Backhoe Metric Thread O-ring Flat Seat Hydraulic Hose Fittings (Chinese standard)

[traktorz]

First - a Chinese paradox:



Not all Chines made equipments are genuine metric, such as this adapter on our LW-7 (LW7U10) backhoe. The hydraulic oil tank thread is 3/4" UNF, while the return hose from the valve block is metric M18x1.5. (Note: Unfortunately the obligatory O-ring is missing in this picture).

As you can see, it is derived from ORFS, but in metric and with the inner wall removed. Therefore, it's no inner edge preventing eg. a broken o-ring from enter into the pipe. The fittings are very compact, very reliable, repeatable and easily leak-proof, carrying some of the advantages from the ORFS standard. The only problem is that very few or almost zero hydraulic shops (outside of China) can help you making a spare hose.

It's the importers that are to be blamed, if not carrying a stock with adapters or ideally these metric hose fittings for crimp attachments. Each delivered backhoe should be supplied with a pair of adapters for M14x1.5, M16x1.5, M18x1.5, M22x1.5, in order to overcome the most acute hose problems. If not able to live up to that modest requirement, rather specify JIC or BSB fittings to enter the western world for all Chinese made backhoes, and leave those exotic fittings for the China market only. The western world have enough pipe and hose standards already is the message I often face, when trying to get a custom hose made in a hydraulic hose shop. Fortunately, the importers of Jinma and Foton and Chinese backhoes are very helpful in our country.

However, the importers do sell spare hoses of the same part number, which is fine if you're not into modifying your backhoe yourselves.
You might want to increase the area of some hoses, since adding a spin-on tank return filter. Maybe adding an extra hydraulic function for a thumb, or an extra function for a hydraulic tiltable planning bucket.

However, there aren't that many product numbers that needs to be imported and stored (preferably at a hose services in cooperation with the backhoe importer):



It seems that theses China Metric Female Flat Seat Fittings belong to the national standards: REF. JB/T 988 and REF. GB/T 9065.3 which can be found at:
Chinese Standards Search


Metric Thread Flat Seal

• 10311 - O-RING METRIC MALE FLAT SEAT --- REF. JB/T 988
• 20211-T - METRIC FEMALE FLAT SEAT --- REF. GB/T 9065.3
• 20211 - METRIC FEMALE FLAT SEAT --- REF. GB/T 9065.3
• 20231 - 30° METRIC FEMALE FALT SEAT --- REF. GB/T 9065.3
• 20241 - 45° METRIC FEMALE FALT SEAT --- REF. GB/T 9065.3
• 20291 - 90° METRIC FEMALE FALT SEAT --- REF. GB/T 9065.3

 

[Bob Rooks]

Proprietary maybe, but not paradoxical.

The LW-6 hoe that I purchased in '06 came with a large assortment of 14mm ORFS (male & female) X JIC male, several of which were helpful when I installed the return line filter. If you need adapters, I recommend two places:

Adaptall Inc. - Specialists in the Conversion of Hydraulic Adapters & Fittings

Discount Hydraulic Hose.com

As a side note, the 90° fitting you have pictured is an O-Ring Boss (ORB).

And another: Adding an external function requires a valve stack with power-beyond capabilities. The Chinese hoes don't have that. You can purchase a replacement valve stack with power-beyond from Prince and Surplus Center.

 

[traktorz]

Thanks for the links, but unfortunately none have any useful adapter to match the REF. JB/T 988 and REF. GB/T 9065.3 Chinese standards.

We need a flat face seal female adaptor, ideally with a swivel to keep the O-ring in place when tightening.

Regarding the photo above of the 90º elbow, I think that 3/4" corresponds to Flareless #12 SAE/ORB. (Thanks! I just learned about ORB. Dash numbers and ORB are not that popular, BSP is mostly used around here).

P.S.
Lacking power-beyond capabilities can be challenging. Maybe borrow a function from one of the stabilizers or parallelisation? It's not that we have an immediate need yet.

We were interested in that capability, about the time when we bought the LW-7 last year. There is a company in Sweden who specifies the backhoe and equips it with western fittings and Parker Hanifin cylinders and an European valve kit with power beyond. They do offer a hydraulic tilt planning bucket as an option.

There are always pros and cons.

 

[Bob Rooks]

Maybe borrow a function from one of the stabilizers or parallelisation?

That would work if you used PO check valves on the stabilizers.

Parker - DUAL PILOT OPERATED CHECK VALVES

 

[traktorz]

That would work if you used PO check valves on the stabilizers.

Parker - DUAL PILOT OPERATED CHECK VALVES

Thanks! Good idea!
Or perhaps should I start looking for something like the Prince Flow Control Valve - RD-150-8 0-8 GPM 1/2" Pressure Compensated Flow Control Valve - Top-Ports? I could tap some of the flow for an extra function.

