Simpson ALH4240 Pressure Washer Parts & Accessories

Genuine Simpson® OEM parts, compatible replacements, and accessories for the 4200 PSI 4.0 GPM Honda Cold Water Direct Drive Gas Pressure Washer by SIMPSON (49-State). Everything on this page is confirmed to fit the Simpson ALH4240.

The machine

Need to replace the whole unit? Shop the Simpson ALH4240 pressure washer here →

Owner’s manual & parts diagram

• 📘 Owner’s manual (PDF): Download →
• 📘 Owner’s manual (PDF): Download →
• 📘 Owner’s manual (PDF): Download →
• 📄 Full parts diagram (PDF): Download the full exploded 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 stock for the ALH4240

• 7111659 — WHEEL MOUNTING KIT
• 7103292 — KIT, FOOT SVC ASY
• 7107583 — CAT PUMP
• 7107941 — KNOB-BOLT ASSEMBLY
• 7102207 — KIT, SVC ASSY SOAP HOSE W/PLASTIC FILTER

Compatible replacement categories

For hoses, wands, guns, and pumps we also stock third-party replacements that fit the ALH4240:

• 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 ALH4240 or need help identifying the right part? Call 412-744-4004.