Hydraulic QA Coupler Sizing Questions

[Porchfan]

Hey Everyone.
I recently had a 3rd function remote added to my B2650. I want to replace the capped ends of the lines at the bracket the dealer put on with a couple QA couplers in place of the caps.
The dealer (or kit) put/had female to female nipple/adapter at the bracket on each line that is two different sizes. The end towards the valve is a bigger size then the capped end size. The valve side of the nipple is ~0.75. The implement end of the nipple is ~ 0.675.

QUESTIONS:
(1) What's the deal with that?
(2) What size QA coupler do I get on the implement end. I think I'll go with male QA ends.

Here are pics of both measurements

 

[LD1]

Thats just an adapter fitting.

Looks like a NPT to JIC bulkhead fitting. 3/8" NPT to 1/2 (-08) JIC fitting

Male Pipe (NPTF) x SAE 37° Flare (JIC) Bulkhead

You need fittings with 3/8 NPT to connect onto where the cap is.

And it appears they used teflon tape. Get rid of that and use a sealant or paste

 

[varmint]

Before you install MALE ends, do a little checking. I am no expert, but virtually all the remotes I have seen had female couplers. 3/8" hydraulic lines are likely the size of most implements you would use with that tractor.

 

[bumperm]

Here's a handy chart that'll help identify which quick coupler is which. I printed it out and took it out to the tractor (grin). Size is reasonably close when you print the chart 1/1.

http://www.discounthydraulichose.com/v/vspfiles/downloadables/qd_sizechart.pdf

 

[jimmysisson]

Are you talking about using a coupler in place of a cap? Won't that leave the line open? Maybe I misunderstand you?
Jim

 

[murphy1244]

Here's a handy chart that'll help identify which quick coupler is which. I printed it out and took it out to the tractor (grin). Size is reasonably close when you print the chart 1/1.

http://www.discounthydraulichose.com/v/vspfiles/downloadables/qd_sizechart.pdf

I have the same chart. Handy sob it is.

 

[the old grind]

Thats just an adapter fitting.

Looks like a NPT to JIC bulkhead fitting. 3/8" NPT to 1/2 (-08) JIC fitting

Male Pipe (NPTF) x SAE 37° Flare (JIC) Bulkhead

You need fittings with 3/8 NPT to connect onto where the cap is.

And it appears they used teflon tape. Get rid of that and use a sealant or paste

:thumbsup::thumbsup: (All 10 ) Use one male & one female on the bracket, and one of each on the hoses, so they'll go together correctly every time you connect.

M and F Q-D couplers will seal when disconnected. (as best they can)

There seems to be 'micro-beads' in everything from toothpaste to laundry detergent these days. If there are any in your Teflon pipe dope they'll likely end up in your hydro filter. A worked-loose scrap of Teflon tape will as likely find a more troublesome place to go to.

 

[varmint]

I have, and often see, a pair of female couplers, so that no matter what you are hooking up, you can get the flow path you want. But in a perfect world, the male and female would also be fine. Leaking shouldn't be an issue.

 

[SweBota]

And it appears they used teflon tape. Get rid of that and use a sealant or paste

Why would you need any sealant of any kind on a hydraulic fitting? Is that due to some flaw in the NPT threads? We use BSP,JIC,ORFS and Metric fitting and none of them require any extra sealing.

I have, and often see, a pair of female couplers, so that no matter what you are hooking up, you can get the flow path you want. But in a perfect world, the male and female would also be fine.

There seems to be 2 schools of thought on this; most Ag equipment have all 1/2" female couplings on the tractor and male on the implements. This is also how the factory rear remotes are delivered on (newer?) Kubotas. But a lot of CUTs have 3/8" couplings and most of those seem to use the one male/one female principle for each circuit. At least thats how all my Kubotas has been delivered, a 20-year model span.

I have decided to use the first method in the rear and the second for everything up front. That way I can borrow 3pt equipment from farmers around me, and still stay "CUT standard" for FEL and front mount equipment.

/Marcus

 

[LD1]

Npt requires sealant. Jic and o-ring fittings do not.

 

[Porchfan]

Thanks Everyone.
On the teflon tape, I hear you. I think they put that crap all around the new 3rd function valve. I guess that's what you get when you spend $950?
At the 3rd valve, the two QA couplers on the lines are female. On the valve block are two male fittings. I take it these are closed when disconnected otherwise 3000PSI of fluid would be spewing everywhere? They're identical to the 4 fittings for the loader bucket up down/curl hydraulics. The one time I used my tractor without the loader, I just capped these with rubber boots with no issues. They are tucked away so no worries.

