Cannot Stop Jinma BH Hose Connection Leak

[Smalljobs]

I have another leak as shown in this picture. It's not easy to repair this one without removing a cylinder. When the BH was new last year, it leaked right away so I replaced the O-ring seal. The leak returned right away. Today I removed the O-ring and found it cut and split despite my care with cleanliness and lubrication when I repaired it last year. I installed another O-ring and used a gasket cement on both sides. It still leaks. The sealing surface looks OK on the hose end but I can't see the surface on the rigid steel transfer tube. I'd have to completely remove the tube to see it.

My thinking is to pick up another hose and another tube during my next trip to China. Another plan would be to buy adaptors from Ronald at Ranch Hand and make my own hose. I already did that with another hose it worked great. I'd probably bypass the steel tube and go all the way to the cylinder.

Does anyone have any better ideas?

 

[mrmikey]

Any chance you can go with a slightly bigger o ring, either diameter or thickness, different material maybe something a bit harder....Mike

 

[Smalljobs]

Good idea. Maybe a harder (higher Durometer) O-ring will do the job. I'm getting pretty good at removing the cylinder to expose that junction.

 

[Smalljobs]

I think there is something fundamentally wrong with this connection. During these two repair attempts, I've disconnected other hoses and reused the seals or swapped with new ones and there are no leaks. That's the way it's supposed to be, but this ONE connection refuses to seal.

 

[Bob Rooks]

I suspect the threads of the tube connector piece is not concentric or parallel with the ORFS hose connector. An O-ring that consistently splits is being wire drawn by leaking hydraulic oil.

 

[Smalljobs]

Bob, I knew you'd come thru!. The o-ring was not split as if I took a razor and cut the cross section. It had sort of a helix spiral laceration. I spent 30 years in the high pressure valve industry and suspected this was a bad surface finish that I could not see or something else. I think you nailed it. That seems to reinforce my idea of eliminating that joint entirely. If I can buy a new tube and hose while I'm in China I'll be all set. Otherwise, I'll use Ronald's adaptors and make my own hose from the control valve all the way to the cylinder.

I don't want to spend more time around this joint.

 

[Rich Waugh]

I thought that joint used a bonded washer, not an O-ring?

 

[RonMar]

Are you sure the hose end is not rotating when you tighten the threaded collar? That is a tough spot to work, and chinese pachine work being what it is, those surfaces might be a little rough. IF the hose end rotates when you tighten, the two surfaces working with the Oring in between may be damaging the oring which then distorts unevenly under pressure and leaks... I have had mine apart there to swap things around when I reversed the valve and it is a PITA the work there, but mine went back together without a problem.

I had the same thought though, that if I ever had an issue with that area, i would change it all out for a single point to point hose...

 

[Smalljobs]

Ron - As you know, the hose is really stiff in that area. I start the hose nut by hand and go as far as possible before using two wrenches. The hose does not rotate.

 

[Brad_Blazer]

If you still want to try another O-ring, try a "double seal" profile. It will seal against a different part of the surface and has double sealing surfaces. McMaster-Carr has them.