Simpson WB4200 Pressure Washer Parts & Accessories

Genuine Simpson® OEM parts, compatible replacements, and accessories for the Simpson WB4200 49-State 4200 PSI at 4.0 GPM HONDA® GX390 with AAA® Triplex Plunger Pump Cold Water Professional Belt Drive Gas Pressure Washer. Everything on this page is confirmed to fit the Simpson WB4200.

The machine

Need to replace the whole unit? Shop the Simpson WB4200 pressure washer here →

Owner’s manual & parts diagram

The three parts that fail first (most-requested)

1. Replacement pump — the most common wear item after 300-500 hours or freeze damage. Check the parts diagram for the exact model.
2. Replacement pressure hose — 3/8" wire-braid hose. Shop Simpson pressure washer hoses →
3. Replacement wand / lance — cracked, bent, or corroded wands are the #1 field-replaceable item after nozzles.

Genuine Simpson OEM parts

We can order most Simpson OEM parts for the WB4200 direct from the factory. Call 412-744-4004 with the part number from the full parts diagram (linked above) and we’ll get it to you.

Compatible replacement categories

For hoses, wands, guns, and pumps we also stock third-party replacements that fit the WB4200:

• Simpson-compatible pressure washer hoses
• Pressure washer guns, wands & extensions
• Pressure washer quick-connect nozzles & couplers
• Triplex plunger replacement pumps
• Full pressure washer pump catalog

Don’t see the part you need? Call us at 412-744-4004 — we can order most Simpson OEM parts direct from the factory.

Pittsburgh Spray Equipment has been the region’s pressure washer service specialist since 1947. Questions on your WB4200 or need help identifying the right part? Call 412-744-4004.