hydraulic pressure warning

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shaneb

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Jan 20, 2007
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I have a 753 melroe bobcat. the hydraulic pressure warning is going off, it has happend to me before when it had a leak in a hose. When it was replaced the warning went away. I think I have all the leaks fixed finally six hoses later. does anyone know what will cause this alarm.
 

skidsteer.ca

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That means the Hydraulic Charge Pressure is to low. Could be time for new filters, oil is cold (too thick) and can't get through the filter fast enough, or just a pressure sender that is getting tired. There are also a dozen or more places the oil can escape.
When does the light tend to go off, all the time, on cold startup, while lifting and driving??
Ken
 

sterlclan

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That means the Hydraulic Charge Pressure is to low. Could be time for new filters, oil is cold (too thick) and can't get through the filter fast enough, or just a pressure sender that is getting tired. There are also a dozen or more places the oil can escape.
When does the light tend to go off, all the time, on cold startup, while lifting and driving??
Ken
you could start at the port block its on top of the hydralic pump there is a filter on the right side (sitting in the machine)behind the middle hose take the hose off and remove the fitting the filter is in there its bronze and could be cleaned but a new one is cheap enough theese filters often get overlooked and are often clogged to some degree good luck Jeff
 

shaneb

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That means the Hydraulic Charge Pressure is to low. Could be time for new filters, oil is cold (too thick) and can't get through the filter fast enough, or just a pressure sender that is getting tired. There are also a dozen or more places the oil can escape.
When does the light tend to go off, all the time, on cold startup, while lifting and driving??
Ken
The alarm has gone off before when i was lifting but it was because i had a leak in a hose. this time it's when driving no w/ no load maybe at 1/3 throtle
 

Tazza

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The alarm has gone off before when i was lifting but it was because i had a leak in a hose. this time it's when driving no w/ no load maybe at 1/3 throtle
That could be the problem, you need to drive at near full throttle.
 

skidsteer.ca

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The alarm has gone off before when i was lifting but it was because i had a leak in a hose. this time it's when driving no w/ no load maybe at 1/3 throtle
The best would be to install a pressure guage in the sender port and observe your charge pressure. It will fluctuate quite a bit. Lowest readings will be when you bottom a cylinder on the extend stroke, or nearly stall the the engine with the drives.
Just cruising along like you mention the reading should be fairly stable
Not sure on yours, I believe my 553 was @ 100psi. warning at 25??
It jumped around alot between 60 and 100 depending on what the operator was doing.
Would flicker momentarily if you bottomed out a cylinder.
Could be as simple as a worn through wire getting a ground that turns the light on, or bad sender, or many hyd issues.
Does the machine seem to operate fine? or can you feel it “lay down” when the light comes on?
Ken
 

skidsteer.ca

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The best would be to install a pressure guage in the sender port and observe your charge pressure. It will fluctuate quite a bit. Lowest readings will be when you bottom a cylinder on the extend stroke, or nearly stall the the engine with the drives.
Just cruising along like you mention the reading should be fairly stable
Not sure on yours, I believe my 553 was @ 100psi. warning at 25??
It jumped around alot between 60 and 100 depending on what the operator was doing.
Would flicker momentarily if you bottomed out a cylinder.
Could be as simple as a worn through wire getting a ground that turns the light on, or bad sender, or many hyd issues.
Does the machine seem to operate fine? or can you feel it “lay down” when the light comes on?
Ken
Oh yes, that rpm is vary low to operate at, unless it is vary easy going
 
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