Easy hydraulic question

[stravis]

This should be a simple one, but I know very little about hydraulics. I've used hydraulic implements quite a bit, but have never worked on them.

I have a 2009 John Deere 5101E. I was recently given a "free" 12' disc harrow. I had to replace the tires and hydraulic lines. I took the old lines off yesterday and took them into NAPA today to get new ones made. I should have gone to my JD dealer as these folks didn't seem to know what they were doing. Anyway, they've built the lines, but I've got a few questions.

1. The couplers that they put on them were the ISO type. Is this correct for my tractor? NAPA had no idea which one's I needed. I called my dealer parts counter, but they were out to lunch and the fella that I ended up talking to told me "ISO" type, but didn't seem to sure of it.

2. Do I need to use some thread tape when connecting these to the piston on the harrow?

3A. Do I need to "prime" the lines in any way? What I mean by this is obviously the lines are full of air. When I first hook them up, do I need to fill them with fluid to minimize the amount of air or will it just prime itself during the first use?

3B. I noticed the cylinder itself had some water in it when I took the original lines off. I know the cylinder works fine, but it had been sitting for a while. I really don't want any water or contaminated hydraulic fluid being piped into my tractor. Knowing that, should I hook one side up and flush the cylinder and hoses out into a bucket until fresh fluid starts flowing, then refill my tractor hydraulics to the right level?


Thanks in advance for your replies!

 

[LD1]

1. The couplers that they put on them were the ISO type. Is this correct for my tractor? NAPA had no idea which one's I needed. I called my dealer parts counter, but they were out to lunch and the fella that I ended up talking to told me "ISO" type, but didn't seem to sure of it.

I am not sure what you mean by "ISO" fittings???

2. Do I need to use some thread tape when connecting these to the piston on the harrow?

There are three main types of fittings, Flare, o-ring, and pipe thread. The Flare and o-ring fittings use no sealer. The pipe fittings need sealer.

3A. Do I need to "prime" the lines in any way? What I mean by this is obviously the lines are full of air. When I first hook them up, do I need to fill them with fluid to minimize the amount of air or will it just prime itself during the first use?

Typically it will prime itself the first time you use it

3B. I noticed the cylinder itself had some water in it when I took the original lines off. I know the cylinder works fine, but it had been sitting for a while. I really don't want any water or contaminated hydraulic fluid being piped into my tractor. Knowing that, should I hook one side up and flush the cylinder and hoses out into a bucket until fresh fluid starts flowing, then refill my tractor hydraulics to the right level?

How much water are we talking here??? If you could drain it out BEFORE you hool up the hydraulics, what little bit of moisture that is left isnt going to hurt you MANY gallon system.


Thanks in advance for your replies!

Maybe some others that know a little more can elaborate on what an ISO fittings is???? I know a bit about hydraulics and all, but some of the terms and acronyms I dont.

I have heard of AN fittings and JIC fittings, some are 37 degree flare, some are 45, O-rings are straight threaded, pipe fittings are taper (NPT), etc. But if the "ISO" fittings are just flare fittings, they need no sealer.

 

[stravis]

Thanks for responding so quickly.

1. Follow this link. Store Locator | NAPA Online
That is the coupler he put on both ends. The catalog we looked at to find these said ISO type, but the description in the link doesn't say anything about it. It does, however, say John Deere new type, which I would think would be correct. Any idea?

2. This is the end piece that they used. Store Locator | NAPA Online Do I need thread tape on this before I screw on the coupler? The other end of the hose that goes directly into the hydraulic cylinder has the o-ring type, I assume, as it has an o-ring on it.

3B. As I unhooked the old line from the cylinder, water came out for a second (maybe a pint, if that), then the hydraulic fluid that came out was milky. I let it drain into a bucket as much as gravity would take out. I have no idea how much more is in there, but it couldn't be much. I just thought it might be a good idea to flush it out with the nice clean fluid that is in my tractor rather than let the contaminated fluid get pushed into my tractor's system.

 

[oldnslo]

The threads on these are 1/2" NPTF which is National Pipe Thread Fuel so yes they do require some form of thread sealant.
The ISO designation is International Standards Organization. On quick disconnects they use ISO form A, Form B etc. So saying they are ISO is not enough information to determine what style of fitting that is being discussed.

P.S. Double check that the quick disconnects are the correct style for your JD before installing them on the hoses. over the years I believe JD has used more than one style.

Roy

 

[LD1]

Thanks for responding so quickly.

