800-456 is a lower packing assembly used to seal the piston rod in the pump fluid section of compatible Airless Sprayer 740I and 740IX models. It prevents fluid bypass on the intake side, supports priming, and ensures reliable pump performance.
| Part Number | 800-456 |
|---|---|
| Part Description | Lower Packing Assembly |
| Brand | Airless Sprayer |
| Fits | Airless Sprayer 740I, 740IX |
| Condition | New |
The 800-456 Lower Packing Assembly is an OEM replacement seal component for the pump fluid section of Airless Sprayer 740I and 740IX models. This assembly includes the lower packing (often a V‑packing or U‑cup) that seals the piston rod on the intake (inlet) side of the pump. It helps create the vacuum needed to draw paint from the container into the pump cylinder and prevents air from being pulled into the fluid system.
Over time, the lower packing can wear, harden, or become contaminated with dried paint, leading to poor priming, loss of suction, erratic spray, and reduced pump efficiency. Replacing the lower packing assembly with the 800‑456 restores the pump's ability to draw and hold prime, ensuring consistent material delivery.
| Intake sealing | Seals the piston rod during the suction (inlet) stroke |
|---|---|
| Priming support | Helps create vacuum to draw paint from the container |
| Prevents air ingestion | Blocks air from being pulled into the pump cylinder |
| Hard starting / no prime | Pump runs but will not draw paint or build pressure |
|---|---|
| Loss of suction | Pump loses prime easily or spits air |
| Paint leaking from weep hole | Visible leakage around the piston rod area |
| Visible wear or damage | Cracked, flattened, or hardened packing during inspection |
Part 800-456 is compatible with the following Airless Sprayer models. Always verify with your machine's parts diagram before ordering.
| Brand / Model | Component |
|---|---|
| Airless Sprayer 740I | Lower packing assembly (pump fluid section) |
| Airless Sprayer 740IX | Lower packing assembly |
When replacing the lower packing assembly, these related components are often inspected or replaced at the same time.
Replace both upper and lower packings as a set for balanced sealing.
Inspect for scoring, corrosion, or bending; replace if damaged.
Check for deformation and replace if needed.
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