JIC hose/fitting parts catalog confusion

[Applachian]

My Parts catalog for a Case 580SL is giving me some trouble. It specifies fittings in thread dimension only 7/8-14, 1 1/16-12, and so on. It does not specify hose sizes anywhere. Between loader and various backhoe circuits I have found I have 3 main sizes 3/8 for stabilizers, 1/2 for all loader functions and swing, 5/8 hoses for boom dipper and bucket. I know these sizes with 100% confidence. Again, manual specifies only connectors, only by threading.

My issue is that all the thread specs correlate to a jic size above the hose size. When converted, I get sizes such as “ORB -12 to JIC-12 90* ok….fine…..makes sense…..hose is 3/4 then…..nope…5/8. And so on with all other sizes. I don’t want to take things apart right now. Do I need crimp hose ends that go from -10 hose to -12 jic and -8 hose to -10jic, why would Case make that decision with every connector on the machine?

 

[Shimmy1]

I'm just going to throw a WAG out here, as someone that grew up around Case backhoes. The up-sized JIC connection is about the same inside diameter of the hose, whereas the same size connector would essentially be smaller, and be restrictive. Just a guess, maybe someone has a better idea.

 

[Applachian]

Anyone know the specs on that^^^ 10 10 and 12 12 is far more common than 10 12 and 8 10, and cheaper. Same fitting 5/8 straight through is $10, 3/4 straight through is $15, and to change size from 5/8 to 3/4 is $19.

 

[willie59]

Well, I'll prolly butcher this trying to explain it, but yes, there are "jump size" fittings that deviate from the norm of fitting to hose size, could be jump up, or jump down. In this case, the flow of oil to work the dipper or boom of a loader/backhoe for example, that's a good amount of oil flow to make that happen. And by design a 5/8" (-10) hose would be sufficient. However, the -10 (5/8") ORB adapter fitting has a smaller ID than a 5/8" dash 10 hose, that would make that fitting a restrictive orifice, which can create heat. Solution, jump size. Use a -12 (3/4) ORB adapter and a 5/8 hose with a -12 JIC female fitting. Now the adapter and the hose fitting ID is closer to the ID of the 5/8" hose eliminating the orifice restriction that would be caused by a -10 ORB adapter fitting. Does that make sense.

 

[Applachian]

Sounds like the concensus is that Case needed small flexible hoses and high flowing fittings. If there’s no error in the manual I’ll just buy the jump size fitting. I appear to have a few non-original hoses. The only 3/4 hoses on the backhoe are new ones. And the only new ones are 3/4. Seems like a viable explanation is the local shop (to the previous owner) must not have had jump size fittings on hand.

 

[Applachian]

All straight male jic hose to hard connections are the same over size. Hard lines match hose sizes.

 

[willie59]

All straight male jic hose to hard connections are the same over size. Hard lines match hose sizes.

You are correct. Typically fitting dash sizes match hose dash sizes. But there are exceptions, and in my explanation the exception would be the manufacturer designed the hydraulic system to eliminate any restriction at the adapter fittings by jumping the adapter and hose fittings up one size.

 

[Shimmy1]

Anyone know the specs on that^^^ 10 10 and 12 12 is far more common than 10 12 and 8 10, and cheaper. Same fitting 5/8 straight through is $10, 3/4 straight through is $15, and to change size from 5/8 to 3/4 is $19.

And an extra $100 is going to break the bank?

 

[Applachian]

Nah. Just wasn’t sure if something was wrong or I was misunderstanding something. That was an expensive endeavor for the manufacturer over thousands of machines. But it must be worth it.

 

[Andy K]

I know your already have your answer but an easy way to remember is to take the dash number and put it over 16 and reduce the fraction. That will give you the size of the fitting & hose. Older Ford tractors use -14(7/8) on -12 (3/4)hose. Parker makes -14 in the series 43.

8/16=1/2
10/16=5/8
12/16=3/4
14/16=7/8