control valve or pump?

[elbowcarey]

Hey guys I have another ? 543 with slow hydralics, everything works just slower then it should be and the light comes on and off. So I checked and the control valve seems to be leaking so I ordered a seal kit to rebuild since it was only $100. I have not run it hard or for more then a few minutes since I bought it and replaced the left side drive. The pump has never been hot to the touch after running it and no leaks on the pump itself. I must have low charge pressure but how do I know what to work on first to fix this problem, I picked the rebuild kit because it was cheap and its leaking anyway. Also I seen in the manual that you can adjust the relief valve clockwise to increase pressure is this a good idea to try or will it just make it out of adjustment once I rebuild the control unit? Any help would be great

 

[donald73d]

In some Bobcats the lights comes on for clogged filter (in the engine bay) in addition to other problems in the hydraulic system. Have the hydraulic filter(s) been changed recently?

 

[elbowcarey]

In some Bobcats the lights comes on for clogged filter (in the engine bay) in addition to other problems in the hydraulic system. Have the hydraulic filter(s) been changed recently?

Yes. I just changed it when I replaced the left side drive. I think it has an issue because before I changed the filter the hydralics were slow too.

 

[Fishfiles]

Yes. I just changed it when I replaced the left side drive. I think it has an issue because before I changed the filter the hydralics were slow too.

pressure equals power , flow equals speeds , so adjusting a relief cartraige , which increases the pressure , is not going to make it any faster , and after resealing the controll valve you don't have to adjust anything , 99.9% of the time you don't need a complete kit to stop a controll valve leak , spool seals , reubber boots and a couple of orings for $15 is all you need , and unless it is leaking 5 gallons per minute it is not going to slow down the functions --------------- make sure the drive belt is tight , if that don't help , then do a flow test of the hydraulics at the quick couplers on front the machine , this will only test the boom , tilt and aux ,don't have a book in front of me but would guess 15 gallon per minute give or take would be close to what you should have , if the travel is slow also , then that is another story

 

[elbowcarey]

pressure equals power , flow equals speeds , so adjusting a relief cartraige , which increases the pressure , is not going to make it any faster , and after resealing the controll valve you don't have to adjust anything , 99.9% of the time you don't need a complete kit to stop a controll valve leak , spool seals , reubber boots and a couple of orings for $15 is all you need , and unless it is leaking 5 gallons per minute it is not going to slow down the functions --------------- make sure the drive belt is tight , if that don't help , then do a flow test of the hydraulics at the quick couplers on front the machine , this will only test the boom , tilt and aux ,don't have a book in front of me but would guess 15 gallon per minute give or take would be close to what you should have , if the travel is slow also , then that is another story

Well yes the belt was loose a bit so I tightened that and also noticed the throttle wasn't staying all of the way up when in full throttle so I fixed that to.... But no different as to the slow hydraulics. It doesn't seem to drive slow though, I would say that it is more in the bucket and tilt, The book says it is suppose to to lift to full mast in 4.5secs and it takes like 9, and full bucket movement the same. I do not have a hydraulic test kit to measure the flow as of now. I ran the machine for approx 15 mins and it seems to run fine just slower, also I felt the pump and it was hot but its going to be from use. Also I was reading a different thread and someone said that the hour meter and hydra light are wired together, my hour meter doesn't work so maybe the sensor is shot? I measured 12v/~ off of it however there are two terminals on it, and then another wire that comes off of it which is disconnected, where is this one suppose to go? I am assuming on the port block because I seem that there is a temp sensor on it but I'm not sure? I did hook it up there but no difference with the dash light still in/out when machine is in use.

 

[Tazza]

Well yes the belt was loose a bit so I tightened that and also noticed the throttle wasn't staying all of the way up when in full throttle so I fixed that to.... But no different as to the slow hydraulics. It doesn't seem to drive slow though, I would say that it is more in the bucket and tilt, The book says it is suppose to to lift to full mast in 4.5secs and it takes like 9, and full bucket movement the same. I do not have a hydraulic test kit to measure the flow as of now. I ran the machine for approx 15 mins and it seems to run fine just slower, also I felt the pump and it was hot but its going to be from use. Also I was reading a different thread and someone said that the hour meter and hydra light are wired together, my hour meter doesn't work so maybe the sensor is shot? I measured 12v/~ off of it however there are two terminals on it, and then another wire that comes off of it which is disconnected, where is this one suppose to go? I am assuming on the port block because I seem that there is a temp sensor on it but I'm not sure? I did hook it up there but no difference with the dash light still in/out when machine is in use.

It does sound like the pump is weak. My dad has a 453 that has really slow hydraulics, the drive is really fast, but lift and tilt are very slow. I need to get a new pump for it.
To know for sure you will need to get it flow tested. They need to put a restrictor in series to load it to about 2,000 PSI and measure the flow, so its not as easy as pump out X amount in y time to work out the flow.
Yeah, if the sender is not working right, the hour meter will not function. Not sure exactly where that wire goes, but if you ground it, does the hour meter work?

 

[elbowcarey]

It does sound like the pump is weak. My dad has a 453 that has really slow hydraulics, the drive is really fast, but lift and tilt are very slow. I need to get a new pump for it.
To know for sure you will need to get it flow tested. They need to put a restrictor in series to load it to about 2,000 PSI and measure the flow, so its not as easy as pump out X amount in y time to work out the flow.
Yeah, if the sender is not working right, the hour meter will not function. Not sure exactly where that wire goes, but if you ground it, does the hour meter work?

Thanks
I will have to get it flow tested, I see what you are saying............It needs to have load on it to see if there is any leakage..........Is there a way I can do this? What do I need ? I would rather do the testing myself and own the equip. then pay someone else just to test to tell me something..............If I ground it No it does not work ..... Thx Tazza

 

[Tazza]

Thanks
I will have to get it flow tested, I see what you are saying............It needs to have load on it to see if there is any leakage..........Is there a way I can do this? What do I need ? I would rather do the testing myself and own the equip. then pay someone else just to test to tell me something..............If I ground it No it does not work ..... Thx Tazza

You could do it your self, but do this at your own risk! Hydraulics under pressure are dangerous.
You will need specs on your pump, how many GPM it should provide at X pressure.
Get a gauge and hose, both will need to be rated for at least 3,000 PSI. You will need some sort of restrictor valve to put a load on the system. I have some hydraulic ball valves that work for this. Install the hose and gauge to the pump, then the restricting valve. Fill the hydraulic tank and start the machine with the valve open. You need to screw it down SLOWLY to get the pressure you are after. There is no relief from the pump to the valve, so if you close it off, it will probably burst the hose or gauge and hurt you. Be warned.
When the system is loaded down like this, you can direst the oil into a bucket for a set time. Calculate the amount of fluid you got in what time and work out how many GPM you are getting. The correct way to do this is to get the system warm first, so the oil is thin. This will give you a more acurate reading.
Again, do this at your own risk. The correct testing gear does this in series with the pump, so its not messy, this way will be messy and potentially not as safe. Be careful if you go this way.