Any issues with mis-matched hose sizes?

[jim_wilson]

While my BH77 hoe was removed from the tractor over the winter - I managed to whack one of the outrigger hydraulic hoses and rupture it. So I've got to replace the hose. I've got Parker hose - and a the correct crimper and fittings to replace the hose , but one end of the hose has a 90 degree long-drop type fitting - which apparently Parker does not make in the configuration I need. It's a 9/16-18 thread - JIC 37 degree seat fitting, and on the original Kubota hose it goes to a 1/4" hose. Parker only makes that fitting to go on a 3/8" hose.

What I'm wondering is: If I make up a replacement hose assembly using 3/8" hose - instead of 1/4" - is there any detrimental effects? Everything else in the system uses 1/4" hoses.

Not sure why Parker doesn't make a fitting in the configuration I need , they have it in some of their other fitting/hose lines and so do some of the other manufacturers.

 

[SSdoxie]

Problems of flow restriction and or back pressure can result when downsizing from a larger to a smaller hose, but in this case going from smaller to larger will have no detrimental affect.

 

[BHD]

I would see no problem replacing 1/4" hose with a 3/8"

 

[jim_wilson]

Thanks for th input - I've got the hose and just need to pickup a couple of fittings and I'll get that hose replaced with some 3/8"

 

[goeduck]

There will not be any issues on an outrigger hose feeding a single cylinder. Maybe one outrigger is faster than the other but no big deal. Where I would be concerned is if I had parallel cylinders (as with an FEL) on the same work port. Then you could get some twisting motion.

 

[jim_wilson]

There will not be any issues on an outrigger hose feeding a single cylinder. Maybe one outrigger is faster than the other but no big deal. Where I would be concerned is if I had parallel cylinders (as with an FEL) on the same work port. Then you could get some twisting motion.

That's what I was really wondering - if the slightly larger hose would make the hydraulics faster. It will be interesting I suppose to compare the two outriggers to see if the one with the 3/8 hose is quicker than the other now. The fittings that the hose connects to on each end (valve block and outrigger cylinder) - look like they're easily large enough to pass the flow from a 3/8" hose. It's the 1/4" hose that is the flow restriction.

 

[TractorGuy]

Practically every hose on my backhoe has step up or step down fittings. These fittings are much more expensive than straight #8 to #8 or#10 to #10, etc. Not sure why a MFG would do this due to the extra cost.

The first hose I had made the shop made it a smaller hose but the same size connection fitting. This is on one side of my loader and I have not seen any binding or anything from that but it worried me. In that case it had a #8 hose going to #6 connections. I reckon the connection diameter being #6 limits the flow to 3/8". Now if they put a 1/4" hose on that side I think it might cause binding for that function on the loader. On all subsequent hoses I have asked them to stick with what came on it except the AC. If you reduced the flow from one side to the other on a loader I think you could run into problems.

In your case I think goeduck is correct that you may have a slower movement for that side.

 

[LD1]

Honestly it seems about every tractor or piece of equipment I have owned or worked on.....they step the fitting sizes up one from the hose. IE: -4 hose with -6 fittings, -6 hoses with -8 fittings, etc.

The real expensive ones are on my backhoe. -12 hoses but stepped up to -14 fittings. and 7/8" fittings arent very common.

Always just assumed it had to do with Flow. Fittings are restrictions. And stepping them up one size reduces that, while still using smaller (more flexible) hoses. And in many hoses, smaller also means higher pressure rated.

That said, when replacing hoses, I usually upsize the hose also, to match the fitting size. As mentioned....much cheaper to pay a tad more for larger hose, but save alot on the fittings.

That said, you dont have to limit yourself to just parker fittings.

Since you need a LONG 90 fitting, and its JIC......That certainly isnt threading right into the cylinder. There is likely a NPT-JIC or ORB-JIC adapter threaded into the cylinder. Perhaps one could have gotten a longer one of those, or even a longer adapter that has the 90 as part of the adapter that way next time you blow a hose, a simple straight JIC fitting on the hose.

Hoses with just straight JIC fittings are usually the cheapest. And since hoses are usually what need replaced, I try to spend the money on the fittings to get what I need and keep the hoses simple and cheap.

 

[jim_wilson]

Honestly it seems about every tractor or piece of equipment I have owned or worked on.....they step the fitting sizes up one from the hose. IE: -4 hose with -6 fittings, -6 hoses with -8 fittings, etc.

The real expensive ones are on my backhoe. -12 hoses but stepped up to -14 fittings. and 7/8" fittings arent very common.

Always just assumed it had to do with Flow. Fittings are restrictions. And stepping them up one size reduces that, while still using smaller (more flexible) hoses. And in many hoses, smaller also means higher pressure rated.

That said, when replacing hoses, I usually upsize the hose also, to match the fitting size. As mentioned....much cheaper to pay a tad more for larger hose, but save alot on the fittings.

That said, you dont have to limit yourself to just parker fittings.

Since you need a LONG 90 fitting, and its JIC......That certainly isnt threading right into the cylinder. There is likely a NPT-JIC or ORB-JIC adapter threaded into the cylinder. Perhaps one could have gotten a longer one of those, or even a longer adapter that has the 90 as part of the adapter that way next time you blow a hose, a simple straight JIC fitting on the hose.

Hoses with just straight JIC fittings are usually the cheapest. And since hoses are usually what need replaced, I try to spend the money on the fittings to get what I need and keep the hoses simple and cheap.

I sort of figured the same thing - upsizing the fittings from the hose ID means that you're less likely to restrict flow at the fitting. I'm not fully familiar with hydraulic circuit design - but that does make some sense.

You are correct - the hose end that has the 90 degree long drop elbow - goes into the valve block - and there is a JIC fitting screwed into the valve itself that the hose threads onto. So I could probably find a different fitting to screw into the valve block that would allow me to maybe use a different 90 degree hose fitting and stick with 1/4" hose. I'll have to delve into the Parker catalog a little more and see what other options I have. I might be able to use something other than a 90 degree fitting there also - but the hose setup going into the valve block is pretty tight - and the hose coming out of the valve block does take an almost 180 degree turn to feed out to the stabilizer cylinder. So - I'd like to stay somewhat in line with the original installation , because it will just look cleaner , and I've read the recommended procedures for hose routing and what Kubota did there is exactly in line with the recommended hose routing procedures.

I'm sticking with Parker because I've already got the crimper and dies and hose and some of the fittings.

I just got sort of shafted on this one particular hose setup because for some reason Parker doesn't have the correct fitting available to do a direct one to one replacement using the OE size 1/4" hose.

If there were some other brands of fittings that would safely interchange onto the Parker hose and would properly crimp in the Parker crimper - I would try that out. I just couldn't find anything after doing a little research on it.

 

[SilentJ]

Problems of flow restriction and or back pressure can result when downsizing from a larger to a smaller hose, but in this case going from smaller to larger will have no detrimental affect.

Agreed. Bigger is always better.