Metric ORFS fittings

Blui · Sep 16, 2024

I have a chinese tractor 33.1kW(import name eurolepard 454) with Front loader. Steering is 100% Hydraulic.
Had some power steer hose damage caused by poor routing (stressed the wire braid when front axle pivots) (M18x1.5 thread ORFS)
Recently a right side fire from oil soaked wiring & a short took out a couple of hyd hoses. (M20x1.5 thread ORFS - close to 13/16-16)
In both cases of replacing hoses I had to re-braze new fittings onto the steel tube because the nearest ORFS size would not fit on account the tractor fittings had metric threads. I have verified with thread gauges.
New fittings are not very expensive, just more time to get tractor going again.

I have asked various suppliers from china for metric ORFS but no luck.
I need to remove my FEL to do some head work & would be handy to make some ORFS end plugs to keep the fluid in.

oldnslo · Sep 17, 2024

Where are the O-rings in those fittings? The ORFS fittings I have seen and used have a groove for the O-ring not a counterbore like those.

Maybe try Thomkins (spelling) or Parker. They both have a vast selection of fitting styles.

Tinhack · Sep 17, 2024

oldnslo said:
Where are the O-rings in those fittings? The ORFS fittings I have seen and used have a groove for the O-ring not a counterbore like those.

Perhaps you're thinking of BSP with O-rings or ORB fittings. Or even ISO 6149. The photo shows ORFS fittings. The O-ring fits into the counter bore not on the outside.

Another problem with small production Chinese tractors is they don't have to follow any standard. They typically use whatever hardware they have at the time or make their own.

oldnslo · Sep 17, 2024

Tinhack said:
Perhaps you're thinking of BSP with O-rings or ORB fittings. Or even ISO 6149. The photo shows ORFS fittings. The O-ring fits into the counter bore not on the outside.

Another problem with small production Chinese tractors is they don't have to follow any standard. They typically use whatever hardware they have at the time or make their own.

Tinhack
All of the ORFS fitting I have seen have a groove for the seal to sit in and not a simple counter bore. The ORFS seals are typically a very thin cross section and would get sucked into the flow path unless that is a tapered bottom counterbore.

Agree on no clue what Chinese use

Blui · Sep 17, 2024

Thanks for the discuss, below image of the pwr steer hose connection.
It is a face seal, completely flat & as noticed not a groove, just counterbore. Not an issue for the PS as it shouldn't go negative pressure.

I haven't removed the FEL hoses yet, preliminary thread measure shows 15.7mm & looks to be M16x1.5
I can make up some end caps with M16 fine nuts to apply some rigor-mortis to the FEL.

ptsg · Sep 18, 2024

Worst case scenario, cut those ends off. Get some DIN2353 compression fittings and be done with it with a more common fitting. You can either use the DIN2353 for the fittings for the hoses or adapt it to something else.