Getting my Bobcat 753 running again, several questions and issues

[dieselfuelonly]

Hey ya'll, I'm having a couple issues with my Bobcat that hopefully someone can help me out with.

To make a long story short its been sitting for about half a year because I had the control valve out. Finally paid to dealer to finish the rebuild and reinstalled it myself yesterday.

I put in new hydraulic filter and fluid.

Issue 1:

I'm not sure which connectors on the wiring harness I'm supposed to plug into the BICS solenoid and the solenoid on top of the chain case (its not the parking brake solenoid, I'm really not sure what it is).

I got it working enough to get it driven around and hauled a couple buckets of dirt, but some stuff isn't working right, so I think I need some help.

In the picture below, there are three connectors coming off the wire harness in one piece of flex tube labeled 1, 2, and 3. Connector 1a is run through a different piece of flex tube and is close to the solenoid on top of the chaincase. I assume that that the solenoid on top of the chaincase (marked ??? in my picture) is what connects to connector 1a. But I had to connect connector 1a to the BICS solenoid to be able to operate the arms and tilt, operating it without solenoid ??? connected. But I don't think thats right.

Would someone mind helping me figure out which connector connects to the BICS solenoid and the solenoid on the chaincase? My service manual isn't much help.

Issue 2:

Soon after starting I could lift the arms and they would fall back down slowly. It got better for a bit where they didn't fall back down, I assumed it was air bleeding out. Also, the tilt held fine right after starting, then after a couple buckets of dirt both the lift and tilt started falling on their own when I let off the pedals, I had to hold the pedal back slightly on both to keep them raised. I stopped the machine and added about another gallon of Bobcat hydraulic fluid since it had sucked the rest into the system. I figured this would solve the "falling problem", but, it still happened. I didn't want to continue operating the machine with the way I had the solenoids connected above, so I went ahead and stopped it after one more quick scoop and dump of some dirt. I checked the hydraulic fluid again and this time it seemed to be OK.

Issue 3: Shortly after I started having issues with the control valve months ago, I checked the chaincase and found it very low on fluid, I can stick my finger way down in there and almost hit nothing. I have some Coastal tractor transmission fluid, JD303 compliant with anti-foam properties. Can I use this in the chaincase? I definatly can't afford to buy 15 gallons of the stuff from Bobcat, and would prefer not to have to buy 15 gallons of engine oil. Will this work OK for now until I can eventually put in engine oil or the Bobcat stuff?

Thanks for any advice!

 

[Willis Bushogin]

oil

Hey ya'll, I'm having a couple issues with my Bobcat that hopefully someone can help me out with.

To make a long story short its been sitting for about half a year because I had the control valve out. Finally paid to dealer to finish the rebuild and reinstalled it myself yesterday.

I put in new hydraulic filter and fluid.

Issue 1:

I'm not sure which connectors on the wiring harness I'm supposed to plug into the BICS solenoid and the solenoid on top of the chain case (its not the parking brake solenoid, I'm really not sure what it is).

I got it working enough to get it driven around and hauled a couple buckets of dirt, but some stuff isn't working right, so I think I need some help.

In the picture below, there are three connectors coming off the wire harness in one piece of flex tube labeled 1, 2, and 3. Connector 1a is run through a different piece of flex tube and is close to the solenoid on top of the chaincase. I assume that that the solenoid on top of the chaincase (marked ??? in my picture) is what connects to connector 1a. But I had to connect connector 1a to the BICS solenoid to be able to operate the arms and tilt, operating it without solenoid ??? connected. But I don't think thats right.

Would someone mind helping me figure out which connector connects to the BICS solenoid and the solenoid on the chaincase? My service manual isn't much help.

Issue 2:

Soon after starting I could lift the arms and they would fall back down slowly. It got better for a bit where they didn't fall back down, I assumed it was air bleeding out. Also, the tilt held fine right after starting, then after a couple buckets of dirt both the lift and tilt started falling on their own when I let off the pedals, I had to hold the pedal back slightly on both to keep them raised. I stopped the machine and added about another gallon of Bobcat hydraulic fluid since it had sucked the rest into the system. I figured this would solve the "falling problem", but, it still happened. I didn't want to continue operating the machine with the way I had the solenoids connected above, so I went ahead and stopped it after one more quick scoop and dump of some dirt. I checked the hydraulic fluid again and this time it seemed to be OK.

Issue 3: Shortly after I started having issues with the control valve months ago, I checked the chaincase and found it very low on fluid, I can stick my finger way down in there and almost hit nothing. I have some Coastal tractor transmission fluid, JD303 compliant with anti-foam properties. Can I use this in the chaincase? I definatly can't afford to buy 15 gallons of the stuff from Bobcat, and would prefer not to have to buy 15 gallons of engine oil. Will this work OK for now until I can eventually put in engine oil or the Bobcat stuff?

Thanks for any advice!

Cant help on the wiring, except go to Bobcat and get a wiring diagram
Oil in chain area, Im not staying this is what Bobcat says to use, but I use 90W/85-90w gear oil. I use which ever one I have available, and Ive never had a problem. You can get it from most parts places, like Napa. I think it runs about $75 for 5 gal

 

[bobcatmechanic]

your question marks in the center is probably a lift arm lock system of some sort i dont remeber exactly the 2 wire plugs are for the aux. your bleed problem is either cyclinder seals bad or someone put the spools in the wrong holes or load checks where left out their is a diffrence in the spools where the grooves and passages are affect alot might check all of that i would have to look at the spools to be able to tell you and if i can even remeber what the diffrence is. I know their is one though lift spool will be your lower spool tilt the top. also you probably over spent on the reseal its easy and quick to do and does not require the removal of the control valve

 

[dieselfuelonly]

Thanks for the help. Does anyone out there have a 753 (mine is a 2000) that they'd be willing to pop the cab on and take a look/picture what plugs into where? I've looked all over this machine and checked through the diagrams in the service manual multiple times and it isn't of much help.

Any help on this would be greatly appreciated, I think before I can do any more troubleshooting I really need to have the solenoids plugged into the correct connectors.

 

[dieselfuelonly]

If it helps at all, I just tried something and thought I would post it.

I still don't have all the solenoids hooked up correctly, this may or may not be the problem. I do not have the solenoid on top of the chaincase (see pic) connected at all.

http://heavyequipmentforums.com/Forum/attachment.php?attachmentid=50354&stc=1&d=1256437952

The lift arms and tilt are still falling when no pressure is put on the pedal. It requires you to hold the pedal back some to keep both from falling when the engine is running.

I started the engine, raised the arms, let go of the pedals, tilt and arms started to lower, then I shut the engine off. They STOPPEDfalling.

Started the engine again and as soon as I pushed the green button to operate the machine, they started falling again. Shut it off and they stopped. Moving the pedals while the engine was off did nothing, they still stayed in the same position. If i pulled the red release handle to my right by the throttle the lift arms would come down.

Could this be happening because the solenoid in the picture is not connected?

 

[spitzair]

If it stops doing this when the engine is off I'm going to lean towards what bobcatmechanic said. Hopefully you'll get 'er fixed soon but if not, next time I'm at home I'll be more than happy to tilt up the cab on my 873 and take a picture or 2, it's a bit different but hopefully the same bits will be in there just maybe in different places... Oh and my 873 is a '98 C-series...

 

[mrfixitpaul]

The solenoid you have the ??? on is for relieving auxiliary hydraulics. It should only get power when you hold the button for aux. pressure relief.