773 - ??? - hyd charge pressure extremely low

[greensideup]

hello. i'm having trouble with a 773 i just bought. i have a 500,000 limited edition model. machine only has about 275 hours. when i start the machine, a get an alarm and the message HYD CHARGE PRESSURE EXTREMELY LOW. then, the machine shuts down. i have to start it between 2 and 10 more times. then, you can hear what sounds like a pump kicking in - and i get pressure. until i get pressure, you cannot lift bucket or more machine. once running, every so often is seems like the hydrolics are binding - then it clears up in a couple of seconds. looking at the sight glass, the hydro fluid level looks good - maybe a little higher than 1/2 up glass. what do i do? where do i go from here? i just bought this machine, and only put about 100 hours on it. thanx in advance for any help with this.

 

[mllud]

If your suction hose going from your Hydraulic tank to your pump is loose it can suck air .That could cause it to lose prime and get air into the system.With low hours It should'nt be mechanical. Look and see if your hydraulic oil is foamy. that would indicate air in the system.
This is just a guess and something to look at.Im sure the Bobcat mechanics will be on soon. Mike

 

[greensideup]

If your suction hose going from your Hydraulic tank to your pump is loose it can suck air .That could cause it to lose prime and get air into the system.With low hours It should'nt be mechanical. Look and see if your hydraulic oil is foamy. that would indicate air in the system.
This is just a guess and something to look at.Im sure the Bobcat mechanics will be on soon. Mike

Mike - thanx - i will check the lines to see if i can find an obvious leak. mus have gotten worse - now the machine would not stay running (build pressure) after 15 or so attempts. i'm at a real roadblock. machine used to stay running after a few attempts. now, seems like pump does not start running to build up pressure . ???????????? thanx, johnny

 

[mllud]

Mike - thanx - i will check the lines to see if i can find an obvious leak. mus have gotten worse - now the machine would not stay running (build pressure) after 15 or so attempts. i'm at a real roadblock. machine used to stay running after a few attempts. now, seems like pump does not start running to build up pressure . ???????????? thanx, johnny

Jonny; My earliar suggestion really should not keep your charge pump from having oil there to pick up and go. The gravity pressure from your tank should keep oil supplied until you start the loader. A loose line on the suction side of the pump could allow air to be drawn into the system. I had problem due to a loose clamp at the tank on my N/H.
I dont know if your pumps are direct drive or belt driven. If belt driven it could be a drive problem. I own a New Holland. You really nne one of these Bobcat guys to help. Mike

 

[skidsteer.ca]

Jonny; My earliar suggestion really should not keep your charge pump from having oil there to pick up and go. The gravity pressure from your tank should keep oil supplied until you start the loader. A loose line on the suction side of the pump could allow air to be drawn into the system. I had problem due to a loose clamp at the tank on my N/H.
I dont know if your pumps are direct drive or belt driven. If belt driven it could be a drive problem. I own a New Holland. You really nne one of these Bobcat guys to help. Mike

Tank is below the pump so it could be a suction line problem.
It could also be a problem with the a small valve that holds a restriction on the oil returning from the main hydraulic system. This restriction maintains your charge pressure. Failing a leaky suction line I'd start there. Tazza just replaced one of these because it was making a odd sound. But if it sticks open you would have no charge pressure. Does your loader boom (foot pedals) function while the no charge pressure light is on?
I believe the charge pressure should only affect the wheel from driving.
Ken

 

[sterlclan]

Tank is below the pump so it could be a suction line problem.
It could also be a problem with the a small valve that holds a restriction on the oil returning from the main hydraulic system. This restriction maintains your charge pressure. Failing a leaky suction line I'd start there. Tazza just replaced one of these because it was making a odd sound. But if it sticks open you would have no charge pressure. Does your loader boom (foot pedals) function while the no charge pressure light is on?
I believe the charge pressure should only affect the wheel from driving.
Ken

check the drive belts on the pump........

 

[greensideup]

check the drive belts on the pump........

thanx all - dumb operator error !! yes, drive belt was loose. simple as it was - took a buddy of mine stopping over - looking at the obvious. thanx for your help - johnny

 

[skidsteer.ca]

thanx all - dumb operator error !! yes, drive belt was loose. simple as it was - took a buddy of mine stopping over - looking at the obvious. thanx for your help - johnny

There is a note to all of us (except Sterclan) don't forget the obvious. Once I read his post I was ready to put my money down. I knew that too, but spaced it out...
Ken