Street Elbow ok in Hydraulic application?

[John_Mc]

I recently had a log grapple added to my FEL. This required plumbing a hydraulic line from one of my rear remotes to operate the grapple. I asked of they could put some kind of elbow on the quick disconnect from the new hydraulic lines, so they would stick out too far to the rear (I was concerned that the connections not stick out far enough that they would interfere with my logging winch).

What they put on was a "street elbow" which looks as though it's designed for use with black iron pipe, rather than hydraulic hoses. Is this sort of plumbing acceptable for use in high pressure hydraulics? This wont get whole lot of constant flow with the grapple, just occasionally opening and closing. I suppose that may change if I added some other type of implement to the FEL that needed constant hydraulic flow, but I can't imagine what I'd be doing with something like that on this little tractor.

On of my reasons for asking is that one of the street elbows started leaking the first time I used it: it's a pretty good drip while the grapple is in motion opening, and a steady stream when the grapple reaches its opening limit. It's going to go back to the dealer who installed it to have this fixed. I'm wondering if I should insist on some other sort of fitting while it's in there.

Pics of fitting below (and grapple for those that are interested). Thanks for any advice/tips.

John Mc

 

[aczlan]

Hmmm, 150PSI working pressure rated elbow in a 2000+ PSI system, what could possibly go wrong...
I would want an elbow like this one in there:
Hydraulic Adapter, 8MP-8FP9 - For Life Out Here


Aaron Z

 

[dickfoster]

I recently had a log grapple added to my FEL. This required plumbing a hydraulic line from one of my rear remotes to operate the grapple. I asked of they could put some kind of elbow on the quick disconnect from the new hydraulic lines, so they would stick out too far to the rear (I was concerned that the connections not stick out far enough that they would interfere with my logging winch).

What they put on was a "street elbow" which looks as though it's designed for use with black iron pipe, rather than hydraulic hoses. Is this sort of plumbing acceptable for use in high pressure hydraulics? This wont get whole lot of constant flow with the grapple, just occasionally opening and closing. I suppose that may change if I added some other type of implement to the FEL that needed constant hydraulic flow, but I can't imagine what I'd be doing with something like that on this little tractor.

On of my reasons for asking is that one of the street elbows started leaking the first time I used it: it's a pretty good drip while the grapple is in motion opening, and a steady stream when the grapple reaches its opening limit. It's going to go back to the dealer who installed it to have this fixed. I'm wondering if I should insist on some other sort of fitting while it's in there.

Pics of fitting below (and grapple for those that are interested). Thanks for any advice/tips.

John Mc

If it were me, I wouldn't have any more work done there. Those people are dangerous.

 

[SPYDERLK]

Hmmm, 150PSI working pressure rated elbow in a 2000+ PSI system, what could possibly go wrong...
I would want an elbow like this one in there:
Hydraulic Adapter, 8MP-8FP9 - For Life Out Here
View attachment 465228

Aaron Z

Yeah, I wouldnt stand for it even tho I tested a 3/4" Class 150 fitting to destruction using a porta power -- popped at 7000PSI. I do have some Class 300 fittings on one of the Kubots, put on by a dealer. I complained but let them stay. I always go with the machined steel fittings for the mods I do.

 

[Gary Fowler]

I don't know if I would trust a dealer that put a 150 # fitting in a 2000+ PSI hydraulic system to work on this again without some personal supervision. That fitting would only be ok to use in a suction line but definitely not in the pressure side.

 

[John_Mc]

Thanks, guys. I had no idea what the pressure rating of a street elbow was. Where do you find the rating? do the symbols cast into the fitting have anything to do with it? I'm going to have a chat with the owner of the dealership, and would like to have some hard data to show him.

This was odd, since other hydraulic work they have done for me used regular hydraulic fittings even the other ends of these same hoses used appropriate fittings.

 

[Tractor Seabee]

Just the appearance indicates the fitting is a cast material. Those of us who have the background in piping know what it is at a glance it is a cast malleable iron fitting. WP is 125 PSI. You probably will not find the pressure rating on it. Cast iron fittings look similar but more massive and they have the rating cast in. Forged steel are rougher than the machined fittings but are available in many high pressure ratings with the rating stamped into them. Machined hydraulic fittings are that; machined from high tensile billet stock. Machined fittings are much smaller (outside dimensions) than forged of the same rating. Where you have a space problem the machined fittings are the way to go.

One advantage of hydraulics is that a failure will probably not send steel fragments flying but the hot oil can just as bad spraying at 2-3 K PSI through a fracture

Agree with all above comments; that is not a shop I will recommend or return too. The foreman should never have let that one happen. I always blame management more than the worker as they are not training and supervising properly.

Ron

 

[SPYDERLK]

Thanks, guys. I had no idea what the pressure rating of a street elbow was. Where do you find the rating? do the symbols cast into the fitting have anything to do with it? I'm going to have a chat with the owner of the dealership, and would like to have some hard data to show him.

This was odd, since other hydraulic work they have done for me used regular hydraulic fittings even the other ends of these same hoses used appropriate fittings.

You can look up pipe fitting Class on this site.

McMaster-Carr

 

[John_Mc]

Thanks, Ron, and everyone. I've been poking around some more, now that I know the search terms to use. I can find some rated at 300 PSI, and thought I saw one at 500, but can't find it again, so maybe I was looking at something else. A service guy is stopping by Tuesday afternoon to make repairs. I just sent a message to the Service Department person who set up the appointment with a picture of the parts in question and asked her to make sure he brings appropriately rated hydraulic fittings with him.

A more in-depth discussion will take place when I am at the dealership in person.

BTW - what are the chances that screwing the quick disconnects and other fittings on to these malleable iron parts has damaged the threads?

 

[Tractor Seabee]

The HUD parts should be OK as they are harder than the malleable and the malleable will expand/distort quickly if over tightened. That is one reason they are leaking.

Ron