? about banjo hydraulic fittings, JD790

[RobS]

Tom, I found a spare banjo bolt finally. As you have already learned, it is 3/4-16 thread. I measured 1.055" across the hex flats and the length from under the head to the open end is 1.301. I have the part with me so if you want anything else from it let me know /forums/images/graemlins/smile.gif

 

[tomrscott]

Here are some pics of the JD790 hydraulic lines showing the banjo fittings if anyone is interested. The banjo fittings are at both ends of the green painted line shaped like a G laying on its back. The connection to the left is apparently pressure from the rockshaft housing, and the other end is the power line into the FEL control valve. The wrench size is 1.062" or 1 - 1/16". As we've said the bolt is a 3/4x16 straight thread.

I managed to order some right angle fittings that will be SAE8 O-Ring Males on one end and 1/2" tubing flareless bite fittings on the other end. Not cheap though, cost about $10 each! I can use these to replace this line with the lines that will feed the supply lines to my new TNT valve. I want to run the supply lines to the new valve in solid tubing and use hoses for the cylinder lines. So these are before pics, hopefully I will have some after shots in a week or two /forums/images/graemlins/wink.gif

 

[tomrscott]

Here is a view pulled back a couple of feet from the previous post so you can still see that line with the banjo fittings, but you can see that it is visible down between the seat and the right fender. The 3pt control lever and seat belt are right there. Getting at all this plumbing will require taking the seat out and the fender off and some of the other sheet metal around the controller. May even decide to take the wheel off and put the rig on jack stands. (The tires aren't filled, planning to cut up some steel weights, another project)

The lower port under the power connection to the FEL SCV is the tank return line and will probably require unbolting the FEL SCV to screw on the new right angle SAE8 fittings. Not enough clearance to spint the 90 ell in otherwise.

Anytway this gives you an idea where all this plumbing goes.
/forums/images/graemlins/wink.gif

 

[tomrscott]

Boy, I am realizing one huge advantage of the original banjo fittings over the SAE8 straight thread O-ring fittings that I plan to replace them with.

The banjo fittings make a "zero clearance" ell. In other words, when I use any other kind of ELL coupling threaded into the same port, I have to have clearance to spin the ELL into the port. Witn a banjo fitting the perpendicular branch doesn't spin, just the bolt head which requires no extra clearance, other than the wrench to turn it with, and with a box wrench that doesn't take much.

It is going to be pretty hard to get a standard fitting into a couple of the nooks and crannies up around the FEL SCV and the crankcase and transaxle. I will definitely have to disassemble more things than I would have to if I could use banjo fittings.

Looking at some of the difficulties of this today, I was seriously reconsidering buying new banjo lines, cutting them apart, and brazing new tubing onto the factory ends, and then bending it into the shape I need. Trouble is the line is a funky size that I don't think would nest into another standard size; I think it was .485 OD.

I wonder how hard it would be to make some homemade "banjo ends" that you could braze tubing into? I guess the "banjo" body has to have some clearance around the banjo bolt shank. Maybe you could drill it out with a bolt clearance diameter first, and then counter bore the back face with about 1/8" oversize drill to within 1/8" of the top face. It wouldn't have to be "banjo" shape, but could be more "brick" shape?

Humm....

 

[tejuban]

locate a "Tubes N Hoses" shop, they can supply you with the banjo fittings you may need and make up any hose you need.

 

[tomrscott]

Well, that's a real nice thought, but I haven't found it to be so. I have not found a single hydraulic tube hose or coupling supplier in the Portland Metro area that has ever heard of anyone selling banjo fittings, except the ready made lines I can order at the JD dealer.

Numerous attempts at google searching have turned up nothing useful. Parker Hannifin (one of the premier suppliers of Hydraulics) has only one obscure reference to banjo fittings in a table of recomended fitting torques. I found a place in India that will make banjo fittings in brass, a Brittish supplier that makes a very nice banjo elbow coupling to tubing bite fittings, but it uses BSPP or Metric threads and Metric tube diameters. Something similar in 3/4 x 16 threads and 1/2" tubing would be perfect. I've even emailed that Brittish company to see if they have ever heard of such a thing. see: http://www.indanc.com/steel-compression-fittings-06.htm

I would love to find that I am wrong, but I have been unable to find anything useful at all.

Now I am having second thoughts about the ability to use SAE8 Straight Thread O-Ring fittings too. These require an undercut face groove, kind of a complex shaped chamfer around the female port. Until I open up the banjo fittings on the JD I won't know for sure, but I'm betting that undercut is not going to be there. I can get a pilot shank cutter that will cut that port chamfer, but then I've got to worry about getting cutting chips in the system.

Maybe the best bet is buying John Deere banjo lines and cutting them up and brazing or welding new lines onto the JD ends...

 

[tomrscott]

It just occurred to me that you may have meant a business named "Tubes N Hoses", so I did a search on the name and found a lot of similar names.

I just emailed a place called "All Tubes N Hoses" in Phoenix AZ, but their web site wasn't much help.

