Graco 235703 Pump Repair Kit

The Graco 235703 Pump Repair Kit restores optimal pressure and performance in older ST and STS airless sprayers. Ideal for maintenance or rebuilding the pump’s fluid section.

OEM packing kit for Graco 390 ST / STS, 395 ST / STS, 450 ST, 455 ST, and 490 ST.
Includes leather and poly packings, O-rings, seals, and spacers.
Designed to stop leakage, improve priming, and extend pump life.

Retail Price: $92.5

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Description

Compatible Machines – Quick List

The Graco 235703 Pump Repair Kit (OEM packing kit) services the fluid section on select legacy contractor-grade sprayers. Verify your exact model and series before ordering.

Graco 390 ST / 390 STS
Graco 395 ST / 395 STS
Graco 450 ST
Graco 455 ST
Graco 490 ST
Graco 495 ST
Graco 190 ES (select versions)
Graco Ultra 600 (select versions)
Select legacy “Ultra / Ultra Plus” ST-series variants
Select GM 3000 / LineLazer 3000 (where ST-style pump is fitted)

What is the Graco 235703 Pump Repair Kit?

It’s an OEM packing / pump repair kit that refreshes the wear components of the pump’s fluid section—restoring pressure, reducing leaks, and improving prime & finish quality on compatible machines.

Key Benefits

OEM fit for ST / STS legacy pumps—no guesswork on sizes.
Restores performance if you’re seeing pressure drop, material bypass, or packing leakage.
Extends service life vs. running worn packings that score the rod or cylinder.

Kit Contents & Specs (Typical)

Component	Material / Type	Purpose
Upper Packings	Leather / UHMWPE (poly)	Seal around piston/rod; maintain pressure above fluid section
Lower Packings	Leather / UHMWPE (poly)	Seal at lower end of pump for efficient displacement
Throat / Wiper Seal	Elastomer	Keeps fluid in and contaminants out at the wet cup
O-Rings / Gaskets	Elastomer (assorted)	Restore static seals within the fluid section
Packing Glands / Spacers	Metal / Polymer	Correct stack compression and alignment

Note: Exact contents can vary by kit revision and pump series. Always match by part number 235703 and your sprayer’s model/series.

When to Use This Kit

Visible packing leakage at the throat or wet cup.
Pressure instability, poor atomization, or difficulty maintaining spray pattern.
Maintenance interval reached on heavy-use contractor machines.

Fitment Guidance

Check your nameplate for the exact model (e.g., 390 STS) and series/part number.
Legacy “ST / STS” pumps share architecture, but sub-variant differences exist—verify before purchase.
If your rod/cylinder is scored or pitted, consider a deeper overhaul or replacement pump assembly.

Installation Tips

Clean disassembled parts thoroughly; avoid lint and debris in the packing stack.
Pre-lube leather packings and follow the correct stack order & orientation.
Torque fasteners to spec; tighten packing nut only to the point of sealing and re-check after break-in.

Frequently Asked Questions

It fits 390 ST / STS and 395 ST / STS legacy variants. Modern 390/395 models with different pump families may use different kits—check your exact series and pump part number before ordering.

Persistent dripping at the throat, difficulty building pressure, pulsation, rough spray pattern, or frequent re-priming typically indicate worn packings/O-rings.

If the rod/cylinder is scored or pitted, packings will fail prematurely. Inspect surfaces during teardown—if damage is present, replace the affected parts or consider a complete pump assembly.

Basic hand tools typically suffice. Follow Graco’s service manual for your pump. Proper cleaning, lubrication, and torque are essential for a long-lasting repair.

Prime with appropriate fluid, run at low pressure to wet and seat the packings, then gradually increase pressure. Re-check the packing nut after initial use and adjust if needed.