How do you torque hydraulic lines?

BloomingtonMike · Dec 14, 2005

I installed my 3rd SVC loader arm hydraulic oil lines tonight on my JD 3320. They are the metal oil lines (hard lines). In the instruction manual it said to torque them? How do you torque those metal lines? You need a line wrench to tighten them to eachother. My torque wrench is just a socket wrench type.

_RaT_ · Dec 14, 2005

Perhaps a crows foot type attachment for your torque wrench. Its an open end wrench basically with a 1/2" or 3/8" socket opening. I used them for adjusting and torqueing the valves on my old Datsun.

Mike_Lipke · Dec 14, 2005

If they don't give values, then the word "Torque" is interchangeable with the wore "tighten".
You are torquing a fastener everytime you tighten it, whether you are measuring the torque or not.

SCB · Dec 14, 2005

General rule of thumb for us at one of the largest aircraft mfg. is if accessability prohibits use of a torque wrench on hydraulics, you tighten until the fitting bottoms out. Then you will turn it two more flats(1/3).

JoeL4330 · Dec 14, 2005

Our old rule of thumb was "finger tight plus a half turn ...30 ft.lbs, as I recall"

turnkey4099 · Dec 14, 2005

Yeah, they don't need to be really "reefed" on. The internal design takes care of the sealing with reasonable tightening.

Harry K

dent8 · Dec 14, 2005

Tighten 'til it strips then back off 1/4 turn. /forums/images/graemlins/crazy.gif
Dennis

CT_Tree_Guy · Dec 14, 2005

Tighten 'til it strips then back off 1/4 turn /forums/images/graemlins/crazy.gif

Dennis, that is a GOOD one! Welcome to TBN, you're going to fit right in, I can tell. /forums/images/graemlins/laugh.gif

I've never measured the torque on any hydraulic line or coupler, just make it good and snug - well, halfway between snug and tight as he$$. I used to be "torque wrench happy" until I realized that MOST torque specs that you find in any manual are just based on a universal torque chart that relates torque to the diameter of the bolt/size of the nut. Once you have a "feel" for what those torque values are, you can work much faster. For example, I used to use a torque wrench on spark plugs, which are usually around 15 ft/lbs. Now is just go by feel - make sure the little metal gasket gets fully crushed, then add a hair more. Without a gasket, just make them good and snug.

Of course there are MANY fasteners that should (MUST?) be torqued with a torque wrench. Head bolts, crank pulleys, intake manifold bolts, main bearing caps, piston rod caps, stuff like that.

EddieWalker · Dec 14, 2005

I'm in agreement with everyone else. Just tighten them until they won't go any further. They self seal when tight. If they leak,then you need to get them tighter. /forums/images/graemlins/grin.gif

Eddie

slowzuki · Dec 14, 2005

I think most plug torque specs now have to do with protecting aluminum heads eh? I have a few torque wrenches but rarely use em, I've broken enough bolts now I have a good feel for where I should be! At least they've all been rusted bolts I'm trying to unscrew.

( Tighten 'til it strips then back off 1/4 turn /forums/images/graemlins/crazy.gif

Dennis, that is a GOOD one! Welcome to TBN, you're going to fit right in, I can tell. /forums/images/graemlins/laugh.gif

I've never measured the torque on any hydraulic line or coupler, just make it good and snug - well, halfway between snug and tight as he$$. I used to be "torque wrench happy" until I realized that MOST torque specs that you find in any manual are just based on a universal torque chart that relates torque to the diameter of the bolt/size of the nut. Once you have a "feel" for what those torque values are, you can work much faster. For example, I used to use a torque wrench on spark plugs, which are usually around 15 ft/lbs. Now is just go by feel - make sure the little metal gasket gets fully crushed, then add a hair more. Without a gasket, just make them good and snug.

Of course there are MANY fasteners that should (MUST?) be torqued with a torque wrench. Head bolts, crank pulleys, intake manifold bolts, main bearing caps, piston rod caps, stuff like that.

)