753 Drive Problem

[Keith]

Please bare with me, it will take a minute to get to the question. I have a 753 that I have a drive problem with. The unit does okay for about 15 minutes of operation. Then the drives start to get sluggish and eventually it won't move and just groans when you move the levers. I have replaced all the filters (including in-line), tried Bobcat Hyd oil and also 30w motor oil in the system. No difference. Finally broke down and took it to the dealer. They told me they would check it out for 2 or 3 hours of labor and let me know what it needed. After a couple of weeks they have determined that the drive motors need new seals but the main problem is that the Hyrostatic Pump Assembly is shot. The estimate for the repair is over $6,000.00 for a $4000.00 Bobcat. They tell me that the hydrostatic pump is $4500.00 and that they have to be purchased new and can't be re-built. I know that to replace the pump the engine has to come out and I can understand not wanting to risk all that work on a rebuilt part but I don't know of too many equipment parts that cannot be rebuilt. So the questions finally; Can the pumps be rebuilt? Are there any companies that sell rebuilt pumps or will rebuild the one out of the machine? Does anyone sell new ones cheaper than the dealer? Any help, guidance, wisdom, or sympathy will be greatly appreciated!

 

[Tazza]

For starters, motor seal kits are about USD $100 each.
The motor really does need to be pulled to get the pump out, you need to get the pulley off that is really hard to access. The pump can be fixed. Are you the sort of person that has any mechanical skills? If you do, you and a helper can get the engine in and out of the machine. Get the pulley off and pump out, if the swash plates are worn, you can flat plate them to get them to seal correctly again. This is simply a sheet of wet and dry sandpaper on a sheet of glass. Oil it up and rub the plate over it in a figure eight pattern till the wear marks are gone. This will take some time but can be done. Chances are this is all thats wrong. For a total re-build they would replace the swash plates AND rotating groups, the rotating group is very expensive but they are pretty tough. I would suspect the swash plates are scored causing loss of power when warm as the oil will by-pass through the wear marks.
If you do attempt this, you must keep it CLEAN CLEAN, any dirt can cause damage. You won't need to pull the pump rite down, i would only remove one side at a time and only work on the swash plates, not the rotating group as they are a little tricky to get back in place. The steel they are made from is like diamond! so i doubt they are worn, just the bronze plate.
http://www.skidsteerforum.com/DesktopDefault.aspx?tabid=54&frmView=ShowPost&PostID=13406
Look at that, down the bottom shows what the inside of the pump will look like. The swash plates are the ones that you can see brass.

 

[sterlclan]

For starters, motor seal kits are about USD $100 each.
The motor really does need to be pulled to get the pump out, you need to get the pulley off that is really hard to access. The pump can be fixed. Are you the sort of person that has any mechanical skills? If you do, you and a helper can get the engine in and out of the machine. Get the pulley off and pump out, if the swash plates are worn, you can flat plate them to get them to seal correctly again. This is simply a sheet of wet and dry sandpaper on a sheet of glass. Oil it up and rub the plate over it in a figure eight pattern till the wear marks are gone. This will take some time but can be done. Chances are this is all thats wrong. For a total re-build they would replace the swash plates AND rotating groups, the rotating group is very expensive but they are pretty tough. I would suspect the swash plates are scored causing loss of power when warm as the oil will by-pass through the wear marks.
If you do attempt this, you must keep it CLEAN CLEAN, any dirt can cause damage. You won't need to pull the pump rite down, i would only remove one side at a time and only work on the swash plates, not the rotating group as they are a little tricky to get back in place. The steel they are made from is like diamond! so i doubt they are worn, just the bronze plate.
http://www.skidsteerforum.com/DesktopDefault.aspx?tabid=54&frmView=ShowPost&PostID=13406
Look at that, down the bottom shows what the inside of the pump will look like. The swash plates are the ones that you can see brass.

Tazza Is right I fixed mine for less than a hundred bucks...not too hard any questions just yell...Jeff

 

[sterlclan]

Tazza Is right I fixed mine for less than a hundred bucks...not too hard any questions just yell...Jeff

oh yeah this guy does rebuilt parts
http://stores.ebay.com/skidloader-h..._W0QQcolZ4QQdirZ1QQfsubZ9685124QQftidZ2QQtZkm
http://stores.ebay.com/skidloader-hydraulic-parts-source

Link fixed

 

[dlong]

oh yeah this guy does rebuilt parts
http://stores.ebay.com/skidloader-hydraulic-parts-source_Bobcat-Parts_W0QQcolZ4QQdirZ1QQfsubZ9685124QQftidZ2QQtZkm
http://stores.ebay.com/skidloader-hydraulic-parts-source

Link fixed

Does it kill the motor or just make noise?

 

[Keith]

For starters, motor seal kits are about USD $100 each.
The motor really does need to be pulled to get the pump out, you need to get the pulley off that is really hard to access. The pump can be fixed. Are you the sort of person that has any mechanical skills? If you do, you and a helper can get the engine in and out of the machine. Get the pulley off and pump out, if the swash plates are worn, you can flat plate them to get them to seal correctly again. This is simply a sheet of wet and dry sandpaper on a sheet of glass. Oil it up and rub the plate over it in a figure eight pattern till the wear marks are gone. This will take some time but can be done. Chances are this is all thats wrong. For a total re-build they would replace the swash plates AND rotating groups, the rotating group is very expensive but they are pretty tough. I would suspect the swash plates are scored causing loss of power when warm as the oil will by-pass through the wear marks.
If you do attempt this, you must keep it CLEAN CLEAN, any dirt can cause damage. You won't need to pull the pump rite down, i would only remove one side at a time and only work on the swash plates, not the rotating group as they are a little tricky to get back in place. The steel they are made from is like diamond! so i doubt they are worn, just the bronze plate.
http://www.skidsteerforum.com/DesktopDefault.aspx?tabid=54&frmView=ShowPost&PostID=13406
Look at that, down the bottom shows what the inside of the pump will look like. The swash plates are the ones that you can see brass.

Thanks for all of the info guys! The engine does not bog down or even seem to strain. I have taken the engines in and out of a few cars in my day so I'm not afraid to tackle that project. In some ways this looks easier if it was not for all of the hydraulic hoses. I think I'm going to go with Tazza's idea. Get the enging out, pull the pump off and check the swash plates. If they don't look work then I will look to a rebuilder. As a rough guess how long would it take two guys with an awsome set of tools and no Bobcat experience to pull the motor? Thanks!

 

[skidsteer.ca]

Thanks for all of the info guys! The engine does not bog down or even seem to strain. I have taken the engines in and out of a few cars in my day so I'm not afraid to tackle that project. In some ways this looks easier if it was not for all of the hydraulic hoses. I think I'm going to go with Tazza's idea. Get the enging out, pull the pump off and check the swash plates. If they don't look work then I will look to a rebuilder. As a rough guess how long would it take two guys with an awsome set of tools and no Bobcat experience to pull the motor? Thanks!

On the floor in under 2 hours!
Are you sure the dealer wasn't throwing in a new 4 in 1 bucket?!!
Ken