Graco 166057 Piston Seal

The Graco 166057 Piston Seal ensures tight sealing within the pump’s piston assembly, maintaining pressure and preventing internal leaks.

OEM replacement for electric airless pump lowers
Restores spray consistency and pressure
Durable and easy to install
Ideal for maintenance or pump rebuilds

$51.64

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Description

Overview & Key Details

Compatible Machines

Used in select Graco electric airless sprayer pump lowers. Confirm by checking your unit’s parts manual and pump lower code.

Graco 390 PC / 390 ST
Graco 395 PC / Ultra 395
Graco 490 PC Pro
Graco 495 PC Pro
Graco 595 PC Pro

Graco 166057 Piston Seal is an OEM seal for the piston area of the fluid section. It maintains pressure, prevents internal bypass, and supports consistent spray performance. Replace when experiencing pressure loss, inconsistent output, or internal leakage during pump operation.

Key Features

OEM fit for the piston location in compatible pump lowers
Helps restore prime, pressure stability, and atomization quality
Designed to reduce internal leakage/bypass for steady flow
Ideal for preventive maintenance during pump rebuilds

Technical Details

Part Number	166057
Part Type	Piston seal (fluid section)
Application	Electric airless sprayer pump lowers (select models listed above)
Function	Seals around piston to contain high-pressure fluid and prevent bypass
Installation Tip	Lightly lubricate seal; inspect piston rod/cylinder for scoring before assembly
Authenticity	Genuine OEM replacement part

When to Replace

Loss of pressure or difficult priming
Inconsistent spray pattern or output
Visible internal leakage during service

Frequently Asked Questions

Check your sprayer’s model, serial range, and the pump lower code in the official parts manual. The parts diagram should list 166057 at the piston seal position. If unsure, share the pump code with your distributor for verification.

Inspect the piston rod and cylinder wall for wear or scoring. Replace damaged components to avoid premature seal failure. Clean the groove, remove debris, and lubricate the new seal before installation.

Non-OEM seals may differ in material and profile, affecting pressure retention and lifespan. For best performance and fit, use the genuine part number listed in your machine’s parts breakdown.