1970 ford 3550 fitting leak for backhoe u

   / 1970 ford 3550 fitting leak for backhoe u #1  

rajandura

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May 18, 2023
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5
Tractor
Ford 3550
Recently purchased a 1970 ford 3550 loader backhoe. One of the hydraulic hoses for the bucket curl blew my first time using it off the trailer. It was right in the middle of the hoses, and the rest didn't look great either, so I decided to replace them all. $1500 later and 10 gallons of hydraulic oil, plus 150$ in tools to make the repairs, and now I have a fitting leaking at the valve. It's leaking where the check valve threads into the valve body for the boom raise/lower. I thought maybe I didn't tighten it enough, or perhaps put a defective oring on it. I removed it, checked the threads, cleaned it, installed a new oring, and threaded it back in. It did seem like it tightened....then went loose for a turn or so, then tightened back again. I reinstalled everything and low and behold it's still pouring out from this connection. What gives? Appreciate any help you can offer.
 
   / 1970 ford 3550 fitting leak for backhoe u #2  
If you’re referring to the backhoe boom, it is just sealed by a hard oring, but I assume you figured that.

A picture would be good
 
   / 1970 ford 3550 fitting leak for backhoe u
  • Thread Starter
#3  
The fitting is one of the Two hoses that runs to the backhoe control valve under the seat that has a restrictor fitting on it. The other various hoses use a flare to mpt fitting(red). One of these hoses, the one that is leaking (pink) goes to the crowd cylinder on the boom. I've been researching diagrams online, and it seems these two hoses use two different restrictors.(blue/green) Is it possible that if they're in the wrong position it could leak at the connection similar to a blown oring...? The threads are the same but if they function differently perhaps the fluid is getting pushed past the oring somehow?
 

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   / 1970 ford 3550 fitting leak for backhoe u #4  
Not likely
 
   / 1970 ford 3550 fitting leak for backhoe u
  • Thread Starter
#5  
Not likely
Any suggestions for fixing the leak? Could I try double o rings or are these possible to tap and retread...it didn't leak at the fitting before I changed out the hoses
 
   / 1970 ford 3550 fitting leak for backhoe u #6  
You could try doubling the oring, but not likely that will fix it. You could try just a regular fitting to see where the problem is exactly. The standard fitting is highlighted below or you can order from New Holland. This way, you can figure whether it is the fitting that is buggered up or the valve body.

87301330
-replaces #325059 HYD CONNECTOR 7/8''-14, 37 Degree x 7/8''-14, O-Ring

Also, there is this listing for the fitting or you can try a tractor dismantler.
 
   / 1970 ford 3550 fitting leak for backhoe u
  • Thread Starter
#7  
So I swapped out the restrictor valves, the one that was leaking was noticeably longer than the other and probably wasn't seating all the way. Swapped out with new orings and no more leak. Well, at least not from that fitting. As luck would have it, another fitting began leaking. Pulled it, changed the oring, reinstalled, and knock on wood no leaks as of yet. I hope the investment in new hoses/orings keeps me up and running for awhile!
 
 
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