JD 450 (1968) main hydraulic line repair/replacement

[little1406]

My JD450 has developed a crack in the 1" diameter metal hydraulic line that runs from the pump in front all the way back to the main control valve. The crack is right up front where the 1" tube was bent rather sharply 90 degrees, too sharply I believe as the tube is about halfway crimped there creating an oval cross-section which, of course, flexes as the ~2000 psi comes and goes in that line.

Well, I've got a TIG welder and I'm pretty good at repairing such things so I tried to remove that line today. Whew! After a hell of a struggle with monster wrenches that ended up involving a come-along to pull on one of the wrenches!, I got it loose at both ends but there's just no way that line can be removed from the crawler without taking a lot of other stuff apart. I even removed the 1.5" diameter return line that runs right along with the 1" supply line and still there isn't enuf room to get that thing out. The problem is that the rear end of the line is also bent up 90 degrees and the bent leg is about 5-6" long and there's just no room for that leg to snake out through the frame.

Plus, in view of the failure mode, I don't think a weld would hold for very long. That oval section of the pipe is never going to stop flexing.

So I'm asking the experts here if replacing that metal line with a hose is a workable idea? I'm hoping I could get some factory-made 90 degree elbow fittings for the hose ends that would keep me from having to bend the hose itself real sharply.

Thanks in advance.

[JWB Contracting]

I don't think the steel high pressure line can be removed without pulling the engine.

I have seen many replaced with hydraulic hose. Normally the hose is looped upwards at the front and attached to the pump with a 90 degree swivel end elbow. A good quality hose will not pinch off from the being bent upwards to attach to the hydraulic tank.

[little1406]

Thank you very much, Jason. I agree that something big would have to come apart to get that metal pipe out of there. I'm going to sawzall it into two pieces to remove it.

The loop up in front and over to a 90 into the pump sounds like a plan. I'm working on it now and will report back here on how it works.

BTW, is there any special procedure for getting all the air out of the hydraulic system that I'm introducing with these hose replacements?

[Scottyb]

Scott,
I did the exact same fix on my 350b as you are doing. My pipe had rubbed on the frame until it started leaking. I also had a few welds on it from the previous owner(s) so it was an easy decision to change it out. My return line had a few bad rubs as well so I split some black plastic water hose end to end and slid it over the return. Two hose clamps keep it in place so I assume it will last for a long time yet.

Scott Bartlett

[kedorland]

The gentleman who owned our 75 450C...had a main line failure also. He torched a hole through the top of the hard nose and ran a 1" hydraulic hose from the pump and up across the hood to the valve assy.

One of the issues I haven't straightened out yet. Was considering routing a hose as you described.

Kevin from Iowa.

[little1406]

The hydraulic repair went well! It was not easy to wrestle that 1" hose into position and then get the old return line put back into position but, after about three hours of struggling with it by myself, I succeeded. I filled the reservoir with fluid, fired up the engine, checked for leaks, shut down the engine, filled the reservoir again, fired up the engine and tested things by operating one of the cylinders on the backhoe to its limit, which causes the full pressure to appear on the new 1" hose. Wow, 2000 psi is enuf to cause that 1" hose to flex a bit.

Yeah! no leaks at all, my crimps seemed to hold perfectly and the repair even looks half decent.

Thanks for the help!

[little1406]

Well, I spoke too soon about "no leaks". The front fitting is leaking at the crimp now....! It started out as a seep and after a couple hours of use has developed into a spray. I'm using Weatherhead brand 1" R16 hose and a fitting from discounthydraulichose.com that has a little boxed "K" trademark on it. My crimper is an old T400 Coll-O-Crimp that's seen quite a bit of use. I used the correct top ring (silver) in the correct orientation (flat side up) and obtained a final crimped diameter of 1.515" where the nominal is 1.525" so I thought everything was good.

Does this sort of thing just happen sometimes? Can I recrimp with the top ring inverted so it crimps it considerably farther? Is there any sort of sealer one should apply to the barbs before crimping?

Any assistance would be greatly appreciated....!

[little1406]

I finally got all the stuff together to attempt a fix on that leaking crimp fitting. It was a cluster of equipment (engine welder providing 120VAC to Coll-O-crimp motor, all sitting on the tailgate of my pickup backed right up to the nose of the 450 so I could get the pump end of the new 1" hose into the crimper without removing the hose entirely) but it worked!

I put the leaking crimp fitting back into the 1" collet and crimped it much farther than normal by placing the "drive ring" flat side down onto the crimp dies. That pushed the dies about 0.16" farther into the die bowl than usual. To my mild surprise, the crimp looks great....it's just considerably tighter than before.

But the best news is that, even after a couple of hours of rigorous backhoe operation, the crimp connection is completely "dry".

I don't know why the original crimp leaked. There's a fitting on each end of that hose and the other end does not leak. Oh well, I hope this is an isolated case.

Scott

[Paul Buhler]

Sounds like a good plan well executed. Isn't it nice when an "easier" solution actually works. Congratulations on solving your problem; nice that you had the right tools too. Paul