I'll keep looking, maybe that will turn up something after all.

 

[tomrscott]

Finally found a Tubes N Hoses store in Vancouver WA, and Jason there was real nice and willing to help, but he called all his suppliers and neither he nor anyone he knows can find a source for banjo tube ends of any kind. He did offer that if I took my existing JD hard lines off, we could cut the lines and he could see if he could swage them up to be sleeve around the OD of 1/2" tubing so we could braze them onto new lines. He also said he had sometimes drilled the banjo knuckle out and silver brazed new tubing into the knuckle. The only thing with that is it seems like there wouldn't be much engagement between the tubing and the banjo end to make it very strong. This is not something I want springing a leak.

I am tempted to make my own banjo ends on the lathe. I haven't taken one apart yet, but I don't remember how the inside of the banjo knuckle is designed. I can drill a 3/4" hole through a piece of bar stock, and I can drill a 1/2" hole in the end with a bit of shoulder at the bottom, but there has to be some clearance around the banjo bolt inside the banjo knuckle. What I don't remember is if they get that by just drilling it oversize from the backside of the knuckle, depending on the copper washer to seal it, or whether the knuckle interior is larger ID than either the front or back face hole diameters. In the latter case, it is a bit harder to bore that banjo hole. If the back face can be counterbored to 7/8", leaving the last 1/8" 3/4" diameter, then the banjo hollow bolt would center fine in the 3/4" hole in the outside face and the counterbore would offer plenty of fluid flow inside the knuckle. It doesn't leave as much sealing surface on the back face of the banjo, but it would still probably work fine.

Maybe fabricating ends is not so unreasonable. I guess you could even make rectangular ones without a lathe. Just find some steel bar stock about 1.125" square, or maybe 1.25", cut pieces 2" long, drill a 3/4" hole about 9/16" from one end, counter bore that part way through with a 7/8" drill, then end drill the other end of the bar with a 7/16" drill through to the banjo hole, and then counter-bore that with a 1/2" drill, leaving a shoulder at the bottom. Braze some tubing in and you'd have an industrial strength banjo fitting. You could do some quick chamfering of the corners on a bench grinder. If you put it on a lathe, you could turn the tubing end down to say 3/4" or 11/16" OD.

I only need four of these, but gosh if they came out nice, I might use three more for the supply lines on the control valve too.

I have to say, the more I look at banjo fittings the nicer they seem to me. You get a right angle that is "universal" (doeesn't need to spin to thread into the hole) for minimum radial clearance, and it also offers the least height clearance too.

Plus it would be an excuse to get an oxy acetylene bottle set for brazing (I've got torches, hoses, and regulators passed down from my dad, but didn't get any tanks with them, movers wouuldn't move the tanks, even empty). Quimby is running a sale on ~3 foot long tanks for about $240 the pair.

Hummm... /forums/images/graemlins/ooo.gif /forums/images/graemlins/tongue.gif /forums/images/graemlins/wink.gif

 

[tomrscott]

I am here to tell you that as far as I can tell, no one in the US makes or sells braze-on banjo fittings anymore. I have exchanged countless emails with dozens of companies all over the US and the world!

I finally found a company in India who appears to make exactly what I am looking for:

http://www.indiamart.com/manjeetindustries/

They even show some banjo fittings with O-ring seats which would be preferable to copper crush washers because they re-seal better. The trouble is that they haven't responded to my emails.

So, one of the engineers I work with is from India and still has family there. He has offered to get someone to talk to this company directly. Maybe they just don't want to be bothered with a small international order.

First I have to get a quote with some part number information because there isn't enough info on the website to order from, and then he will get them purchased over there for me, and sent here, and we can pay securely in US currency.

I am going to get one shot at this, but if anyone is interested in getting some braze-on banjo fittings like this let me know and I will consider arranging a group purchase (I have also posted this to the Machine Builders Net). Depending on the cost, I would like to get about ten each of an SAE-8 banjo to braze-on to 1/2" OD tubing. If the pricing is real attractive, I may get a few extras of the SAE-8, as well as some SAE-6 to 3/8" ones for some future projects.

I will post more info here as I find out more. If the India connection doesn't pan out, I'll probably end up fabricating these, but I have decided they would be more work to tool by hand than I want to take the time for. I would rather buy them if I can. /forums/images/graemlins/smirk.gif

 

[notamustang]

Sounds like you have exhuasted almost all options. I would have given up when Parker or Earls couldn't have helped. /forums/images/graemlins/tongue.gif I would have just used hoses at that point. Here is a link of a company you could have machine you a part or parts NOT real cheap either /forums/images/graemlins/shocked.gif.

Wait a minute, you have the fittings. Why not get a AN pipe flare and use your existing fittings. That way you could use your fittings and just use a coupling and bend you new lines. You would not have to mess with the crush washers (which no one ever has when they take something apart and re-use the old one /forums/images/graemlins/grin.gif) and you could do what ever you liked in rigid tubing from their out. If I am following your train of thought that is but its late err early...
Anyway good luck