Graco Ultimate Mx 695 Lo-Boy - Sprayer Pump Breakdown (246428)

Graco Ultimate MX 695 Lo‑Boy (Pump 246428) – Full Pump Breakdown & Parts Guide

If you're operating the Graco airless paint sprayer MX 695 Lo‑Boy, keeping its Chromex-piston pump (part 246428) in top shape is essential. This top-tier graco electric paint sprayer delivers professional-level results with minimal hard starting. The pump breakdown shown here aligns with the official graco paint sprayer parts diagram and graco parts list, giving you a seamless way to inspect, maintain, or rebuild your sprayer. With overlapping inventories like graco magnum x5 parts, it's also smart for fleet-wide servicing.

Pump Overview & Compatibility

• 246428 Displacement Pump is the heart of the flow system. It’s compatible with Ultimate MX 695 and 795 Lo‑Boy, Hi‑Boy, Stand units, and even some 1095/1595 models.

• Built for up to 3,300 psi, the pump features a hardened stainless cylinder, Chromex piston rod, and V-Max Blue packing—ensuring both fine finishes and heavy coatings can be handled flawlessly.

• Many internal parts cross-apply as graco magnum x5 parts, simplifying spare inventory across different sprayers.

Breakdown of Key Internal Components

Referencing the official paint sprayer parts diagram, here’s the internal layout (with reference numbers):

1. Rod & Crankshaft Gear

   • 249125 piston rod (chromex) is supported by a retaining spring and straight pin.

   • Crank gear (287054) and thrust bearing (180131) maintain alignment and smooth motion.

2. Pump Seal & Fittings

   • Jam nut (195150) and washer (115099) mount securely on the displacement rod.

   • Suction side includes an O-ring seal (117559) and swivel fitting (162453).

3. Pump Body & Cylinder

   • The main pump assembly holds all wear parts—packings, valves, springs—and connects via ¼"NPT fittings 

4. Drain/Hose & Control Manifold

   • Hose coupling, control manifold assembly (15H977 / 15E295), and drain valve are located just ahead of the gun connections.

OEM vs Aftermarket & Shared Parts

• Chromex piston rod and V-Max Blue packings are significantly more durable than aftermarket options; original Graco design outlasts them under heavy use 

• The rod kit 249125 and piston components are also included in graco magnum x5 parts, making float across units seamless.

• When servicing multiple mys, you can use OEM cylinders, valves, and fittings interchangeably.

Step-by-Step Repair & Rebuild Guide

1. Remove the pump – Detach suction tube, drain hose, and intake manifold.

2. Split the housing – Extract jam nut, rod washer, and pull out rod. Inspect bearing gear and seal rings for wear.

3. Rebuild the cylinder – Use an OEM packing kit (e.g. 18B260) to replace seals, packings, valve seats, pistons, springs.

4. Reassemble with factory torque – Tighten the jam nut and housing bolts to OEM spec.

5. Pressure-test flow – Reattach hoses, run pump on side pressure, test flow rate and check for leaks and pulsation.

Built-in paint sprayer parts diagram (from official Graco manual) provides torque specs and proper assembly order for each internal component 

Ordering Guide: What You'll Need

• Piston Rod Kit (249125) – Chromex rod with piston seals.

• Packing Kit (18B260) – Includes all packing seals and O-rings to rebuild the fluid section.

• Jam Nut & Washer (195150 /115099) – Ensure leak-tight connection.

• Suction Swivel Fitting (162453) – Standard ¼"NPT for hose attachment.

• Drain Hose & Manifold Tubing (244240) – Essential for cleaning and external flow.

• Complete Pump Assembly (246428) – Installed as a direct replacement, ideal for quick swap and minimal downtime 

Maintenance Best Practices

• Weekly: Lubricate packings with TSL fluid, inspect hose adapters and swivels.

• Every 500 hrs: Rebuild with rod kit and packing kit, check piston rod for scoring.

• Annually: Run a quicktest for pressure pulsation and flow rate to ensure proper assembly.

• Carry spares for quick repairs—especially rod kit, packings, manifold filters.

Integration with Electric Sprayers & Accessories

• The 246428 pump fits both Lo‑Boy electric paint sprayer MX 695 and similar electric manifolds.

• Suction tubes, drain adapters, and fittings are shared with graco sprayer accessories, including hoses, guns, and filters.

• A single cylinder rebuild kit can support both gas and electric Lo‑Boy units.

Final Takeaway

The Graco Ultimate MX 695 Lo‑Boy pump (246428) is rugged, serviceable, and critical for smooth high-pressure spraying. With OEM components and logic-informed rebuild steps tied to the graco paint sprayer parts diagram, you’ll maintain tight flow and finish quality. Add graco magnum x5 parts to your spare setup and ensure long-term reliability across all Graco sprayer platforms.