631 right drive problem

[Tazza]

If my left side drive works fine but the right don't, does it mean my pump is good?

Thats a geroler setup (if i spelled it correctly). Totally normal to have space between the pins and the star.
You really shouldn't have opened the motor up, if you fiddled inside you may have messed the timing up for the valve plate. Thats why you try putting the motor on the other side first and if the motor works its the pump. With the hydraulic lines open you should be able to turn the shaft though. Is it locked up solid?
These machines have 3 pumps all in a line. The first one from memory drives the right side, the middle one is the left side and the front is for the hydraulics. It also acts as a charge pump for the first 2 pumps.

 

[Tazza]

Thats a geroler setup (if i spelled it correctly). Totally normal to have space between the pins and the star.
You really shouldn't have opened the motor up, if you fiddled inside you may have messed the timing up for the valve plate. Thats why you try putting the motor on the other side first and if the motor works its the pump. With the hydraulic lines open you should be able to turn the shaft though. Is it locked up solid?
These machines have 3 pumps all in a line. The first one from memory drives the right side, the middle one is the left side and the front is for the hydraulics. It also acts as a charge pump for the first 2 pumps.

Just to be clear, the pumps are separate. If one pump dies you will loose drive on one side only, it will not make both sides fail unless its a catastrophic failure that breaks the drive shaft.

 

[alexvbugman]

Just to be clear, the pumps are separate. If one pump dies you will loose drive on one side only, it will not make both sides fail unless its a catastrophic failure that breaks the drive shaft.

finally got back to working on this problem, and can't figure it out. I reinstalled the motor (correctly this time) Tazza was right, I had to put it together a certain way because of the valve plate. So after I fired it up on blocks I had right side drive again, but when I let it down it won't move (right side only) so I unscrew the allen bolt on the side of the motor and it doesn't seem to have alot of pressure. Left side drive is fine as are the bucket functions.

 

[sterlclan]

finally got back to working on this problem, and can't figure it out. I reinstalled the motor (correctly this time) Tazza was right, I had to put it together a certain way because of the valve plate. So after I fired it up on blocks I had right side drive again, but when I let it down it won't move (right side only) so I unscrew the allen bolt on the side of the motor and it doesn't seem to have alot of pressure. Left side drive is fine as are the bucket functions.

with the machine is in the air,unhook the hoses from the pumpin the middle and switch them front to back ,this will make the motors spin backwards(the handles will be oppisite sides as well) but it will tell you if it is the pump or the motor you may have to put it on the ground to really tell. good luck.....Jeff

 

[alexvbugman]

with the machine is in the air,unhook the hoses from the pumpin the middle and switch them front to back ,this will make the motors spin backwards(the handles will be oppisite sides as well) but it will tell you if it is the pump or the motor you may have to put it on the ground to really tell. good luck.....Jeff

I switched the lines and the opposite side quit working, that means the hydro motor is ok. Does it mean it is the hydraulic pump, or maybe a blocked passage up top? I can't figure this one out. There is fluid at the motor, it just isn't high pressure.

 

[Tazza]

I switched the lines and the opposite side quit working, that means the hydro motor is ok. Does it mean it is the hydraulic pump, or maybe a blocked passage up top? I can't figure this one out. There is fluid at the motor, it just isn't high pressure.

It has to be the hydrostatic pump.
You will need to remove the entire pump and crack it open and work out what the problem is. The rear section is for the left hand side and the middle one is the right. The one at the front is the hydraulic pump, this isn't the cause of the problem.
I will try and post a PDF of the pump tonight. If i forget check my profile and send me an e-mail to remind me. That or you can e-mail me anyway and i will e-mail the pdf direct to you.
This way you will know what to expect when you open the pump up.

 

[Tazza]

It has to be the hydrostatic pump.
You will need to remove the entire pump and crack it open and work out what the problem is. The rear section is for the left hand side and the middle one is the right. The one at the front is the hydraulic pump, this isn't the cause of the problem.
I will try and post a PDF of the pump tonight. If i forget check my profile and send me an e-mail to remind me. That or you can e-mail me anyway and i will e-mail the pdf direct to you.
This way you will know what to expect when you open the pump up.

http://users.tpg.com.au/tazza_/i3106s.pdf
Check it out, thats what you can expect when you crack the pump open. The last thing you can check is the relief valves, they i THINK are on the right side of the pump (looking from the bucket) behind 2 plugs where the high pressure hoses join in. I believe the left side are the replenishing valves.

