bobcat 763 has trouble moving over terrain

[adamjedgar]

Hi guys, I have two bobcat machines...one is a 763 skid steer and the other is a bobcat 430 fast track excavator. This is going to sound strange however, both machines recently have started to produce the almost exact same problem...they are having great difficulty moving forward or backwards. It is as if they are both low on hydraulic oil, however, i have changed the hydraulic filter and oil on both machines in the last 5 hours with new ISO 68 Great Western Hydraulic Oil. there is no shuddering in the normal hydraulic operations for bucket or arm movements...it is simply that neither machine wants to move forward or backwards (especially up any kind of incline or pushing dirt). Bobcat told me they think it is the oil...ie i should be using only bobcat brand oils...however, i do not trust that advice without an explanation as i have heard this same argument with every single manufacturer or any product (whether it be earth moving machinery or computer printers). Can someone provide any insight into what may actually be wrong with my machines (ie is it damaged final drives in both or could it really be just the oil brand causing the problem?)

 

[adamjedgar]

I have an update to my problem...after some discussions with an oil company i have been advised that one should not use hydraulic oils in hydrostatic systems. Both the bobcat 763 and the Bobcat 430 fast track excavator use hydrostatic final drive systems for moving the machines across the ground. This explains why both have shown what appears to be identical issues after my having changed the oil (ie having great difficulty moving across the ground) The oil supplier did a search for me and found out that i should be using 15W40 Engine oils only for the hydraulic fluid in both machines because of the hydrostatic drives on them. I will drain the oils on both of my machines and provide an update in a few days after i have done so and tried them again. I hope this is of help to someone else with bobcat equipment that has "hydrostatic" type drive systems. Do not use normal hydraulic fluids in these type of machines...only engine oil.

 

[TriHonu]

I have an update to my problem...after some discussions with an oil company i have been advised that one should not use hydraulic oils in hydrostatic systems. Both the bobcat 763 and the Bobcat 430 fast track excavator use hydrostatic final drive systems for moving the machines across the ground. This explains why both have shown what appears to be identical issues after my having changed the oil (ie having great difficulty moving across the ground) The oil supplier did a search for me and found out that i should be using 15W40 Engine oils only for the hydraulic fluid in both machines because of the hydrostatic drives on them. I will drain the oils on both of my machines and provide an update in a few days after i have done so and tried them again. I hope this is of help to someone else with bobcat equipment that has "hydrostatic" type drive systems. Do not use normal hydraulic fluids in these type of machines...only engine oil.

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You may want to take a read through Let's revisit the oil vs. hydraulic question??? thread.
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[adamjedgar]

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You may want to take a read through Let's revisit the oil vs. hydraulic question??? thread.
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I think the following quotes from that thread and other forums need consideration... -------------------------------------------- quote from this forum you mentioned... "Like it was stated before Bobcat doesn't publish what grade their branded oil is. But since they only have one grade that they sell we can assume that it's an all weather multi-grade oil. Very few oil manufacturers make a multi-grade hydraulic oil and most are branded by one of the farm equipment manufacturers, John Deere Hy-Gard, Kubota Super UDT and Amsoil Synthetic Tractor Hydraulic are the couple I found." a quote on another forum says... "if the Bobcat tractor is anything like their other equipment they use proprietary Bobcat hydraulic fluid in their machines. Standary hydraulic fluid will DAMAGE Bobcat pumps and seals. I have read on other forums where the skidsteers can either run on the recommended Bobcat brand hydraulic fluid or 10w 30 motor oil will suffice once they are out of warranty. That might sound odd but that is what is posted be reliable sources." and this... "Because of the differences between "hydraulic" fluid and "hydrostatic" fluids, wouldn't it be good to have a separate thread for "hydrostatic" fluids to emphasize that difference? Isn't it true that running "hydraulic" fluid where "hydrostatic" fluid is required can have disastrous results to a machine?" --------------------------------------------------- I did a bit of searching around looking at other machines such as ride on mowers and tractors etc, and it seems that hydrostatic systems should not use ISO 68 oils...the viscosity is wrong. Most seem to say the same thing...use 15W 30 engine oils when the proprietry hydrostatic oils are not sourced. I have used ISO 46 in the past and whilst my excavator does track around with it, and the bobcat seemed ok, however on the excavator, the two speed travel controller engaged in "rabbit" speed sees the machine struggle to make headway on flat ground in this mode. Clearly, even ISO 46 clearly isnt good enough for it. I am going to try to get Bobcat to spill the beams on their oil specifications today, however, i suspect that my best option is to simply change everything over to a decent synthetic engine oil and use that instead...from what i can see on bobcats website these days, they are using synthetic oils now for hydraulics and engines (although there is still a premium grade engine oil in their list).

