Matching Hydraulic Hoses

[JeffroL]

I've got an old John Deere 500C backhoe and I've removed 6 hydraulic hoses (with much effort). One had a pinhole leak and the others looked very rough. So I just pulled them off. The problem is that I have no idea how to match these hoses to new ones. I do not know their max operating pressure for example. I found 3500psi hoses at Tractor Supply, but don't know if they are sufficient. The hoses appear to be 1/2" diameter, but then I learned the outer diameter may be the same for 5/8" vs 1/2" hoses. So I have no idea now.

Help! Is there any way to find the specficaitons for these lines? Photos of the *very* similar hose I found at Tractor Supply. But again I have no idea if these are correct - and I do NOT want to do this twice

-Jeff

 

[Fallon]

I'm unaware of any tractors that operate significantly over 2,500psi. Some skid steers run at 3,500psi, excavators can be double or triple that. So basically a 3,500psi rated hose will be fine on a tractor.

You could cut one of the old hoses in half with a hacksaw & measure.

 

[JeffroL]

Shoot..mistyped that. It is a backhoe not a tractor. I don't know if that makes a difference in the hydraulic pressure

 

[LouNY]

I woundn't worry much about the pressure rating as the threads, are they npt, bsp, sae?

 

[JeffroL]

I woundn't worry much about the pressure rating as the threads, are they npt, bsp, sae?

That's the kind of question I'm not educated enough on the subject to answer. I did carefully compare the hoses vs. the ones at tractor supply and the threads look identical. I even "threaded" them together by holding them side by side and the threads connect perfectly.

 

[/pine]

The pictures of the hose ends are "male pipe" (NPTF) ...note the chamfer...this will allow the use of female pipe swivels (NPSM)

note:

National Pipe Straight Mechanical (NPSM) fittings are similar to NPTF, except they have a parallel thread and seal on an internal 30 degree seat.

A properly chamfered NPTF male fitting will mate with a NPSM female.

Steel Fittings - DiscountHydraulicHose.com

here is a size chart:

https://www.discounthydraulichose.com/v/vspfiles/downloadables/thread_guide.pdf

 

[JeffroL]

The pictures of the hose ends are "male pipe" (NPTF) ...note the chamfer...this will allow the use of female pipe swivels (NPSM)

note:

Steel Fittings - DiscountHydraulicHose.com

here is a size chart:

https://www.discounthydraulichose.com/v/vspfiles/downloadables/thread_guide.pdf

Thanks very much, that site shows exactly what I have, looks like a standard part to me.

 

[JeffroL]

Just a quick update. I was able to replace the leaking hydraulic hoses and 7 others that looked very worn. Zero leaking fluid now. There were a couple however that were extremely hard to access. Hard to know how to squeeze a wrench into some places to break free a 30 year old fitting!! Any tips / tricks?

 

[GLyford]

I have heard of, and seen video of, people using a chisel on the corner of the flats to loosen or tighten fittings in tight spots, but have never done it myself. If you think about it, most hoses don't get taken apart and put back together a lot, they mostly get put on once and off once and tossed with the bad hose so a few chisel marks isn't likely to cause bigger issues down the line.

I tried finding the video again that shows it being done, but haven't had luck so far.

Your other option is taking a 2nd hand or import wrench and grinding off the outside enough that it can get at the fitting. It will be weaker, but how often do you have to change hoses? Grinding a new "fitting" wrench every few years is probably worth it to reduce frustration.

 

[Fallon]

I have heard of, and seen video of, people using a chisel on the corner of the flats to loosen or tighten fittings in tight spots, but have never done it myself. If you think about it, most hoses don't get taken apart and put back together a lot, they mostly get put on once and off once and tossed with the bad hose so a few chisel marks isn't likely to cause bigger issues down the line.

I tried finding the video again that shows it being done, but haven't had luck so far.

Your other option is taking a 2nd hand or import wrench and grinding off the outside enough that it can get at the fitting. It will be weaker, but how often do you have to change hoses? Grinding a new "fitting" wrench every few years is probably worth it to reduce frustration.

Had to do the chisle thing on a hydraulic filter on my new L4060 on the first change. No room to get any leverage on a strap wrench. It's ugly & kind of destroys the fitting(filter) in question, but often works.