Bobcat 773G Hydraulic Issue

[cdmccul]

Do all of the solenoid coils pull the screwdriver out of your hand when you test them?

 

[wkola]

sounds like you have a bad stem valve . it could be sticking or with age worn so the fluid pass threw . i found my problem and fixed it by replacing the stem valve . and the coil is rated for 10 volts max not 12 volts

 

[Schifference]

sounds like you have a bad stem valve . it could be sticking or with age worn so the fluid pass threw . i found my problem and fixed it by replacing the stem valve . and the coil is rated for 10 volts max not 12 volts

The solenoid tested in the video was from the relief valve. It has 14VDC stamped on the casing. The solenoids on the control valve have tags stating 10 volts. I have not tested the 10 volt solenoids off of the machine. However 3 years ago I did when the Aux Hydraulics only worked in one direction I switched them and it did not change the problem. Then I plugged them in with the wrong wires and it still only went one direction the same way but operated with the switch in the opposite direction.

 

[Schifference]

Okay so is it possible that the toggle switch that is supposed to turn on the flow of Auxiliary fluid stuck or broken? I know nothing about these machines. I would love to be able to use this machine that has 690 hours on it instead of always fixing it. I have spent time reading and testing. I would like to order some parts but not the entire parts catalog.

Here is my thinking possibly a main relief issue or aux hydraulics getting turned on and not shutting off. I hypothesize that it could be a faulty switch. I did not knowingly press the switch used to turn on and test the flow of fluid. Supposedly press it once to turn on and again to shut off. (see pictures). Is it possible it is the main relief valve if not the switch? Pretty inexpensive and looks easy to change. Also I do think I have a bad stem valve because the problem from 3 years ago only allowed operation in one direction.

Upon a glancing thought while typing, would a bad switch on the trigger still keep hydraulic demand going even if the Auxiliary Hydraulics were deactivated from the upper left cab control center or after machine turned off and turned back on without the Auxiliary flow on the left upper control center illuminated and turned on?

Main pressure relief valve only $80. New Valve stem around $225.

If I could get the Auxiliary Hydraulics to turn on and off and work without disabling my lift and tilt, I could deal with one direction flow until I needed to operate something that required both direction flow.

It seems like once I activate the Auxiliary Hydraulic Flow from the Upper left Cab control panel, it does not deactivate even once turned off via the same button that turned it on, via key turning off machine, via the control button to release pressure that turns machine off, or via removing battery cable for extended period and restarting machine. Once the Auxiliary Hydraulics are activated they bog down the machine unless allowed to flow in reverse.

Upon further contemplation it seems like this is what happens:
Lift and tilt works fine.
Engage Aux Hydraulics from Upper Left Cab Control Panel and Hydraulics activate in some manner and bog the engine and disable lift and tilt unless switched to reverse.
Turning off Aux Hydraulics does not disengage the flow of fluid. Engine continues to bog when Aux Hydraulics are not illuminated on upper left control panel indicating that some mechanical valve or whatever the terminology is able to be turned on via electric signal but not turn off.
Whatever is getting mechanically stuck renders lift and tilt inoperable unless flow in opposite direction is engaged.

Seems possible that if a machine was hooked up or pressure gauges, the flow in one direction would not be restricted from lack of flow and disabling lift and tilt. And, maybe if fluid was actually able to flow, the inactivate would actually turn off the pressure because it wouldn't be in a dead space with nowhere to go.

I need to hook up an Auxiliary piece of equipment and see if it works in one direction and allows lift and tilt to function and can be turned off pressure released.

Please look at pictures and give an opinion.

 

[Schifference]

So today I hooked up an attachment. There are definitely issues.
At first the unit worked only one way and lift and tilt worked fine.
I switched solenoids front to back.
I switched stem valve front to back.
I tried running front solenoid off rear wire and rear off front.
I tried one connected while other not.
I tried everything I could think of.

I did get it to operate in both directions but it always wanted to go to one extreme side.
I got it working where it would go in the direction it doesn't want to go but as soon as I stop the toggle it immediately goes back the other way. If I go the direction it does not want to go, and click the trigger it will stop but then I don't think it will go that same direction again.
If I get it to go the direction it doesn't want to go and click the switch to change direction it will stop but will not go the direction it doesn't want to go again unless I stop machine and restart.
It takes a while for it to move in the direction it doesn't want to go.

After all this I switched the solenoids one last time and noted one was very warm. Pretty much too hot to hold for long.
My guess is that is the bad stem valve and by holding the switch in that direction the solenoid heats it up and then when it is hot it kinda works.

