Torque Settings for Hydraulic Pipe

[jp2code]

Recently a stick or stump bent the J-pipe on my Kubota L4400 (#170 in the image below)

I have a new one ordered. The bolt (#180 in the image) was so tight that I had to push with my foot on my 18-inch wrench.

Does anyone know what it should be torqued to when I reassemble this?

 

[Henro]

I do not know what the spec might be, but my limited experience tells me it should require less than you are able to apply by hand with a normal wrench, unless maybe you are a 90 pound weakling, not meaning to look down on those with limited physical abilities, as I have noticed after passing 70 a few years ago I do not have the moxy I once did...

 

[rScotty]

Was the bolt torqued too tight? Or was it that the gaskets had adhered to the joining faces and breaking that glue joint took extra torque?
In these banjo fittings it's the gasket that does the work, and there are a variety of gasket types - copper, aluminum, crushable, composite, and even encapsulated O ring type.

I can't tell without a flow diagram just what that pipe does. My guess from the looks of the parts and where it is mounted is that it is there to transfer fluid back to the sump if the relief valve goes off. If so, then being a high pressure application, the gaskets be single use; best practice is to use new ones.

Some of the composite banjo gaskets have a sort of varnish coating that with time and heat makes them stick like glue to both surfaces. If so, that could be the cause of the extra torque - you'd probably spot that if you had to scrape anything off the metal faces that bear on the gasket.

But considering it's job of lining of compressing two gaskets to be parallel to 4 metal faces and hold a few thousand psi of hydraulic pressure along with a big temperature swing....well, it also wouldn't surprise me to find that hollow banjo bolt has a fairly high torque. It certainly has a special duty to perform.

Now I'm getting curious.... does the workshop manual talk about any special torque there? If not, I think it's worth a call to the Kubota tech dept.
rScotty

 

[jp2code]

I don't have a workshop manual. This thread is hoping someone does.

I didn't notice any paint, Loctite, or flaking hydraulic fluid on anything. It all looked pretty clean.

I don't think that I ever posted a picture of the part.

 

[Tractor Seabee]

Here is what I see in the diagram:

170 is the pipe with a thread on one end and a banjo fitting on the other. 200 is the o-ring which seals the threaded end of the pipe. Usually that type tread is a straight thread. If it was a tapered pipe thread there is no reason for the o-ring

180 is the bolt for the banjo which is a gasketed joint, gasket being 190, qty of 2, one on each side of the banjo. Usually these are copper are some other soft alloy.

Gaskets and 0-rings are considered one time parts and a new ones should be ordered. The parts person should have pointed this out and included in the order. The bolt probably had locktight on it, hence hard to remove.

Due to the o-ring and gaskets the torque is probably good to follow. It is very easy to deform or cut an o-ring with too much torque.

Lacking torque values; tighten the pipe end snug up and rotate to its proper position for the banjo. It would take a whole extra full turn to make any tighter which is probably too much. the banjo gaskets are accessible to where you can tighten more if it leaks. Use a standard box wrench or ratchet socket on it till tight. Use locktight on the thread.

Under tight is easy to add more torque, overtight; you need new gaskets and/or o-rings

Hope this helps. The pipe may come with the torque specs or wheedle it out of the dealer service manager. That is why I always but the shop manual on new stuff as I do 90% of my own work.

Ron

 

[jp2code]

Hey Ron,

The pipe actually has NO threads on the end. It just has a groove for the o-ring. I have another pipe on order from Messeck's. Their shopping cart neglected to tell me to put an o-ring into the cart, but looking at my order on their website, I see that I did add one along with 2 copper gaskets.

In the meantime, I did my best to straighten this hydraulic pipe. It bends easy, like soft brass. I got it together and added some tranny fluid (all of it was pumped onto the ground). Without turning the tractor on, fluid is already leaking out.

I guess I need that new o ring. I'll even compare the old hydraulic pipe to the new one whenever it arrives on Wednesday and report back with pictures. Everyone likes pictures.

 

[Tractor Seabee]

Hey Ron,

The pipe actually has NO threads on the end. It just has a groove for the o-ring. I have another pipe on order from Messeck's. Their shopping cart neglected to tell me to put an o-ring into the cart, but looking at my order on their website, I see that I did add one along with 2 copper gaskets.

In the meantime, I did my best to straighten this hydraulic pipe. It bends easy, like soft brass. I got it together and added some tranny fluid (all of it was pumped onto the ground). Without turning the tractor on, fluid is already leaking out.

I guess I need that new o ring. I'll even compare the old hydraulic pipe to the new one whenever it arrives on Wednesday and report back with pictures. Everyone likes pictures.

That pipe is actually the Tank (T) line that takes the fluid back to the pump sump, so it is a low pressure line probably never exceeds 300# if that. Ron