1. Follow this link. Store Locator | NAPA Online
That is the coupler he put on both ends. The catalog we looked at to find these said ISO type, but the description in the link doesn't say anything about it. It does, however, say John Deere new type, which I would think would be correct. Any idea?

2. This is the end piece that they used. Store Locator | NAPA Online Do I need thread tape on this before I screw on the coupler? The other end of the hose that goes directly into the hydraulic cylinder has the o-ring type, I assume, as it has an o-ring on it.

3B. As I unhooked the old line from the cylinder, water came out for a second (maybe a pint, if that), then the hydraulic fluid that came out was milky. I let it drain into a bucket as much as gravity would take out. I have no idea how much more is in there, but it couldn't be much. I just thought it might be a good idea to flush it out with the nice clean fluid that is in my tractor rather than let the contaminated fluid get pushed into my tractor's system.

Neither one of the links you provided work (at least not for me).

They only link me to the NAPA store locator, and NOT to a part description.

If the end that goes in the cylinder has o-rings, no sealant required.

So that only leaves two options for the other end if the dont have an o-ring. As mentioned, pipe thread (NPT, NPTF) require sealant. If they are an AN or JIC style flare fitting, no sealant required.

But for what it's worth, if in doubt, use the sealant anyway. It will do no harm if you use it on Flare fittings. But if you do indeed have pipe threads and do not use it, they will leak.

 

[stravis]

I appreciate the help, folks. I put it all together tonight. No leaks and the couplers worked fine, so they must be the right one's.

I did try to flush the system as best I could. I wasn't able to do so until it was clean, but I did get some more water and milky fluid out. Finally, I hooked it up and ran it. I do notice now that the sight glass for the hydraulic fluid has some bubbles on top, which I would assume would be from the remaining water. I'm guessing that's ok as it would only be a very small amount in comparison to the massive amount of hydraulic fluid in the tractor. Am I right? It was just hard to let any contaminated fluid get in my system. It was so clean. I hadn't used the hydraulics since new so the fluid in the sight glass looked fresh as a daisy.

 

[Discount Hydraulic Hose]

As mentioned above, the ISO simply means International Standards Organization. The ISO has published standards and specifications for, among other things, several common varieties of hydraulic quick disconnect couplers.

When people say "ISO Couplers," they are usually referring to:

ISO 7241-1 Series A Hydraulic Quick Couplers

or

ISO 7241-1 Series B Hydraulic Quick Couplers

Both ISO 7241-1 couplers above have similar performance qualities, with the Series B being a newer design than the Series A.

Two other popular couplers with ISO specifications are:

ISO 5675 Agricultural Interchange (aka "Pioneer") Hydraulic Quick Couplers

and

ISO 16028 Flushface Hydraulic Quick Couplers
(commonly found on Bobcats and other skid steer loaders)

This is not necessarily an exhaustive list of ISO couplers, but these four are the ones most likely to be found on tractors and other farm equipment.

The useful thing about ISO specification is interchangeability. If a coupler is fully compliant with ISO specifications, then it should be 100% compatible with other manufacturers couplers that are built to the same specification.

 

[Discount Hydraulic Hose]

The threads on these are 1/2" NPTF which is National Pipe Thread Fuel so yes they do require some form of thread sealant.

You'll get a lot of different opinions on this, but NPTF (National Pipe Tapered Fuel) is actually designed to seal without the need for thread sealant. Most people I know still use a thread sealant anyway.

With hydraulic systems, Teflon (PTFE) paste is preferred over the tape, because it is less likely to cause debris in your hydraulic fluid. Again, you'll get a lot of different opinions on this one, too. The advice I'm giving you here is what you'll hear from most manufacturers and hydraulic "experts." In the field, of course, a lot of end users have developed their own opinion based on their own individual experience.

 

[JB4310]

NPTF (National Pipe Tapered Fuel) is actually designed to seal without the need for thread sealant.

http://www.ring-plug-thread-gages.com/ti-NPT-vs-NPTF.htm

"NPTF threads are designed to screw together. They are designed to have interference at the roots and crests of the threads on both the major and minor diameters. This interference should cause no assembly problem. The thread deformation caused by the interference fit and the wrench tightening is designed to make a dry mechanical seal."

This explains it, the hydraulic shop always refers to pipe thread as interference thread.

My question is how many times can they be reassembled and still have a mechanical seal?

JB

 

[J_J]

For NPT threads a sealant compound or Teflon tape must be used for a leak-free seal. For NPTF no sealant is needed for a sealing.

NPT- National Pipe Thread Taper- ANSI B1.20.1

The NPT type fittings do have a limited number of connection and re-connections, as the threads crush each other and after awhile they will begin to leak.