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 | kwschumm
Join Date: Feb 2003 Posts: 5764 NW Oregon 
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2004-04-18 83514
I want to crack open and reroute some hydraulic hoses to make installing and removing my backhoe a little easier. I haven't worked on these hydraulics before and know I need to relieve the pressure before doing this work, but is there anything special to be aware of? How tight do the connections need to be? Do they need to be torqued to some particular value?
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 | DRankin
Join Date: Jan 2000 Posts: 5116 Northern Nevada
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2004-04-18 83521
Cool! when did the B/H arrive? ....
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| kwschumm
Join Date: Feb 2003 Posts: 5764 NW Oregon
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2004-04-18 83522
It arrived about 10 days ago. I've used it to dig out some stumps and excavate a small garbage dump and it's been great! My only regret is not getting it with the tractor. I found that when removing the backhoe the PB loop that you have to connect was very difficult to hook up without removing the backhoe seat. I want to reroute it a bit to make it easier. ....
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 | hardwood
Join Date: Dec 2002 Posts: 3583 iowa
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2004-04-18 83524
I've really never known if there are torque values for hydraulic couplers thresaded onto hose fittings, We try to not overtighten them. the JD "O" ring type couplers are tight enough when the base of the coupler contacts the base of the hose fitting, the "O" ring is at proper compression at that time. Pipe thread type couplers and hose ends only need to be tight enough to not leak, overtightening will distort things in extreme cases. On JD 4000 tractors with the engine off, moving the remote lever to both positions will relieve the pressure. Machines with hydraulic hoses sitting in the hot sun will generate real high pressures in the lines form expansion of the fluid being hot. Our metnod might not be an approved cure, but we simply take two wrenches and loosen the coupler from the hose end just enough that a small amount of fluid can escape. It doesn't take much probably less than a teaspoon full to relieve the pressure. Caution, only loosen it enough that it drips out not squirts out. On some systems that have extra long hoses I've installed a pipe "T" somewhere in the line with a high pressure ball valve that can be released more easily than loosening fittings. Hope this helps. Frank. ....
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| kwschumm
Join Date: Feb 2003 Posts: 5764 NW Oregon
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2004-04-18 83525
Thanks, Frank, that helps a lot. Since these are all JD factory parts I'll assume they have O-rings and try that. ....
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 | oneace
Join Date: Mar 2004 Posts: 1490 south central pa 
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2004-04-18 83538
just make sure you use some sort of thread sealed either teflon tape or pipe dope on all pipe fittings. 37 degree jic fittings i tighten them till they are tight you will know when that is. o-ring seals you can only tighten so much till the two faces meet. if your hoe is run off the power beyond circut there really is not pressure when the tractor is not running because it automaticly relives it self due to being an open center system. good luck it is all very easy to do. ....
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| TomG
Join Date: Feb 2002 Posts: 5406 Upper Ottawa Valley
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2004-04-19 83593
There are torque tables for hydraulic fittings. When new fittings are properly installed and tightened sealer usually isn't needed. Over tightening fittings makes them leak and then sealer is the only cure. If used, sealer should only cover the upper third of threads to avoid exposing it to the oil flow. It can break off and become an obstruction.
There are a bunch of installation rules for fittings as well as steel lines and hose to prevent premature failures. No time to summarize them this morning but maybe I'll get back to them. ....
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| oneace
Join Date: Mar 2004 Posts: 1490 south central pa
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2004-04-19 83658
sorry tom but to get a pipe tread fitting to seat proborly you all most always have to use some tipe of teflon sealler. If you knew how many fittings i put together in one day your head would spin. ....
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 | beagle
Join Date: Jan 2004 Posts: 1333 Michigan
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2004-04-19 83679
Hydraulic fittings are available with two types of pipe fitting threads, NPT, and NPTF. The NPTF threads are supposed to be able to be sealed without teflon tape. The NPT fittings require tape.
In my barn, they both get tape. ....
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| TomG
Join Date: Feb 2002 Posts: 5406 Upper Ottawa Valley
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2004-04-20 83696
There are several methods other than pipe thread. Irrespective, I meant only to point out that I think sealant is optional and that there is a right way to use it.
Myself, I use the stuff for used fittings but may not for new fittings since I don't like cleaning it off threads if I'm going to reuse fittings. If I were working commercially I'd probably use it since happy customers wouldn't want to pay for the time it takes to check for leaks and one that ended up with a leak wouldn't be happy at all.
For my education maybe somebody could point to a fitting manufacturer's requirement for sealant or a service manual procedure requirement or if tractors come from the factory with tape or other sealant used--could be but I just haven't seen them. Torque tables are given for fittings (not that they're usually used) but torque values aren't appropriate if tape is used.
I hope the routing and installation issues here don't get lost is what I think of as a sideline subject. ....
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