 

[pondfishr]

they arent too bad remove the seat, and you can see them bolted to both sides of the chain case tazza knows more about the seals than me if you need I can help with some scans of the service manual I have a 630 Good luck, Jeff

I have a friend has a 630 manual with too much fluid in the chain case. His problem is that his chain case overfills with hydraulic fluid. Does anybody have a detailed drawing for changing out the O rings that are mentioned here.

 

[Tazza]

I have a friend has a 630 manual with too much fluid in the chain case. His problem is that his chain case overfills with hydraulic fluid. Does anybody have a detailed drawing for changing out the O rings that are mentioned here.

It should be as simple as removing the hydro lines and the 4 bolts and pull the motor out. I did hear that some models have a bolt that holds the end of the shaft to a sprocket.
With the motor out use a pick to remove the O ring inside the bronze bush and install a new one and you are set!

 

[Tazza]

It should be as simple as removing the hydro lines and the 4 bolts and pull the motor out. I did hear that some models have a bolt that holds the end of the shaft to a sprocket.
With the motor out use a pick to remove the O ring inside the bronze bush and install a new one and you are set!

Of course oil it up before installation to prevent pinching the new seal when you push it back on the gear box.

 

[pondfishr]

Of course oil it up before installation to prevent pinching the new seal when you push it back on the gear box.

Thanks Tazza! My friend is the equipment operator that I have been talking to about helping me change the axle seals on my 743. I will let him know what you said and we really appreciate it. I checked the chain case fluid level on my machine this afternoon and it is still full. I don't think I could get lucky enough that the reason it is leaking is it has too much fluid in it. Is that a possibility? I have a little job to do this weekend and I am going to use the machine to see how it does. Another observation is the wheel that is leaking has oil stains on the outer side where the wheel screws to the hub. Oh well maybe one day I get that new T180 track machine I dream about at night. Until then I will keep maintaining what I have.

 

[Tazza]

Thanks Tazza! My friend is the equipment operator that I have been talking to about helping me change the axle seals on my 743. I will let him know what you said and we really appreciate it. I checked the chain case fluid level on my machine this afternoon and it is still full. I don't think I could get lucky enough that the reason it is leaking is it has too much fluid in it. Is that a possibility? I have a little job to do this weekend and I am going to use the machine to see how it does. Another observation is the wheel that is leaking has oil stains on the outer side where the wheel screws to the hub. Oh well maybe one day I get that new T180 track machine I dream about at night. Until then I will keep maintaining what I have.

Too much oil will cause it to leak.
If the seal is bad you will find it pools up in the hub

 

[pondfishr]

Too much oil will cause it to leak.
If the seal is bad you will find it pools up in the hub

Right after I topped it off and grading my driveway I noticed I was leaving fluid marks in the gravel. It was leaking bad enough that the inside sidewall of my tire was covered in oil. Does this sound like a fluid leak or overfill or can you tell with that much information. Also my friend has agreed to help me if we replace the 743 seals. On his 630 all four of his wheels look oil stained and the hydro is dumping into the chain case. He got a pretty good deal on it. We rented a track machine that the homeowner paid for and we fixed a fill line that took about 6-7 hours. The homeowner owned the 630 "that has a brand new engine installed" but leaks fluid in the chain case like crazy. They gave the machine to him as payment for the labor running the T180 track machine.

 

[Tazza]

Right after I topped it off and grading my driveway I noticed I was leaving fluid marks in the gravel. It was leaking bad enough that the inside sidewall of my tire was covered in oil. Does this sound like a fluid leak or overfill or can you tell with that much information. Also my friend has agreed to help me if we replace the 743 seals. On his 630 all four of his wheels look oil stained and the hydro is dumping into the chain case. He got a pretty good deal on it. We rented a track machine that the homeowner paid for and we fixed a fill line that took about 6-7 hours. The homeowner owned the 630 "that has a brand new engine installed" but leaks fluid in the chain case like crazy. They gave the machine to him as payment for the labor running the T180 track machine.

