Graco 166026 Piston Seal

Essential piston seal for Graco contractor pumps—restores pressure and stops bypass. Check your sprayer’s parts manual to confirm the part number before ordering.

Part No.: 166026 (166-026)
Fits: Ultra Max II 695, 795, 1095, 1595 (verify pump listing)
Function: Seals piston to cylinder in the fluid section
Replace when: Pressure drops, surging, or paint bypass occurs
Install tip: Clean surfaces, lightly lubricate, avoid twisting, test pressure after

Retail Price: $71.75

You save: $1.26 (1.76%)

Our Price: $70.49

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Description

Compatibility & Technical Overview

Compatible Machines

This piston seal fits the following Graco contractor-grade sprayers (verify by parts manual before ordering):

Ultra Max II 695
Ultra Max II 795
Ultra Max II 1095
Ultra Max II 1595
Other Graco sprayers using the same displacement pump where part 166026 is specified

What it is

The 166026 piston seal is used in the pump’s fluid section to seal the reciprocating piston against the cylinder, maintaining pressure and preventing bypass for consistent spray output.

Key Benefits

Restores pressure and smooth spray pattern when the original seal is worn
Built to OEM dimensions for reliable fit and performance
Durable elastomer design for professional-duty applications

Quick Specs

Part Number	166026 (166-026)
Component Type	Piston Seal (fluid section)
Application	Airless sprayer displacement pump seal
When to Replace	Pressure drop, paint bypass, pulsing, or uneven pattern

Fitment Tips

Confirm by checking your sprayer’s parts manual or pump exploded view for 166026
Inspect piston and cylinder surfaces; clean and lubricate per pump instructions before install
After assembly, test for proper pressure build and leaks

Frequently Asked Questions

Question	Answer
How do I confirm compatibility?	Match the part number in your sprayer’s parts list; if the pump diagram specifies 166026, this is the correct seal.
What symptoms indicate a worn piston seal?	Reduced pressure, visible bypass/leakage, surging output, and inconsistent fan pattern.
Do I need other parts when replacing the seal?	It’s good practice to inspect packings, backup rings, and piston surfaces; replace any worn items during service.
Any installation best practices?	Depressurize, clean components, lightly lubricate, seat the seal without twisting, and verify pressure after reassembly.