A question about hydraulics?
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Elder User
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From: azle texas
A question about hydraulics?
I'm not sure if I should post this, in this section. I think there is a lot of good information in this part of FTE. I hope I don't get slammed.
I've got a 97 ford chipper truck and it has a pto driven dump bed. The hydraulics are not working properly. Changed the fluid, it called for dextron atf. Thought that might work. It didn't. The pump is pumping, and it gets hot. Bed does not dump.
I've got a 97 ford chipper truck and it has a pto driven dump bed. The hydraulics are not working properly. Changed the fluid, it called for dextron atf. Thought that might work. It didn't. The pump is pumping, and it gets hot. Bed does not dump.
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From: Nutter Fort, WV
I second the intake tube being blocked.
A filter on the return line to the tank is worth it's weight in gold.
I have seen more than one person use heavier oil in a hydraulic system when it is worn so it builds more pressure.
Also if you have a relief valve in the pump/system, it may be stuck open.
When you put the control in hold, does the bed stay up?
If not, the control valve seals may be leaking letting the fluid bypass in the valve instead of going the cylinder.
A filter on the return line to the tank is worth it's weight in gold.
I have seen more than one person use heavier oil in a hydraulic system when it is worn so it builds more pressure.
Also if you have a relief valve in the pump/system, it may be stuck open.
When you put the control in hold, does the bed stay up?
If not, the control valve seals may be leaking letting the fluid bypass in the valve instead of going the cylinder.
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Elder User
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From: azle texas
Thats the kind of info I have been looking for, I will get on it this afternoon. Also i have been told that I need to bleed the air out, I am not sure about that, sounds dangerous.
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Post Fiend
Joined: Nov 2003
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From: Nutter Fort, WV
If it is a single action cylinder, it should self bleed.
It might not go up all the way the first time, but several up/down cycles and it will then make a full stroke.
You will probably have to add more fluid after the first couple cycles unless you tank is rather big.
If the cylinder has an option for power down, there should be a vented plug in the power down port so air can enter and leave the other side of the piston as the bed goes up and down.
If that port gets plugged, it can make them act funny, but it should still go up.
Just be carefull, once the bed starts up, getting under it with any part of your body is like looking down the barrel of a loaded gun with the safety off.
Dump beds probably kill or injure more people every year than gun accidents do.
It might not go up all the way the first time, but several up/down cycles and it will then make a full stroke.
You will probably have to add more fluid after the first couple cycles unless you tank is rather big.
If the cylinder has an option for power down, there should be a vented plug in the power down port so air can enter and leave the other side of the piston as the bed goes up and down.
If that port gets plugged, it can make them act funny, but it should still go up.
Just be carefull, once the bed starts up, getting under it with any part of your body is like looking down the barrel of a loaded gun with the safety off.
Dump beds probably kill or injure more people every year than gun accidents do.
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Post Fiend
Joined: Nov 2003
Posts: 21,285
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From: Nutter Fort, WV
Since I work in the excavation business, I see lots of dump trucks in operation.
As the pumps wear and temp increase, I see many drivers increase the RPM's to compensate for thinner hydraulic fluids as the day goes to hotter temps.
This temp problem is worst if the truck is making a very short haul, no time for the fluid to cool down between dump cycles.
Some are so high, the hydralic pump has to be cavitating, which then causes excess pump wear, making the base problem worse.
The small increase in dump speed is rarely worth the pump damage they are risking by increasing the RPM drastically when they dump the bed.
A valve problem might be responsible for your problem, but I am leaning toward the pump being the cause.
As the pumps wear and temp increase, I see many drivers increase the RPM's to compensate for thinner hydraulic fluids as the day goes to hotter temps.
This temp problem is worst if the truck is making a very short haul, no time for the fluid to cool down between dump cycles.
Some are so high, the hydralic pump has to be cavitating, which then causes excess pump wear, making the base problem worse.
The small increase in dump speed is rarely worth the pump damage they are risking by increasing the RPM drastically when they dump the bed.
A valve problem might be responsible for your problem, but I am leaning toward the pump being the cause.