That was a nice deal.
It would need to be really over full to leak that bad, and even then it should leak out the breather hole and not the seal(s). I do believe the seals are the problem and not oil level. My 731 would leave a small puddle over night but it was not visible when the machine was in use. It was a very minor leak. If it leaks that much fluid into the chain case it really needs looking at. It won't cause any real damage but it will waste a lot of oil.
You may want to measure the axle hubs on the 630 and see if they are the same as the 743 as the seal tool may be suitable for both machines. Then you can help each other out with replacing the seals on both machines.

 

[pondfishr]

That was a nice deal.
It would need to be really over full to leak that bad, and even then it should leak out the breather hole and not the seal(s). I do believe the seals are the problem and not oil level. My 731 would leave a small puddle over night but it was not visible when the machine was in use. It was a very minor leak. If it leaks that much fluid into the chain case it really needs looking at. It won't cause any real damage but it will waste a lot of oil.
You may want to measure the axle hubs on the 630 and see if they are the same as the 743 as the seal tool may be suitable for both machines. Then you can help each other out with replacing the seals on both machines.

Could you point me to the breather hole location. I have no idea where it is located and that would be good information to know.

 

[Tazza]

Could you point me to the breather hole location. I have no idea where it is located and that would be good information to know.

I'm not too sure where it is on that machine but on my 743 its under the hydro pump covered by the arm that links between the lift pedal and the spool, little bonded bronze thing like what the use for filters. Others have it under the brake pedal i'm not sure if mine has one here too or not.
Either way, it will be under the brake pedal or under the hydro pump. The one under the brake is a different style.

 

[skidboy]

I'm not too sure where it is on that machine but on my 743 its under the hydro pump covered by the arm that links between the lift pedal and the spool, little bonded bronze thing like what the use for filters. Others have it under the brake pedal i'm not sure if mine has one here too or not.
Either way, it will be under the brake pedal or under the hydro pump. The one under the brake is a different style.

unfortunately a 600 series is nothing like a 700 series.this was stated earlier in this thread. to assume that all bobcats are the same as an old 743 will cause a lot of miss-diagnosis

 

[alexvbugman]

unfortunately a 600 series is nothing like a 700 series.this was stated earlier in this thread. to assume that all bobcats are the same as an old 743 will cause a lot of miss-diagnosis

Hey guys I finally took my pump out and cracked it open, the only thing I found was some significant wear grooves in the wafer plate,everything else looks great. Any idea where I can find these, or should I go through Bobcat direct. Thanks

 

[Tazza]

Hey guys I finally took my pump out and cracked it open, the only thing I found was some significant wear grooves in the wafer plate,everything else looks great. Any idea where I can find these, or should I go through Bobcat direct. Thanks

If you have the patience you can do them your self with a sheet of glass and wet and dry sand paper. If you remove the grooves it will be like new. If you buy new parts you will fall over when you find out how much they cost!!!
I think it was sterlclan that did it, a link the the pictures is here: http://www.skidsteerforum.com/DesktopDefault.aspx?tabid=52&gallerypage=0&path=hystat%20wear%20plate%20repair
It can be done for the cost of time and a gasket. If you replace sthe swash plates and rotating groups you will be up for thousands!.

 

[Tazza]

If you have the patience you can do them your self with a sheet of glass and wet and dry sand paper. If you remove the grooves it will be like new. If you buy new parts you will fall over when you find out how much they cost!!!
I think it was sterlclan that did it, a link the the pictures is here: http://www.skidsteerforum.com/DesktopDefault.aspx?tabid=52&gallerypage=0&path=hystat%20wear%20plate%20repair
It can be done for the cost of time and a gasket. If you replace sthe swash plates and rotating groups you will be up for thousands!.

FOUND IT!!!
http://www.skidsteerforum.com/DesktopDefault.aspx?tabid=54&frmView=ShowPost&PostID=7745
It worked a treat, flat plate the wear plates and you will need to touch up the rotating groups too, they won't take much as they are harder than the wear plates (swash plates).
Good luck with it, if you have any questions on it just yell. I have had one of these pumps open before, they are fairly simple but you need to keep them clean clean clean.