 

[adamjedgar]

I think the following quotes from that thread and other forums need consideration... -------------------------------------------- quote from this forum you mentioned... "Like it was stated before Bobcat doesn't publish what grade their branded oil is. But since they only have one grade that they sell we can assume that it's an all weather multi-grade oil. Very few oil manufacturers make a multi-grade hydraulic oil and most are branded by one of the farm equipment manufacturers, John Deere Hy-Gard, Kubota Super UDT and Amsoil Synthetic Tractor Hydraulic are the couple I found." a quote on another forum says... "if the Bobcat tractor is anything like their other equipment they use proprietary Bobcat hydraulic fluid in their machines. Standary hydraulic fluid will DAMAGE Bobcat pumps and seals. I have read on other forums where the skidsteers can either run on the recommended Bobcat brand hydraulic fluid or 10w 30 motor oil will suffice once they are out of warranty. That might sound odd but that is what is posted be reliable sources." and this... "Because of the differences between "hydraulic" fluid and "hydrostatic" fluids, wouldn't it be good to have a separate thread for "hydrostatic" fluids to emphasize that difference? Isn't it true that running "hydraulic" fluid where "hydrostatic" fluid is required can have disastrous results to a machine?" --------------------------------------------------- I did a bit of searching around looking at other machines such as ride on mowers and tractors etc, and it seems that hydrostatic systems should not use ISO 68 oils...the viscosity is wrong. Most seem to say the same thing...use 15W 30 engine oils when the proprietry hydrostatic oils are not sourced. I have used ISO 46 in the past and whilst my excavator does track around with it, and the bobcat seemed ok, however on the excavator, the two speed travel controller engaged in "rabbit" speed sees the machine struggle to make headway on flat ground in this mode. Clearly, even ISO 46 clearly isnt good enough for it. I am going to try to get Bobcat to spill the beams on their oil specifications today, however, i suspect that my best option is to simply change everything over to a decent synthetic engine oil and use that instead...from what i can see on bobcats website these days, they are using synthetic oils now for hydraulics and engines (although there is still a premium grade engine oil in their list).

if one does a search on the gulf western oils website http://www.datateck.com.au/lube/GulfWesternAus/ and enters bobcat 763 into the search box...the following oils come up for use in both engine and hydrostatic systems... TOP DOG® INDESTRUCTIBLE 15w40 CK4 or TOP DOG GLOBAL® MINERAL 15w40 CJ4/SN Both of the above are provided to Gulf Western Oil company based on 3rd party industry technical research experts specifically for the machine in question as outlined by Bobcats own lube specifications.

 

[TriHonu]

if one does a search on the gulf western oils website http://www.datateck.com.au/lube/GulfWesternAus/ and enters bobcat 763 into the search box...the following oils come up for use in both engine and hydrostatic systems... TOP DOG® INDESTRUCTIBLE 15w40 CK4 or TOP DOG GLOBAL® MINERAL 15w40 CJ4/SN Both of the above are provided to Gulf Western Oil company based on 3rd party industry technical research experts specifically for the machine in question as outlined by Bobcats own lube specifications.

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If you want the best answer to your question, identify the hydrostatic pump in your excavator/loader and contact the pump manufacturer.
Bobcat did not manufacture the pump they did. Their technical support will be able to tell you the optimum oil for that pump.
When I contacted Sauer Danfoss, they were more than willing to answer my questions. They gave me a list of oils that will work, some will provide the optimum properties that allow the pump to operate at maximum performance with the longest life span. Many others will work but may not perform as well or may not provide the the optimum conditions to maximize pump life.
Common sense should tell you that an oil engineered to operate inside an internal combustion engine will have an additive package to address those particular conditions. I don't believe those specific conditions are observed inside a hydrostatic pump, thus motor oil may work, but is not the optimal oil.

 

[farmshop]

&nbsp
If you want the best answer to your question, identify the hydrostatic pump in your excavator/loader and contact the pump manufacturer.
Bobcat did not manufacture the pump they did. Their technical support will be able to tell you the optimum oil for that pump.
When I contacted Sauer Danfoss, they were more than willing to answer my questions. They gave me a list of oils that will work, some will provide the optimum properties that allow the pump to operate at maximum performance with the longest life span. Many others will work but may not perform as well or may not provide the the optimum conditions to maximize pump life.
Common sense should tell you that an oil engineered to operate inside an internal combustion engine will have an additive package to address those particular conditions. I don't believe those specific conditions are observed inside a hydrostatic pump, thus motor oil may work, but is not the optimal oil.

We use and have always used a universal tractor hydraulic oil in our skidsteers with no issues. We have ran them to 10000 hours with no pump or motor problems

 

[cwjohndeere]

We use and have always used a universal tractor hydraulic oil in our skidsteers with no issues. We have ran them to 10000 hours with no pump or motor problems

The bobcat brand oil is isn't that much more expensive for me compared to anything else that its not worth messing with I just use the Bobcat oil. The dealer here charges $70.99 for a 5 gallon bucket which you can hardly buy the cheap universal hydraulic fluid or engine oil for. Just a personal opinion.

 

[7LBSSMALLIE]

I have an update to my problem...after some discussions with an oil company i have been advised that one should not use hydraulic oils in hydrostatic systems. Both the bobcat 763 and the Bobcat 430 fast track excavator use hydrostatic final drive systems for moving the machines across the ground. This explains why both have shown what appears to be identical issues after my having changed the oil (ie having great difficulty moving across the ground) The oil supplier did a search for me and found out that i should be using 15W40 Engine oils only for the hydraulic fluid in both machines because of the hydrostatic drives on them. I will drain the oils on both of my machines and provide an update in a few days after i have done so and tried them again. I hope this is of help to someone else with bobcat equipment that has "hydrostatic" type drive systems. Do not use normal hydraulic fluids in these type of machines...only engine oil.

check drive belt tension. any charge pressure codes?