Thread identification
O-Ring Face Seal — ORFS (SAE J1453)
ORFS fittings seal with an O-ring set into a groove on the male's flat face, compressed against the female's flat seat. They are the leak-tightest common hydraulic connection and standard on most late-model excavators and loaders.
Identify it
Four checks at the bench.
- 01
Look at the male face: dead flat with an O-ring groove means ORFS
- 02
The female nose is flat with a smooth internal shoulder — no cone
- 03
Measure thread OD and pitch; ORFS uses fine UN threads one size class 'up' from JIC
- 04
Check the O-ring: 90-durometer, sized per dash — replace it whenever the joint is opened
Don't confuse it with…
- A missing O-ring makes ORFS look like a strange flat JIC — it will never seal without the ring
- Metric flat-face (DIN/Komatsu variants) can look identical; thread pitch tells the truth
- ORB is also O-ring sealed but at a port boss, not a face-to-face union
Reference
Size chart.
| Size | Thread |
|---|---|
| -4 | 9/16-18 UNF |
| -6 | 11/16-16 UN |
| -8 | 13/16-16 UN |
| -10 | 1-14 UNS |
| -12 | 1-3/16-12 UN |
| -16 | 1-7/16-12 UN |
| -20 | 1-11/16-12 UN |
A1 stocks it.
- ORFS Female Swivel Hose EndA1-WB-ORFS
- Interlock ORFS Female SwivelA1-4S-ORFS
- R15 Interlock ORFS FemaleA1-6S-ORFS
- ORFS ↔ JIC Adapter SeriesA1-FA-OJIC
Unsure even after the checks? Bring the fitting to the counter — gauging an unknown thread takes us about a minute. (817) 589-7101.
O-Ring Face Seal — ORFS (SAE J1453) — FAQs
Why do ORFS fittings leak after reassembly?
Almost always a nicked, aged, or missing face O-ring. Replace the ring every time the joint opens; we stock 90-duro kits at the counter.
Can I replace ORFS with JIC?
Only by changing both sides or using an adapter — the threads and sealing methods are incompatible. We stock ORFS-to-JIC adapters for mixed circuits.
Why did equipment makers switch to ORFS?
Elastomeric face seals survive vibration and repeated assembly far better than metal cones, so warranty leak claims drop.
Lou Einstein