Hello all, I have a 315 BL serial 3AW02248 that's having some issues. All of a sudden the swing and one track started moving slow. So far I have been able to get it to track straight if the bucket is curled until relief. If tracking without the bucket at relief one track barely moves, but if you start to swing the swing speeds up to normal operation. Swapping lines on the valve body for the track motors made the problem switch sides. Using the two switches behind the armrest to bypass the controller also made no difference. The shutdown is now a push button as opposed to the key and has been that way for years, also 3 lights stay on at the bottom of the gauge. They appear to be hydraulic level, oil pressure, and temp. Besides hydraulic oil being milky it runs smooth and has power on all other functions. The operator did not know if those lights came on at the same time as the hydraulic issues.
The three red lights on the bottom indicate in order from left to right: hydraulic oil level is low, engine oil level is low, and engine coolant level is low. I would quickly verify you have correct levels every startup by physically looking at dipsticks and levels, otherwise, you risk destroying your machine. From experience on my 325BL, the electrical lines to these sensors fail over time and need to be repaired. A sensor will fail too but the electrical lines fail from the insulation chafing or becoming brittle from age, heat, and sunlight. The little triangle on the left side of the light usually means the light is about a fluid level. If it was a temperature issue, there is usually a thermometer icon. At least this is how it is for my 325BL. You really need to get an owners manual which helps with understanding what's going on. Attached is the section regarding the gauges and lights. I can't help with the reasons why you're hydraulics are acting up but I do recommend changing out the milky hydraulic oil to clean oil to prevent more potential damage that will likely scrap the machine.
I've been told the oil has been changed several times with no change in milkyness. It seems like it's a wiring issue because all levels are good. It seems to be a load sensing pump or something close to it as the two affected circuits are right next to each other in the valve body and bringing other functions to relief will make them work.
On my B machines, when the hydraulic tank level sensor went south (usually broken @ the epoxy), all 3 lights would stay illuminated. Probably changed ten over the years. You can jumper the tank level sensor (or meter it) to test. Them 3 lights do not affect operation in any way.
The wires for my hydraulic tank fluid level sensor also broke at the epoxy. Must be from shaking/wiggling as the harness was not attached to the hanger and was just flopping around. I remember I took pics of it and finally found them. I also remember testing the circuit with a paperclip to ensure the warning light would go off. It's been a while but I believe by shorting the harness, the system believes the hydraulic tank is full so a broken wire appears as low which is good. Failing to "full" is not good. Note this only affected my hydraulic level indicator as the engine oil level light was a separate issue. But there are three options to fix this so the light doesn't appear on your gauge panel. In order of best to worst: 1) Replace the sensor and secure the harness so it doesn't move and fail again. 2) Keep the paperclip in the harness and check your hydraulic fluid level before and after every time using the machine. 3) Put a piece of black electrical tape over the warning light and only care when your hydraulics start acting funny. Again, my apologies for not helping with your real problems of swing issues.
Thanks for the info on the lights, I wouldntve thought the hyd tank sensor could mess with all 3 warning lights.
I think all the sensors are separate wirings so not sure how one would affect the other but it sounds like it did for @heymccall
I wouldn't have thought that either. 322bl, 330bl, and 345bl were all like that.
From what I've read in the manual they use 2 load sensing pumps, one controls swing and tracks one controls boom, stick, and bucket. Makes sense why my issues are on one circuit. Both pumps have "negative flow control pressure" ports so I suppose swapping those would tell me if the pump itself can't make pressure (unlikely) or of it's an issue in the pump control side.
I was able to swap front and rear negative flow control pressure hoses, (1 and 5) and the issue did not follow, track and swing continued slow and boom functions remained quick. If anyone has more of an understanding on the system and could correct me that would be great but as of now it seems like a pump control issue.
Ended up the hyd level sensor wire was broken, the oil level sensor wire was broken, and the coolant overflow bottle was a hair low. Operator couldn't tell me if all 3 lights occurred at the time of the hyd issues so I wasn't sure if it was electrical or a hydraulic issue affecting everything.
Got a set of gauges on the negative flow control pressure hoses, the malfunctioning side sits at 350psi and drops to 200 moving the track to full speed, the working side sits at 500psi and drops to 50 when tracking. With the track up in the air if I go to extend the stick the pressure as read from the working pump drops from 500 to almost 0 and the machine starts smoking. All readings were taken at control level 5. The stick function is on the same half of the valve body as the slow track and the rotate, so I'm not sure why my pressure drops on that hose.
It seems the negative flow control hose (nfch) supplies pressure to destroke the pump and as pressure in that hose lowers the main pump strokes more to get higher system psi. Now the question is why I can't get the slow side to drop past 200psi.
Got it squared away, the governor was stuck. The way the system works is when there's pressure on the hose going to the governor it destrokes the pump, in the absence of pressure it makes peak pressure. To test I unplugged the line from the governor and put it into the tank and capped the port on the governor and ran it, the functions weren't moving as quick as they should with the pump supposed to be fully stroked so I pulled the governor and found the spring loaded section was not springing back. After messing with it and moving the rod inside the pump to make sure it was free I reassembled and it was working as normal.
Great to hear you fixed it. While I have no idea if my 325BL has the same governor/pump system, it'll be a great place to start if I do have similar symptoms. Thanks for posting your fix to help others.