Graco 104805 Back-Up Ring
The Graco 104805 Back-Up Ring is an OEM support ring that reinforces O-rings and seals, preventing extrusion and maintaining system integrity under high pressure.
- Use: Fits behind primary seals in pumps, valves, and spray systems
- Benefit: Extends seal life and reduces maintenance frequency
- Material: High-strength polymer/PTFE for durability
Graco 104805 Ring, Back‑Up – Essential Seal Support Element
Compatible Machines
- Graco fluid‑handling pumps and proportioners using backup ring supported seals
- Graco high‑pressure spray systems and finishing equipment with internal seal assemblies
- Graco service kits for surge tanks, filters and internal modules where backup rings are required
- Graco mobile and stationary equipment undergoing rebuilds of internal seal cavities
Product Description
The Graco 104805 Ring, Back‑Up is a precision‑engineered support ring designed to reside behind primary seals (such as O‑rings or lip‑seals) in demanding hydraulic, fluid‑handling and spray equipment. Its role is to reinforce the seal under pressure, prevent extrusion or deformation of the soft seal material, maintain seal geometry and thereby extend both seal and equipment service life.
Key Features
- Structural support ring: Positioned immediately behind the main seal to resist extrusion under high differential pressure.
- OEM‑specified component: Manufactured to match Graco’s internal cavity designs and material requirements.
- Compact design: Fits seamlessly into existing seal grooves without altering clearance or performance.
- Improves reliability: Helps minimize seal failure, leakage and maintenance interventions in high‑cycle systems.
- Ease of replacement: Installed during standard service intervals along with seal sets to maintain optimum performance.
Technical Specifications
| Specification | Details |
|---|---|
| Part Number | 104805 |
| Component Type | Backup Ring / Seal Support Ring |
| Function | Provides structural support behind primary seal elements |
| Material | High‑strength polymer or PTFE variant (industrial grade) |
| Service Environment | High‑pressure fluid modules, pumps and spray systems |
Applications
This ring is used in critical seal cavities of Graco equipment where soft seals alone might extrude, fail or deform under load. Typical use cases include fluid‑end modules of high‑pressure pumps, manifold blocks in spray systems, filter housings and surge tanks. By installing the 104805 ring behind the seal, the system maintains correct geometry, resists material creep and prolongs the service interval.
Performance Advantages
- Prevents extrusion of soft seal materials when subjected to high differential pressures.
- Maintains alignment of primary seals for consistent sealing performance.
- Reduces frequency of maintenance and replacement of seals, lowering downtime.
- Supports stable system pressure and prevents fluid or air bypass.
- Optimises equipment reliability by using an OEM‑matched support component.
Maintenance Tips
During rebuild or preventive service, remove the old backup ring and inspect the groove for damage or deformation. Ensure the new ring seats fully, clean and lubricate adjacent seal surfaces, then install the new primary seal behind it. Make sure the backup ring is undamaged, and having been properly seated, so it can perform its function of supporting the seal under pressure. Replace if you observe flattening, cracking or signs of seal extrusion to safeguard system integrity.
Frequently Asked Questions
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