Here's a picture of one of the QA male fittings on the valve.



It looks like ISO_7241 series B
ISO 7241-B Quick Disconnect Nipple

Even with rubber boots on the ends when I don't have the implement on the loader, I would think these are more easily damaged than female?
Either way, I need to be a little careful not to damage these. Maybe add a female adapter that is hard capped on the other end. Seems to me that would be more rugged and less prone to abuse

 

[SweBota]

Npt requires sealant.

I understand that, but why use it then if its unsuitable?

Jic and o-ring fittings do not.

Nor does BSP, metric, ORFS or any other type I have encountered. I would consider it a requirement for high-pressure connections not to rely on sealant...

/Marcus

 

[Porchfan]

On leaks and sealants. I just found this. Seems pretty informative. http://www.sbp.noaa.gov/resources/engineering/docs/Hydraulic_Systems_Leak_Free.pdf

 

[varmint]

Npt requires sealant. Jic and o-ring fittings do not.

Good point LD1- obvious if you know it, maybe not obvious otherwise..

 

[LD1]

I understand that, but why use it then if its unsuitable? Nor does BSP, metric, ORFS or any other type I have encountered. I would consider it a requirement for high-pressure connections not to rely on sealant...

/Marcus

I am not saying not to use sealant. Sealant IS required for NPT. Just not the tape kind. Patricals/shreds of tape that find its way into a hydraulic system will mess up valves. Liquids and pastes won't.

 

[varmint]

As a side note, my brother owns a company that manufacturers geo thermal valves and equipment. When he started it, pretty much all the items used NPT for fittings. Years ago, they started switching to an O ring seal, sort of like the Shark bite fittings... The warranty claims for the NPT leaks vs. the O rings are like 100-1. If the market didn't insist on them, they wouldn't even offer the NPT.
Of course, on a tractor, the mechanical connection is also important, due to the stresses placed on hoses and such.

 

[LD1]

99% of all NPT leaks I have encountered are improper installation.

While I agree that JIC fittings are better for hydraulics, I dont like o-rings as much. O-rings fail. But NPT fittings can hold back thousands of PSI on hydraulic systems. 100psi water and air systems should be a cakewalk.

 

[SweBota]

I am not saying not to use sealant. Sealant IS required for NPT.

We are talking past each other here, I'm asking why use NPT fittings if they aren't suitable for hydraulics. If they need additional sealing they clearly are not...

I haven't seen a single NPT fitting on any of my Kubotas, so they seem to be used for add-ons only, or ?

I'm not familiar with your type of O-ring fittings either. Standard here is BSP or JIC fittings. Both are flange-sealed. Against a block thread I would add a metal bonded o-ring to a standard fitting.

If there is a better solution, why not use it?

/Marcus

 

[LD1]

We are talking past each other here, I'm asking why use NPT fittings if they aren't suitable for hydraulics. If they need additional sealing they clearly are not...

I haven't seen a single NPT fitting on any of my Kubotas, so they seem to be used for add-ons only, or ?

I'm not familiar with your type of O-ring fittings either. Standard here is BSP or JIC fittings. Both are flange-sealed. Against a block thread I would add a metal bonded o-ring to a standard fitting.

If there is a better solution, why not use it?

/Marcus

I am sure there are NPT fittings on your kubota somewhere. NPT fittings ARE suitable for hydraulics.

Lets break it down.

1. NPT CAN be used for hydraulics
2. NPT requires sealant.
3. There are 3 common types. Liquid (like loctite 545), Paste (like the white PTFE paste), and Teflon tape.
4. Dont use tape on hydraulics cause shards of it can mess up valves.

O-ring fittings come in 2-types here. ORB, and ORFS. ORB is the most common. And the threads are the same as a JIC male fitting. But instead of the cone to seal, they are just a flat end like a NPT fitting. BUT, at the base of the threads there is an o-ring, and a mating machined flat surface on the female part.

I dont think I have EVER seen a hydraulic cylinder with JIC ports. So that pretty much leaves NPT, or ORB fittings to adapt to whatever hoses you choose. IIRC, MY kubota has NPT fittings on the cylinders, and on the quick couplers. And the loader valve is ORB fittings. The hoses are JIC.

So.....you have a cylinder with an NPT to JIC adapter. And a valve with an ORB to JIC adapter. And the hose has JIC fittings to go between the two adapters. So in 1 simple circuit, there are 3 fitting types. And they are all pretty common here.

 

[downsizingnow48]

My Kubota quick couplers are NPT female.