=======================================

But maybe, I should now steer this thread back to the topic on Chinese "Metric Thread O-ring Flat Seat Hose Fittings"

Here's an example to solve a problem in an non-orthodox way. I simply needed a M22x1.5 Chinese Metric O-ring Flat Seat Hose Fitting for the suction line hose of my backhoe.



It's connecting to the hydraulic oil tank suction strainer port:

 

[psj12]

TRY: MARYLAND METRICS 'HOME PAGE'

 

[traktorz]

TRY: MARYLAND METRICS 'HOME PAGE'

However they imply a one-stop shopping site for metrics, I still doubt seeing these Chinese fittings outside of China. The resource to find these rare fittings should be at the importers of Chinese tractors and backhoes, but in Scandinavia this isn't the case from my own experience.

It seems this isn't an uncommon problem; A search on this site found eg. these example threads from the past. Unfortunately, often non-orthodox solutions are the only available path for the end user.

Ref:

• Jinma Fittings - tractorbynet.com
• Meteric fittings? - tractorbynet.com
• Hydraulic fittings on Jinma backhoe (jw03) - tractorbynet.com

 

[traktorz]

Non orthodox solution in making metric flat face seal fittings

Sometimes the wizards at the hydraulic shop can make wonders, such as the first time we needed to replace a broken hose of the tilt cylinder for our Front End Loader TZ04D-404.

The Chinese metric o-ring flat face seal press fittings are absolutely absent from the Scandinavian market, probably all outside of China. The only solution is to go back to the importer of the Foton & FEL, Kellfri in Skara, Sweden and ask for a direct factory made hose replacement. Unfortunately, they are not within driving distance (more than 600km), while well equipped hydraulic shops are within 100km distance.

However, our hydraulic shop did replace the nut from the ORFS press fittings with a METRIC nut:
ORFS 9/16"-18 nut replaced with M14x1.5mm nut. (9/16" ~ 14.3mm)
A genious move that I've realized first later when looking up the parts lists used for the press job. The result gave us a hose that fit and hasn't caused us any problems since last year.

Recently, another hose broke, this time for the boom cylinder of the backhoe, which has ISR 2-8-40(MPa) labeled on the hose (121 cm length) and has one straight and one 90 degree angled M16x1.5mm metric o-ring flat face press fittings. Consequently, I'm now wondering, if a similar technique can be used to find a suitable metric nut to fit an existing flat face ORFS fitting?

Is it possible to replace the nut for the ORFS 11/16"-16 with a nut for M16x1.5mm. (11/16" ~ 17.4mm)? (Without the need for an adjustment in a milling machine?)

P.S: The adapters on the picture below M14x1.5 (Male) <-> M16x1.5 (Female), is an example to show how these fittings look like. As mentioned earlier in this thread they are not ORFS, since they are metric (ORFS are inch only), furthermore these Chinese fittings lacks also the inner support wall for the o-ring. New tilt cylinder hose on top, the broken hose below.

 

[Affordable]

There are adaptors that convert the ORFS to JIC, however those fittings are not cheap to buy, we have a company here that can make replacement hoses for most of the chinese equipment now,

Tommy
Affordable Tractor Sales
'Your Jinma Parts Superstore"
Home of compact Jinma, Foton, and Koyker Tractors and Parts, Wood Chippers, Backhoes - Affordable Tractor Sales Company

 

[traktorz]

It's good to hear that in the U.S. there exists a possibility to make replacement hoses. I guess chinese equipment are more proliferated in the U.S. than in Europe.

Adaptors are most welcome to ease the problems with replacing these exotic hoses in the field, which press fittings are non-exixtent outside of China, at least to our experiences in Europe.

Adaptors wish list:
Chinese metric flat face (M14, M16, M18, M22 female) -> ORFS (male) adapters
Chinese metric flat face (M14, M16, M18, M22 female) -> JIC (male) adapters
Chinese metric flat face (M14, M16, M18, M22 female) -> BSP (male) adapters

NOTE:
Just to straighten up the nomenclature; The chinese metric o-ring flat face seal fittings should not be called ORFS. ORFS are specified in inch only, never in metric. Furthermore these metric chinese fittings have only a single wall groove for the o-ring, a simplified design cheaper to manufacture. The o-ring groove for ORFS has also an inner wall, reducing the risk of a broken o-ring to get sucked into the hose and contaminating the hydraulic system.

P.S.
One Swedish distributor of chinese backhoes with foresight, specifies the more common BSP standard fittings on all hoses, valve block and hydraulic cylinders they imports. Those backhoes obviously costs more here, but eliminates the aftermarket hazzle to find a spare to a broken hose.

P.P.S.
Another Swedish distributor of chinese backhoes imports the LW-6, LW-7, LW-8 backhoes as is, with these obscure or infamous chinese metric o-ring flat face seal fittings. Hence they need to stock direct hose replacements in various thickness, lengths and fittings.