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Adding hydraulic lines for detach trailer


Deere Mack

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Check the air solenoid on the pump. Sometimes after they've sat for a while, they don't want to move. If it is seized up, it doesn't matter where the cab switch is, the pump thinks it is supposed to "hold"...meaning no pressure in the line. Also, the controller should turn the PTO off when you move it to the "lower" position to prevent pump damage.

When approaching a 4-way stop, the vehicle with the biggest tires has the right of way!
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Also, the controller should turn the PTO off when you move it to the "lower" position to prevent pump damage.

That may be true but I've never seen one hooked up that way. Not a bad idea though as I've seen pumps burnt up from being left on while the truck goes down the road.

When you engage the PTO, does the engine load up at all? If the coupler is bad, the relief on the pump should open and it will load up the engine when this happens.

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It isn't how it is hooked up, but rather the controller itself. The air operated switch in my cab, I engage the pump with the switch still in the "hold" position, then move the switch to "raise" to put pressure in the line. I can go back to "hold" if I need to pause for a moment and back to "raise" as often or as many times as I need to, but as soon as I hit "lower", the PTO disengages from the pump so the pump isn't damaged when the fluid is flowing back to the tank. Figured that was pretty standard.

When approaching a 4-way stop, the vehicle with the biggest tires has the right of way!
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It isn't how it is hooked up, but rather the controller itself. The air operated switch in my cab, I engage the pump with the switch still in the "hold" position, then move the switch to "raise" to put pressure in the line. I can go back to "hold" if I need to pause for a moment and back to "raise" as often or as many times as I need to, but as soon as I hit "lower", the PTO disengages from the pump so the pump isn't damaged when the fluid is flowing back to the tank. Figured that was pretty standard.

I'll admit I haven't seen too many that the valve worked off air but I've never seen one work that way. Not saying they don't, I just haven't seen one.

Any pump setups I've seen, the fluid doesn't run back through the pump when in the lower position. It goes through the valve and back to the tank.

Now if your check valve isn't working or you have a pump setup without a check valve, if you depress the clutch with a raised bed and lever in the raise position, the oil will turn the pump backwards and the bed will fall.

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Spool valve seems to be working. I'm a little suspicious of the 1inch wing type coulpler. I cleaned up the old one before attaching the male side and new hose I had made. It started raining again so I didn't pull it. Is it possible the old female side of the coupler is stuck?

I also had that problem with the wing nut connection. I unhooked the connection and engaged the pump and pushed in on the female side and had hyd fluid spray out so I new it was the connection. Just an idea
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  • 2 weeks later...

Well, the bad luck continues. Today was the first day I tried to use the trailer loaded. It works fine unloaded, it will raise and lower as it should. But with a load on it, it will not lift. It's like something is sticking open, engine doesn't load , it just stalls out and will not lift. Any ideas?

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You can usually get a replacement as cheap as you can rebuild. They aren't hard to rebuild though, if you can find the parts.

As has bee said, put a pressure gauge on it. If you don't have proper pressure, check the relief valve first. With the pressure gauge, if the pump is worn the pressure will increase with engine rpm. If it's a relief problem, whatever pressure you have at idle, it shouldn't increase with rpm. Most pumps should be putting out at least 2,000 psi and should be capable of being turned up at least 2,500 psi.

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I haven't put a gauge on it, but it's obviously losing pressure at a certain point which makes me think its the relief valve. What should I expect if I pull the relief valve to inspect, anything going to fly out? Also I did find this doc on the muncie website. Since I did cut and weld on the supply tank the relief valve could be contaminated. Thought I got it all out but maybe not.

Also, will the pump allow me to add a filter or screen on the supply line to remove any other contaminants?

post-5458-0-78041400-1454766204_thumb.jp

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as rowdy said it may starve the pump. i had to take my filter off cause when its cold the pump was super slow. if all you do is run your own stuff off the hyd. system and dont run a 100 different trailers you should be fine

We the unwilling, Lead by the unqualified, are doing the impossible, for the ungrateful.

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The spring and ball can fly out when disassembling the relief, just be ready to catch it. Most are adjustable but some aren't. On the ones that aren't, sometimes you can put a spacer behind the spring to increase pressure (usually a dime or washer will work).

If you are going to run a filter, put it on the return to the tank. None of our trucks have filters.

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