body, or etched directly into the crankcase housing. Cross-check AR880520 against the exploded parts diagram or service manual for your specific AR pump model - in RK 1750 RPM breakdowns, for example, the 880520 appears at position 16 as "Oil Seal."

While the approximate dimensions are ~2.7 cm OD and ~1.7 cm ID, do not rely on rough measurements alone when selecting seals. Measure the existing seal's inner diameter, outer diameter, and width, and compare those against the spec for AR880520. Typical application scenarios include residential pressure washers driven by gas engines, light commercial units, and compact electric pressure washers using AR pumps.

If your pump uses a different shaft diameter or housing bore size, another AR seal part number may be required. When in doubt, consult AR North America or an authorized service center. The cost of a quick verification call is far less than the cost of pump damage from the wrong seal.

Who Benefits Most from the AR880520 Oil Seal

This seal is aimed at anyone responsible for keeping AR pressure washers and high-pressure pumps in reliable service - whether that's a single machine or an entire fleet.

• Professional pressure-washing contractors – Need fast, reliable fixes for oil leaks to keep multiple washers productive on jobsites. Downtime costs money, and having the right AR parts on hand prevents delays.

• Facilities and maintenance teams – Use AR-equipped washers for cleaning equipment, loading docks, and building exteriors, and prioritize minimizing equipment downtime over chasing low-cost generic alternatives.

• Small engine and equipment repair shops – Regularly service AR high-pressure pumps and prefer OEM-spec seals for predictable results and fewer customer comebacks. Seal repair kits allow direct installation without special skills, but professional shops ensure correct orientation and shaft inspection every time.

• DIY homeowners and hobbyists – Comfortable with basic mechanical repairs on their own pressure washer and want an exact-fit oil seal to restore performance without guesswork.

If your AR pump shows signs of oil seepage near the crankcase or shaft, the AR880520 may be the targeted fix - assuming compatibility with your pump model is confirmed.

Basic Installation Overview for the AR880520 Oil Seal

Safety first: Before beginning any repair, disconnect the spark plug wire or power supply, relieve all system pressure, and review your pump's service guide. If you're not confident working with pump internals, share the job with a qualified technician or take the unit to an authorized service center.

This guide is a high-level overview - not a substitute for your pump's full service documentation.

• 1. Prepare the pressure washer and workspace – Turn off the engine or motor, disconnect the power source, relieve system pressure, and drain pump oil if recommended. Clean the exterior of the pump to prevent dirt from entering during disassembly.

• 2. Access the pump crankcase – Remove covers and unbolt the pump from the engine or frame if required. Open the crankcase or rear housing per AR's maintenance instructions for your model.

• 3. Remove the worn oil seal – Carefully pry out the old seal from its bore without scratching the shaft or housing. Note the orientation of the old seal - which side faces the oil matters for correct reinstallation.

• 4. Inspect and clean mating surfaces – Check the shaft for grooves, rust, or scoring. Wipe away old oil and debris from the bore and shaft area. If the shaft is damaged, replacing the seal alone may not resolve leaking.

• 5. Install the new AR880520 seal – It is essential to install the AR880520 oil seal correctly to prevent leaks. Powdered sealing lip lubrication before installation prevents future seal failure - lightly coat the inner lip with clean pump oil, align the seal squarely over the shaft, and press it evenly into the housing bore to the correct depth, maintaining proper orientation.

• 6. Reassemble and test – Refit the crankcase cover, refill with the recommended pump oil, reinstall the pump on the machine, and run at low load first to confirm there are no fresh leaks around the seal.

Torque values, specific disassembly sequences, and seal-driving tool recommendations should be taken directly from AR North America's service documentation for your exact pump model.

Maintenance Tips to Extend Seal Life

Proper maintenance of the entire pump system helps the AR880520 seal deliver maximum service life. A few focused habits make a significant difference:

• Use the correct pump oil – Follow AR's recommendation for oil type and viscosity. Incompatible fluids can cause the elastomer to swell, harden, or lose elasticity, shortening seal life dramatically.

• Avoid extended dry running – Running the pump without water flow or with blocked discharge can overheat internal components, bake lubricant onto sealing surfaces, and stress seals beyond their design limits. Preventive maintenance for seals includes regular oil changes and ensuring proper crankcase ventilation.

• Protect against contamination – Keep the pump body and shaft area clean to reduce the chance of grit, sand, or chemical residue attacking the seal lip during operation or storage.

• Monitor for early signs of leakage – After heavy use, check beneath the pump and around the crankcase for oil spots. Catching a small leak early is far cheaper than dealing with a seized crankshaft or scored bore.

• Follow regular service intervals – Periodic oil changes and inspection of packings, seals, and O-ring components per AR's schedule keep the full system performing at its best. 

Frequently Asked Questions About the AR880520 Oil Seal

These are common questions from technicians, shop owners, and customers replacing AR pump seals.

Is the AR880520 oil seal easy to install? Experienced DIY users or technicians familiar with pump disassembly can typically install it with standard hand tools. Correct orientation and care during seating are essential - forcing the seal at an angle or damaging the lip during installation will compromise its performance immediately.

How do I know if my existing seal has failed? Look for oil dripping from the rear of the pump, an oil film accumulating on the frame or engine mount, or a noticeable drop in crankcase oil level over time. Any of these signs indicate that the seal may need replacement.

Can I use a generic seal with similar dimensions instead? While some generic seals might physically fit, using an AR-spec seal like the AR880520 helps ensure correct material compatibility and long-term performance at high pressure. 

Does AR880520 fit every AR North America pump? No. Compatibility depends on shaft and housing dimensions specific to each pump model. AR880520 is listed in RK and RKA series breakdowns, but users must confirm the part number against their pump's parts list before ordering. A video walkthrough of your specific pump model's breakdown can also help verify correct part selection.

How long should an AR oil seal typically last? Service life depends on operating hours, conditions, maintenance practices, and oil quality. With proper care - correct oil, no dry running, clean operating environment - seals are designed for extended service in typical pressure washer duty cycles. There is no universal hour rating; inspect at each scheduled oil change.

What should I check if I still see oil after replacement? Verify the seal's installation orientation, inspect the shaft surface for grooves or scoring, check crankcase gaskets and adjacent ring seals, and confirm that the leak is actually coming from the oil seal location rather than another component.

Ready to Restore Your AR Pump's Sealing Performance?

Replacing a worn seal with the AR North America AR880520 is one of the most cost-effective ways to restore leak-free operation and protect your high-pressure pump investment. A few dollars in parts and an hour of focused work can prevent hundreds of dollars in crankcase damage, ensuring your equipment stays productive instead of sitting on a bench.

Contact the team at Barens to confirm part compatibility using your pump model number and AR's official parts documentation. Gather your tools, review the service manual, and plan the replacement during scheduled maintenance rather than waiting for a major leak to force your hand. Proactive seal replacement is the kind of low-cost, high-impact maintenance that separates well-run equipment programs from reactive ones.

Your AR pump was built to deliver reliable high-pressure performance. The AR880520 oil seal helps it keep that promise.