763 reduced power in lift arms and bucket

[tecarr]

Just replaced my relief valves and in line fluid filters. The main seals are working fine, but now the lift arm, bucket tilt, and 4 in 1 cylinders are much slower and less powerful than before ( about 50% ). Also, the hydraulic fluid in the reservoir is a milky yellow in color, though I can't see any bubbles. Could the relief valves I just replaced be a factor? Note- the drive power seems just fine with respect to speed and power.

 

[Tazza]

Its possible its trapped air, but if you only replaced a few items, it should have cleared up fast.
Can you drain off a little oil and let it sit? Just make sure the oil is not white, and the white look is just air bubbles.
If its trapped air, run it then let it sit over night, repeat till the air is all gone.
What relief valves did you change? the main one on the control block? or the ones for the lift cylinders? The inline filters i assume are the case drain filters (alloy cans).

 

[tecarr]

Its possible its trapped air, but if you only replaced a few items, it should have cleared up fast.
Can you drain off a little oil and let it sit? Just make sure the oil is not white, and the white look is just air bubbles.
If its trapped air, run it then let it sit over night, repeat till the air is all gone.
What relief valves did you change? the main one on the control block? or the ones for the lift cylinders? The inline filters i assume are the case drain filters (alloy cans).

I replaced both relief cylinders, and the filters were the case drain filters. I'll try to drain some fluid out to allow the bubbles to dissipate more easily. I guess I'll have to examine the fluid more closely. It may be something else, however, I just replaced the entire 8 gallons or so when I changed the filters. Could water be leaking into the reservoir? Thanks

 

[Tazza]

I replaced both relief cylinders, and the filters were the case drain filters. I'll try to drain some fluid out to allow the bubbles to dissipate more easily. I guess I'll have to examine the fluid more closely. It may be something else, however, I just replaced the entire 8 gallons or so when I changed the filters. Could water be leaking into the reservoir? Thanks

If the seal on the oil tank is bad it could allow water in if the machine is left outside.
Hopefully its just air.

 

[tecarr]

If the seal on the oil tank is bad it could allow water in if the machine is left outside.
Hopefully its just air.

Well it was water in the oil. Purged the bad oil, then had lots of air in the oil. Worked itself out after a couple of cycles. Still have little power in the arms or the bucket, but the drive motors have good power. I do have a red light on the dash; the one that looks like a gear. Not sure what that means. Any ideas

 

[tecarr]

Its possible its trapped air, but if you only replaced a few items, it should have cleared up fast.
Can you drain off a little oil and let it sit? Just make sure the oil is not white, and the white look is just air bubbles.
If its trapped air, run it then let it sit over night, repeat till the air is all gone.
What relief valves did you change? the main one on the control block? or the ones for the lift cylinders? The inline filters i assume are the case drain filters (alloy cans).

Fixed the oil problem, still little power. I changed the main relief and port relief valve on the hydraulic control unit. I did not change the port relief and anti-cav valve. Seems like this symptom wasn't there before I changed the relief valves, maybe I have the wrong equipment. I'm going to put the old ones back in and see what happens.

 

[tecarr]

Fixed the oil problem, still little power. I changed the main relief and port relief valve on the hydraulic control unit. I did not change the port relief and anti-cav valve. Seems like this symptom wasn't there before I changed the relief valves, maybe I have the wrong equipment. I'm going to put the old ones back in and see what happens.

Switched the old ones back in, still weak lift arms. I have the battery of green lights behind the seat, which I believe are all supposed to be steady green. The lift arm light and the gear light are not lit, and every second or so they light up for a second and then the lift arm light flashes once. The sequence then repeats. Not sure what that is supposed to tell me though.

 

[Tazza]

Switched the old ones back in, still weak lift arms. I have the battery of green lights behind the seat, which I believe are all supposed to be steady green. The lift arm light and the gear light are not lit, and every second or so they light up for a second and then the lift arm light flashes once. The sequence then repeats. Not sure what that is supposed to tell me though.

The light sounds like its low charge pressure. The weird thing is if its charge pressure the machine should still lift and tilt, but the drive would be noisy and not as powerful.
You changed the relief valves, i was considering that they could have been stuck from the bad oil, but that is ruled out. Not sure what to check next.
If you can get a 3,500 PSI gauge and hook it to your quick couplers, operate them and see what pressure you get, you should get between 2,500 and 3,000 PSI If they are low, it has to be a pump or relief issue.

 

[tecarr]

The light sounds like its low charge pressure. The weird thing is if its charge pressure the machine should still lift and tilt, but the drive would be noisy and not as powerful.
You changed the relief valves, i was considering that they could have been stuck from the bad oil, but that is ruled out. Not sure what to check next.
If you can get a 3,500 PSI gauge and hook it to your quick couplers, operate them and see what pressure you get, you should get between 2,500 and 3,000 PSI If they are low, it has to be a pump or relief issue.

Thanks; I'll check it. I think I will replace the hyd. oil filter again, since it may have been ruined by the watery oil.