I'm having some issues with my 320B excavator and here are the symptoms: Little or no response on all hydraulic functions. Lots of flow through the suction line from the tank to the pumps. Little or no engine lugging or power loss when hydraulics are used. This problem started to gradually get worse in about a half hour period before not working at all. Changed all filters and strainers with no results. help. please. Thanks
It might be a problem with the PRV that supplies Powershift pressure to the pumps. Also machines with many attachments feed pilot pressure into the Negative Flow Control ports to cut back pump flow, a problem with that circuit if used could do that. Sounds like a control problem rather than a big failure. Need to put a couple of gauges on the pumps. Later Bob
This machine only has the thumb for attachments. (also a bucket
Good day Leewald Suggest you start at the beginning check the pilot pressure this could cause the issue you describe. If we can help check out excatech.com Kind regards Uffex
I got from another source that because it performs somewhat better whn its cold (the oil) the pump is faulty. We changed the pump and it still got us the same results. Expensive way to rule potential problems out, I know. The PRV also seems fine. Pilot pressures good too. Anymore suggestions?
Do you have a service manual? I seems the cost of a book would have been far less of a risk than just changing a pump.
Yeah we do, but I can't seem to find anything illustrating the problem we're experiencing. Which is why I came to this forum.
The first thing you need to do is check pilot pressure (as said earlier)at the pilot manifold located just under the main hyd pump . Should see 595 psi . A serial number would help too
I connected my gauge to the pilot manifold and got just under 1000 psi. serial number: 9KK00146
Before you do anything when troubleshooting these machines you need to go into the electronics package and record all active and logged codes. All the Cat B series excavators used the same method to access codes. In this case you hold down three buttons at the same time till the monitor goes into access mode. Then you use certain bottoms to go to each mode. Your book should explain how all that is done. This is easy to do, doesn't cost any money in parts and will confirm that your electrical and electronic system is or isn't the problem.
Hi leewaki may be the problem is in the proporcional valve this valve regulate the flow and the pressure of the pumps see in your manual how to disconect this valve and do a test of it
OK so there is problem #1. Thats is almost double what it should be, see if you can adjust that down to 550-600 psi So out of curiosity "Lots of flow through the suction line from the tank to the pumps." how you did test this or come to this conclusion ?
That is too high. Sounds like a problem in the pilot relief valve. It is the screw with a jamb nut next to where you took the pilot pressure. You will need to back it out. What range of gauge are you using ?
I'll try making that adjustment, and also checking errors on the display. Stuck a hand into the Hyd oil reservoir and there was plenty oil moving, so how many GPM the pumps moving I'm not exactly sure tho. Range of the gauge is 0-10000. Not exactly ideal if you want to set something at 500 psi.
With a 10000 psi gauge you may really only have 600 psi. You should try a 1000 or 3500 psi gauge instead.
I put pressure fittings on the 2 pumps (top and bottom) and they both gave me approx. 250 psi, should be close to 2000 right? <<I failed to mention this earlier, thought I had said it somewhere. sorry bout that. Thanks.
What are you testing here. The pumps should be as high as 4550 psi when you stall a function.
Pls send me your e-mail address. I can help you.
Just the pressure pumps put out, no load, at 1800 RPM.
I am one of the guys working on the 320l with no hy functions working. Charge pump pressure 550 psi new PRV . We put in a flow meter in the top line pump is putting out flow and pressure but when we try a function there is no response where can the oil bypass so that there is no response . We thought that maybe the controls were not getting enough pressure checked pressure with a inline t and were getting 550 psi so we thought maybe spool is stuck so we manually pressed down on spool still no response that was with line plugged and function in cab used so that charge pressure was at pump . We are not getting a pressure reading on the pressure side of pump with flow meter removed so our question is where can the oil bypass other then the relieve valve
I am one of the guys working on the 320l with no hy functions working. Charge pump pressure 550 psi new PRV . We put in a flow meter in the top line pump is putting out flow and pressure but when we try a function there is no response where can the oil bypass so that there is no response . We thought that maybe the controls were not getting enough pressure checked pressure with a inline t and were getting 550 psi so we thought maybe spool is stuck so we manually pressed down on spool still no response that was with line plugged and function in cab used so that charge pressure was at pump . We are not getting a pressure reading on the pressure side of pump with flow meter removed so our question is where can the oil bypass other then the relieve valve if some can help thanks .
So far your testing is a little vague but the main relief could be stuck open causing a problem. If you leave the flow meter in when you move the main spool does the flow drop or stay the same. Make sure you are checking the proper pump for the valve you are moving. If you have a proper flow meter you should be able to test each pump for flow and pressure.
Flow testing those pumps and adjusting them properly is a bit more involved than what you are doing. You need to get some Oring face TEE fittings that will accept a test nipple for a gauge. It needs to be placed in the NFC lines at the pump. 0 to 1000 Psi should do. Watch the pressure on the gauge as you work a circuit. The pressures should fall to about 100 as the circuit is pulled in full. If it doesn't drop the pumps will not open up from minimum to full angle. Come on back with results. Later Bob
on bottom of control block there are 2 check valves both had the orig blow-en out replaced with new o ring now we have a little hy function but are wandering where the o ring pieces went to could they have blocked off a line inside valve
Which check valves did you reseal?
This is about the 320l with no Hy power took flow and pressure reading at outlet of pump on low speed35 gal flow 3400 psi with flow meter of no pressure at test ports and no Hy movement on anything just a little movement on swing was told it could be pilot operated relieve valve found a friend that had a 320 hoe swooped relieve valve in his hoe with ours , ours did not work in his so we got a relieve valve put it in ours and now it works Thanks everybody for your help