T300 Hydraulic charge pressure low?

[Richard57]

Let me try this again, What are some of the causes of, Hydraulic charge pressure low, code 05-09? I have a T300 with SJC controls. Any help would be appreciated.

 

[River Fluid Power]

Let me try this again, What are some of the causes of, Hydraulic charge pressure low, code 05-09? I have a T300 with SJC controls. Any help would be appreciated.

You could be looking at any of several problems, some of which I am sure I can't think of.

1. damage to charge pump, possibly caused by contamination
2. damage to loop, either in a pump or motor (valve plate, barrel, piston slippers), generally caused by contamination
3. damaged servo seals
4. debris in charge relief valve

 

[River Fluid Power]

Normal wear can eventually lead to low charge pressure as well. This could be the case on high a machine with high hours.

 

[polishpete]

CJECK YOURE BELT THAT AND SWITCH COULD BE BAD HAPPEN TO ME

 

[polishpete]

IF BELT IS GOOD ONLY REAL WAY ID WITH A GUAGE

 

[Richard57]

IF BELT IS GOOD ONLY REAL WAY ID WITH A GUAGE

I have gauges hooked up

 

[Richard57]

Normal wear can eventually lead to low charge pressure as well. This could be the case on high a machine with high hours.

2800 hours

 

[Richard57]

You could be looking at any of several problems, some of which I am sure I can't think of.

1. damage to charge pump, possibly caused by contamination
2. damage to loop, either in a pump or motor (valve plate, barrel, piston slippers), generally caused by contamination
3. damaged servo seals
4. debris in charge relief valve

How would I check for debris in charge relieve valve?

 

[Richard57]

CJECK YOURE BELT THAT AND SWITCH COULD BE BAD HAPPEN TO ME

Where is this switch?

 

[polishpete]

WELL THEIR IS TWO THINGS U COULD DO CHECK THE HYDRO SWITCH PRESSURE
AND U COULD SHIM THE VALVE TO GET MORE PRESSUURE THATS WHAT I DID

 

[polishpete]

WHATS YOUR PRESSURE READING IN HIGH IDLE

 

[thoughtbelt923]

How would I check for debris in charge relieve valve?

One good way to find the location of all this stuff is to go on partscatalog.bobcat.com, enter your serial number, then look for the part. You'll get an exploded diagram.
The charge relief on a manual control machine is on the backside of the left hydrostat. I took a quick glance at an sjc diagram just now and it looks to be in a similar position. It's a nut, adjuster, spring, and poppet. The manual controls have shims to adjust charge pressure, it looks like sjc has it all in the adjuster part. The spring could be broken/damaged, have something lodged in it, or the poppet could be damaged.

I couldn't find the pressure sender quickly, but it should be on there as well. It is either on the control valve coming off of a tee with one line coming from the hydrostat or on the hydro filter assembly.

For contamination, replace your hydraulic filter and open up the old one. Check for debris, what kind of metal, and how much. Also check your case drain filter(s) for metal. You could also drain your reservoir and take a look inside there. Brass generally means hydrostat, but I think it could mean motors too and the gear pump also has some brass colored gaskets that can get chewed up. Steel could be from any hydraulic part as far as I understand it.

To do a cursory check of your motor brake seals, you can take note of charge pressure at high idle and then at high idle after disengaging your brakes/hitting the green means go button. If it drops significantly and stays dropped, you likely have significant case drain leakage which means your motor/motors need resealed. You can also do a case drain test, take one side of the case drain while leaving the other connected. Put the hose in a bucket, take note of how much fluid is coming through at idle with and without the brakes engaged. Then do the other side. If the fluid is flowing pretty good, then that also points to leaking motors.

 

[Richard57]

One good way to find the location of all this stuff is to go on partscatalog.bobcat.com, enter your serial number, then look for the part. You'll get an exploded diagram.
The charge relief on a manual control machine is on the backside of the left hydrostat. I took a quick glance at an sjc diagram just now and it looks to be in a similar position. It's a nut, adjuster, spring, and poppet. The manual controls have shims to adjust charge pressure, it looks like sjc has it all in the adjuster part. The spring could be broken/damaged, have something lodged in it, or the poppet could be damaged.

I couldn't find the pressure sender quickly, but it should be on there as well. It is either on the control valve coming off of a tee with one line coming from the hydrostat or on the hydro filter assembly.

For contamination, replace your hydraulic filter and open up the old one. Check for debris, what kind of metal, and how much. Also check your case drain filter(s) for metal. You could also drain your reservoir and take a look inside there. Brass generally means hydrostat, but I think it could mean motors too and the gear pump also has some brass colored gaskets that can get chewed up. Steel could be from any hydraulic part as far as I understand it.

To do a cursory check of your motor brake seals, you can take note of charge pressure at high idle and then at high idle after disengaging your brakes/hitting the green means go button. If it drops significantly and stays dropped, you likely have significant case drain leakage which means your motor/motors need resealed. You can also do a case drain test, take one side of the case drain while leaving the other connected. Put the hose in a bucket, take note of how much fluid is coming through at idle with and without the brakes engaged. Then do the other side. If the fluid is flowing pretty good, then that also points to leaking motors.


View attachment 4904

Thanks for the info , I'll keep looking.

 

[polishpete]

SEE WHERE 70 IS IF U ADD A SHIM TO IT IT WILL WORK

 

[Richard57]

CJECK YOURE BELT THAT AND SWITCH COULD BE BAD HAPPEN TO ME

So I'm thinking that if code only comes on at low idle and seems to go away in high idle , maybe worn out belt even though it looks good.

 

[polishpete]

COULD BE