I don't know. I ordered one stem valve thinking that one is good and seals/O rings for the other. I think solenoids are good.

I think I could operate a device that only requires flow one direction as it is. I am hoping to fix it soon.

Oh yes another thing. To reset all that is required is to disconnect the solenoid. Then it works properly until you engage Auxiliary hydraulics. Once Auxiliary Hydraulics are activated a current must be keeping a valve in the wrong direction or something. I didn't try it but I think if both Aux stem valve solenoids were disconnected from power the lift and tilt would function as designed.

Definitely a better idea to trouble shoot with a machine attached.

 

[cdmccul]

Then it sounds like a bad switch to me.

I don't have one to look at, but I guess I'd try unplugging the switch in question and probe it with jumper wires. See how it operates without your switch. Maybe you can borrow a known good switch from someone? Or plug your switch into a known good machine?

 

[Schifference]

Then it sounds like a bad switch to me.

I don't have one to look at, but I guess I'd try unplugging the switch in question and probe it with jumper wires. See how it operates without your switch. Maybe you can borrow a known good switch from someone? Or plug your switch into a known good machine?

I know very little about the machine. I have barely used the Auxiliary Hydraulics. I am just a guy that does lots of stuff. With that said I have some questions.
Do all those switches on the joystick handles actually do things?
Are some of them not being used for anything?
Which ones don't do anything?
If one is not doing anything, couldn't I just wire the Auxiliary Hydraulics to a different switch not being used?

On another note. It seems that some parts are getting discontinued or harder to locate. With that said, even if the stem valve is not an issue I will probably just keep it in case some time in the future one goes bad. After reading some in the repair manual and looking at these stem valves and such it appears that this is intricate machining and a lot of engineering went into making these machines work.

Thanks for sharing your thoughts.

 

[wkola]

the right paddle switch is a pwm pulse width modulation switch . you can push a little or a lot with your thumb and the trigger is a on off switch.
the pwm is measured by resistance. it all should run through the computer on the loader. you can measure voltage at the 10 volt wires back probe and get 0 to 6 volts variable while you push the pwm.

 

[Schifference]

I was incorrect in thinking that simply disconnecting the wires to the stem valves would negate the issue and render the bobcat lift and tilt operational.
In my opinion it is not the switch. Yesterday I took the wire that runs the rear solenoid and connected it to the front and the front and connected it to the rear. The Auxiliary Hydraulics need to be on and the switch activated to use lift and tilt however with the wires reversed, the switch needs to be the opposite way so that makes me think the switch is good. Change the wires back the way the belong and the flow changes to the other side of the switch. Presently it has only one solenoid connected to one stem valve and lift and tilt work with Aux Hyd. on and switch on. If I take the wire off the solenoid it is presently connected to and hook up only the other solenoid with the other wire, the lift and tilt will not work. If I remove the stem valves and put them back in the lift and tilt will work without the need for Auxiliary Hydraulics to be on regardless if both solenoids are connected or not. Once Auxiliary Hydraulics engaged, engine bogs, and lift and tilt will not work unless Aux Hydro on. i have switched solenoids and it doesn't change anything.

So I don't think it is solenoid or switch. My guess at the moment is stem valve. I am waiting for a new one to arrive.

 

[Schifference]

Kinda update:
This machine has not had a lot of use. The other day I hooked up the backhoe attachment. It functioned. I am not sure if machine was working in reverse or not but I was able to dig a hole. At first I needed to have the Auxiliary Hydraulics engaged and the trigger pulled to get lift and tilt working. After using the backhoe it appears that the lift and tilt function as intended all the time. I have not had the need to use both forward and reverse auxiliary hydraulics so I don't know if both directions work or not.

I have received a stem valve from Bobcat and have not at this time replaced it or don't even know if I need it.

Maybe valves were just sticking from lack of use and have freed themselves up. I don't know. I will continue to report as I use the machine more.

 

[cdmccul]

At the moment, I think that's a good theory... That what it needed was warmed up and used more.

It's happy now that it got to feel useful, perhaps.

 

[cdmccul]

But yes, please keep us updated.

 

[Schifference]

My guess is there is nothing wrong with the hydraulics.

As per 3 years ago they run in reverse. I just swapped the lines on my attachment and the 4 in 1 bucket stays closed and opens when I turn the switch.

Rather than change the fittings on each attachment I would ever hook up, I am considering changing the fittings on the bobcat so any and all attachments will work properly.

