I have a 2003 Bobcat 753 model G. After I replaced the seals in the lift pistons and tilt cylinder, after a while the oil pressure warning light came on (bottom right). I have checked the level and it’s ok and there is no metal- shavings or anything in the filter. The machine works as it should even when the light comes on. Could the sensor been damage because of the air in the system after the seal change?
Charge pressure or engine oil pressure light? Did you check for an active code?
Hi, I don’t have any active code at the moment. But now when I checked for error code the oil pressure light is not on either... When the light was on it was the bottom right one.
The warning light at the RH end of the bottom row is for a plugged hydraulic oil filter, not low hydraulic oil pressure. Check this link and look at parameters 1413, 1414, & 1415 - https://www.iso.org/obp/ui/#iso:pub:PUB400001:en
Thanks for the tip! I had checked the filter and couldn't see anything bad but now that I have changed it everything seems to be working. However, I occasionally have problems with lowering the bucket. It can be raised and tilted but it does not work to lower. I have a machine with ACS and acuators. No error code! When it is like that, I have lowered the bucket by pressing the middle button on the left controller while lowering the bucket with the pedal. (Se attached picture) Could it be a bad solenoid? Is it then one of the ones sitting at the top of the hyudral package? How do you know which one who is for lowering bucket? Or is it the one that is commonly called the main-release valve?
Is the ACS light in the right side dash lit up when it does not work? If it is an actuator problem, I would expect the light to be on, indicating an error code. Codes will not show in hour meter display until the lights button is held for several seconds, and then only active codes.
The actuators is new and also the ACS controller. The ACS light is off. It’s almost as something happens when I use the Float-button. And when I pusch the middle button to the left I can lower the bucket again. Is that the button for aux hydraulic?
On my 2003 S250 that button is for momentary auxiliary. Like open/close a grapple. Only works if the auxiliary it turned on with the button near the green push to operate button is pushed.
I'm trying to remember.. .. I ran into one with a similar issue, the aux spool was drifting and loading the aux circuit, hitting the aux switch would shift yhe spool back to center, if memory serves was a bad aux solenoid. Would act up even with aux not turned on.
Is that one of the ”silver” ones on top of the hyudralic-package?
Right now, I can't lower the bucket at all. The only time it works is when I turn off the machine — then it lowers once. It feels like it's going into 'float mode' because it drops all the way down by itself. I tried swapping the two electric solenoids on top of the hydraulic unit, but it made no difference. Do you have any good suggestions? Could it be the main release valve on the side?
Problem is, it won't matter which way the aux spool is shifted, so swapping won't help. Also, you will need to replace the valve stem, not just the coil. And no good way to tell which one it is. . .. I would try unplugging both of the aux solenoids, just in case it is electrical. (Doubt it)
Thanks for the great help! I’m going to order new coils. I’ve seen that the AUX solenoid should measure between 9–11 ohms, so I should be able to check that. Is it this one that I need two of?
Yes, that is a valve stem, (not coil). However a quick look gives me a part number of 6665758 for the aux proportional valve stem. Need a serial to be sure.
Okey, Thanks! My serial nr is 516227178
Attached is the Bobcat parts page. See why serial is important? #58 appears to be the valve in question, and we need to go to the second stem serial break to find your serial included. Part # 6688743
It's a bit hard to understand the parts manual, but in my service manual I found this (see attached). The one I marked with a circle was corroded and in bad shape. Is that the same one you're referring to?
That is a much better image! Yes, that is the same valve, and seems likely you have found the problem.
Now I have tried replacing the stem valve control 6688743, but there’s no difference. I have measured the solenoids to 5.4 ohms for the aux electric solenoid. The solenoid located on the horizontal part of the block measured at 10.4 ohms (the instructions say up to 10 ohms). I have also tried running without the aux solenoid connected. No matter what I try, it’s not possible to lower the bucket. Now the foot pedal has also stopped working both up and down. It’s completely locked, but no error code. The hand controls work, but only upward. Sometimes I’ve gotten the error code 32-40. Do you have any other ideas?
So if you have it switched to foot controls, nothing works, but if set to hand controls it partly works?
Yes, exactly. I will check all the connections to the pedal for lift as som I have little spare time.
Hi, I’ve managed to get the foot pedal working again – it turned out to be a broken wire. That probably happened when I was pulling on the cables to check for any damage. However, it still only lowers once and then stops. Still no error codes, so it feels like a mechanical fault in the hydraulic block. Do you know if the electric solenoids H1 and H3 are supposed to measure 5.4 ohms?
I would check the spool centering springs next. (#s 27 or 45 in the parts attachment). Also I have seen the aluminum caps, #37, 39, 43- corrode and allow the spring to pop out.
About 50 hours ago I replaced the actuators, the seals on the lift and tilt spools including the springs. So all of that is new. I haven’t removed No. 45, so that spring for AUX spool are untouched. Is it possible that it can ”lock”the lift spool? Another thought: I don’t have a door, but the machine used to have one. Is there any safety switch that could prevent lowering if the door is opened?