Compatible Machines
The Graco 104103 Piston Compression Ring (listed by Graco as RING, CPRSN, PSTN) is used in hydraulically driven proportioner piston assemblies. The following machines are commonly associated with this ring—always confirm in the specific parts manual for your unit before ordering.
- Reactor 2 H-25
- Reactor 2 H-30
- Reactor 2 H-40
- Reactor 2 H-50
- Reactor 2 H-XP2
- Reactor 2 H-XP3
- Reactor 2 Spray Foam Rigs (hydraulic variants)
- Reactor 2 Polyurea Rigs (hydraulic variants)
- Graco Power Station–equipped rigs (where specified in manuals)
Part Details
Genuine Graco OEM ring designed to maintain piston sealing/compression in high-pressure pump assemblies. Typical catalogue callout: 104103 – RING, CPRSN, PSTN.
| Attribute | Spec / Notes |
| Part Number | 104103 |
| Description | Piston Compression Ring (RING, CPRSN, PSTN) |
| Typical Dimensions* | Approx. 83 mm ID × 90 mm OD × 3 mm thick (check your manual) |
| Application | Piston seal/compression element in hydraulic proportioner pump assemblies |
| Category | OEM Graco replacement part |
Why choose OEM?
- Maintains factory clearances and pump performance
- Compatible metallurgy and finish for piston/bore interface
- Supports longevity of packing sets and piston wear parts
Helpful Tips
- Replace associated wear parts (piston rings, packings, seals) together for best results.
- Lubricate per manual during assembly; observe ring orientation where specified.
- After installation, perform pressure/leak checks before returning to service.
Frequently Asked Questions
It is commonly listed for H-25, H-30, H-40, H-50, H-XP2, H-XP3 hydraulic units. Always confirm by checking your unit’s exploded parts diagram for the piston assembly and verifying 104103 is the called-out ring.
Reuse is not recommended. The ring experiences wear and heat cycling; replacing it during pump service helps maintain sealing integrity and pressure performance.
It’s good practice to inspect and often replace related wear items (piston packings, seals, retaining rings) at the same time. Consult your model’s service kit and maintenance schedule.