 

[Schifference]

Still in the logic, thinking, brainstorming, mode.
Yesterday I put the 709 backhoe attachment on and it was not working very well. I checked hydraulic oil level and added some which did nothing to help.
I opened the cab enclosure because I was thinking that maybe the backhoe was not operating properly because Auxiliary hydraulics were operating in reverse. I was contemplating changing the connections. When looking at the connectors at the front of the machine, one is longer than the other following the contour of the cab and machine. If I just switched the connectors there that wouldn't seem right. I followed the lines to the back of the engine compartment and noted them going under the cab. I lifted the cab to see if there was a place where someone might have mistakingly switched the Auxiliary Hydraulic lines but noted they are hard metal lines all the way to the pump. So I didn't think that had happened. While inspecting the hydraulic lines I noted that I was operating with one of my auxiliary solenoids disconnected. I disconnected it a few days ago when doing all the troubleshooting diagnostics. After plugging in that solenoid, holy smokes, I am digging that 709.
With that said, I will need to see what happens when I put that 4 in 1 bucket that I switched the hose ends back on.
From what I can tell, according to the diagrams for up and down, left and right, etc, etc... on the 709, all the functions are working in the correct direction.
One more thing is nothing seems to render lift or tilt non-functioning as before. My guess is that lack of use rendered sticky valves.
I will continue to update.
At this point, I would advise any person having difficulty with auxiliary hydraulics on a machine that has not used auxiliary hydraulics often or in a long time, or not at all, is to put on an attachment and keep trying to use it. Maybe if you keep trying to use it and the valves heat up and the fluid gets hot, things will free up and work as they should.
As mentioned, I can't say I have no more issues but will report back here when I know more.

 

[Schifference]

Took off the Backhoe yesterday and put on a 4 in one bucket. Once again Auxiliary hydraulics would not open the bucket and lift and tilt would not function without Auxiliary Hydraulics on with trigger pulled.

This morning I replaced one of the stem valves. I only purchased one. I figured if it didn't fix the issue I would take it out and switch it with the other one. Well it worked on first attempt.

Bottom line is bad stem valve.

 

[cdmccul]

Woohoo! Congrats on finding it. As LEGO Batman would say "FIRST TIME!"

 

[lmcl123]

Took off the Backhoe yesterday and put on a 4 in one bucket. Once again Auxiliary hydraulics would not open the bucket and lift and tilt would not function without Auxiliary Hydraulics on with trigger pulled.

This morning I replaced one of the stem valves. I only purchased one. I figured if it didn't fix the issue I would take it out and switch it with the other one. Well it worked on first attempt.

Bottom line is bad stem valve.

I think I own your identical twin Bobcat 773G with. I have the same problem with mine. Bobcat told me 3 years ago it was the valve stems/solenoid. I replaced them, and it fixed nothing. I used it by using the work around that you used. I took it in two months ago because my lift stopped lowering. They still haven't figured that out, but they did fix the aux problem. After consulting with bobcat national office, they again replaced the valve stems (even though the local guys checked mine and determined they were good). guess what, it fixed the aux problem. I don't know if I should be happy or pissed!
Does yours have the AHC , and can you tell me what year yours is, the serial number and also if it has the float button on the left side handle (yellow button). The local office contacted me today on my lift/lower problem and may have figured out the solution, but I won' elaborate until the part arrives, and they install it, and it works. I can then give you a description of the next problem you will most likely encounter.

 

[lmcl123]

Took off the Backhoe yesterday and put on a 4 in one bucket. Once again Auxiliary hydraulics would not open the bucket and lift and tilt would not function without Auxiliary Hydraulics on with trigger pulled.

This morning I replaced one of the stem valves. I only purchased one. I figured if it didn't fix the issue I would take it out and switch it with the other one. Well it worked on first attempt.

Bottom line is bad stem valve.

I think I own your identical twin Bobcat 773G . I have the same problem with mine. Bobcat told me 3 years ago it was the valve stems/solenoid. I replaced them, and it fixed nothing. I used it by using the work around that you used. I took it in two months ago because my lift stopped lowering. They still haven't completely figured that out, but they did fix the aux problem. After consulting with bobcat national office, they again replaced the valve stems (even though the local guys checked mine and determined they were good). Guess what, it fixed the aux problem. I don't know if I should be happy or pissed!
Does yours have the AHC , and can you tell me what year yours is, the serial number and also if it has the float button on the left side handle (yellow button). The local office contacted me today on my lift/lower problem and may have figured out the solution, but I won' elaborate until the part arrives, and they install it, and it works. I can then give you a description of the next problem you will most likely encounter.

 

[JxxxOxxxE]

Did this ever get resolved? I have/had the same problem that the dealer diagnosed as an internally cracked control valve...