I just bought a JD-400 with a Johnson 20 front loader and Brantly LD-6 backhoe.:tango_face_grin:
I worked a deal with my neighbor who has the equipment to make hydraulic lines. Now I have to figure out what fittings and hoses are needed to build them. It appears there are only two or three fitting types with hoses of different diameter for attachment hydraulic pistons. Is there somewhere I can find this information? Most of the fittings are pretty corroded so it's going to be hard to ID any markings. I'm assuming they are standard industry hardware.
The work hoses should be 1/4" rated for 1900-2500 psi with -6 JIC 37° female terminations. Adapter fittings for the valve and cylinder ports should have the matching -6 JIC male end to mate to the hose and the correct thread and size to fit the port.
The "-6" is the size, nominally 3/8", which is preferred for strength in this application, even on the 1/4" hoses. Going with larger nominal size fittings than necessary for an application is acceptable practice. Going smaller is not.
Changing out all the lines and fittings on a loader and hoe is not a cheap proposition. It will chew a sizable hole in a $1000 bill. The outer rubber covering on hoses is for abrasion protection. Cracks in it don't hurt the function of the hose. Broken wires in the braiding underneath that covering are a good reason to replace the hose. Otherwise, if they aren't leaking, I'd leave them alone.
Thanks for the detailed info Tudor. Yup, I don't want to whack my wallet all at once, but also don't want a failure after installing the new pump and working the tractor. There's a group of hoses which obviously need immediate replacement.
The backhoe third hose from the left is larger with a different fitting, but the others seem to be the same.
The tractor came with a new hydraulic pump which the owner intended to install before deciding to sell. I looked up the numbers and found it to be a Dynamic 0.66 cu in GPF1018PC. It came with several parts for adapting the PTO to it, which I will have to figure out. Photo attached of the two primary pieces. The front loader and backhoe work very slowly, due to the undersized pump and this one is to bring it up to normal operation.
Here's the other parts which came with the pump. The two shaft pieces fit in each side of the chain drive as a step-down adapter. Not sure how all that plugs and plays until removing the old pump.
Yup. Some of those hoses have seen better days. The one 3rd from the left appears to have the same fitting. I suspect that that hose has been change at some point to a hose with 2 wire braids, hence the extra thickness.
You will find that the new pump will flow too much for control. It also flows too much for 1/4" hoses. A 0.40 cu-in pump flows at the upper limit for 1/4" hose.
I'm assuming the other apparatus will work with the smaller pump as it's the same envelope. Will have to try and sell this pump to offset the cost of another one. Oh well, this is why I check everything with knowledgeable folks.
Hmm. That's the right size hoses for the pump that you have.
Do you know the relief pressure for the system? What are the cylinder sizes?
The reason that I ask is that the factory hoe on my SCUT uses 1/4" hoses with a max pressure of 2000 psi and a max pump flow of 6.1 gpm for a 2.5x16.75" boom cylinder, and it is a rough ride trying to control the hydraulics at WOT. I usually run at 1/2-2/3 throttle until I'm in the groove.
To make use of that pump for your tractor, the pressure would have to be considerably lower (that's reasonable with the lighter tractor) and the cylinders would have to have considerably more volume to keep the speed down. Larger volume equates to better leverage and even less required pressure.
It's one thing to operate a hoe all day, every day, at speed. It's a whole different prospect to operate at speed if you only use it for a couple of hours every few months. In ten years, I've used my hoe for about 30-40 hours. A couple of times for jobs lasting several hours, but mostly for jobs that took from 10 minutes to maybe an hour. Basically, it's retraining day every time I use it and speed is not what you want when reaclimatising to hydraulic controls that operate something that is strong enough to put a serious dent in the wall of a house.
Since the same pump usually operates the loader, and the loader lift cylinders are probably 2x18", the resulting speed will be subject to over controlling at much above idle if there are no flow restrictors in place. Flow restrictors add heat to the system, and too much heat kills hydraulics.
Figured out the loader/backhoe I was looking at is the wrong one. Those are for a 'Tractor' with 1/2" hoses, where I have the 400 Hydrostatic and is the ONLY listing for it. However, the correct listing below does not show the backhoe or loader as implement options. Yet, on my original thread a member posted a document showing both as options for the 400. It's very confusing. I'm trying to get an IPL for the loader/backhoe so I can ID the hose fittings and lengths. I think I'll just have to do it the old fashioned way and measure them.
1475 - 400 Hydrostatic Tractor - 10Jul08
Implement
1079 - 54 and 56 Front Blades
1476 - 60-Inch Tractor-Mounted Mower
1531 - 35 and 35A Tractor-Mounted Tillers
The only cylinders not original are the two for loader tilt on upper arm (red). He replaced them with oversized and fabricated new attachment brackets to clear the arm.
You are correct I have 1/4" hoses and my neighbor concurs. Now back to square one and the original question to you: Which Dynamics pump would you recommend for this setup? (see the link on previous post)
On a 400, the front or mid mount pto is only about 2000 rpm at full engine speed. At 1/2 - 2/3 engine speed I would think a .66 cu in pump would work, since it is not turning at engine speed.
One less thing to worry about! I can go ahead and install the pump while the lines are disabled. What a relief! Also have the rebuild kit for the steering control valve, which is glitchy.
I'm going to be using the 318 and 400 fairly often for most of the summer. I inherited this place from my parents about 4 years ago; moving in from Phoenix Arizona 3 years ago after retiring. It's been neglected for some years. I am landscaping & reshaping the property to sell, hopefully, sometime next year. I will be creating drainage channels and a holding pond for water runoff. Also digging up the septic system and possibly part of the drain field for repair. Expanding the gravel drive to form a loop with new gravel on all. Some or most of the yard will need to be turned and grass replanted, which is why I bought the 318 with a blade and tiller. The tractors will be getting a workout so I want them in reasonable shape so I don't have to keep stopping for repairs. The 400 is in the 'worse' shape, but all there and functioning. I didn't realize what a find it was until posting this forum.
Bob - I really appreciate the time and input you've provided. I'm on a couple forums for BMW Airhead motorcycles (1969-1996) for 20+ years, but this is the first and only tractor forum. So far, the info has been great for a newbie. I'm not new to mechanics and have a pretty good shop with tools accumulated over many years. Hydraulics is a new world for me and the spool-up time is greatly reduced by folks like you. Thanks!
I started making and selling custom parts for Airheads 20+ years ago for club members as a hobby. The last 5 years I ramped it up to more of a business in anticipation of retirement. It's doing better than expected and now investing in designing new products.
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