This cant be good-oil gushing out of chaincase fill plug!!??

[jinxie]

'94 753 I noticed my hydraulic oil was low, so I filled it, but thought it was strange that I added over a gallon and never had a drop previosuly on the shop floor. So I checked the level again after about a few hours of use. Its down again. I was checking other levels in the machine when I went to remove the plug from the front of the machine behind the bucket (chain case?), oil came gushing out of there!! I know I didnt overfill it. The level was always at the bottom of the threads. I suspect my hydraulic oil is in there......but how?? I have a manual.... Thanks

 

[Fishfiles]

The oil is coming thru the travel motor and getting into the chain case , prices on parts flucuate like the stock market , last time I got one it was about $75 for a seal kit , I'd do both at the same time , you can troubleshot it to determine which side is leaking , but I find the time it takes to troubleshot it and the other side is usually right behind in leaking that it is better to just do both at the same time , not too hard about 2 hours per side of labor , getting the kit will probally be easier for you if you take the motor out first and get the tag number off the motor as the 753 used a couple of different motors and the serial number usually don't get it right

 

[Tazza]

The oil is coming thru the travel motor and getting into the chain case , prices on parts flucuate like the stock market , last time I got one it was about $75 for a seal kit , I'd do both at the same time , you can troubleshot it to determine which side is leaking , but I find the time it takes to troubleshot it and the other side is usually right behind in leaking that it is better to just do both at the same time , not too hard about 2 hours per side of labor , getting the kit will probally be easier for you if you take the motor out first and get the tag number off the motor as the 753 used a couple of different motors and the serial number usually don't get it right

Check your case drain filters to ensure they are not blocked.
If you pull the motors out, you will notice a big black seal on a shaft going into the chain case. If this is damaged oil will flow into the chaincase from your case drain on the motor. If your filter is blocked it will cause a pressure build up and force fluid into the chaincase past the seal. Even with just normal wear, they will eventually leak.
I'd start there.

 

[jinxie]

Check your case drain filters to ensure they are not blocked.
If you pull the motors out, you will notice a big black seal on a shaft going into the chain case. If this is damaged oil will flow into the chaincase from your case drain on the motor. If your filter is blocked it will cause a pressure build up and force fluid into the chaincase past the seal. Even with just normal wear, they will eventually leak.
I'd start there.

Thanks Where are the case drain filters located?

 

[Tazza]

Thanks Where are the case drain filters located?

They will be in line from the small hose on the drive motors. One will be close to the motor, the other will be further along, possibly connected to the underside of the oil tank.
They are about 2" diameter and 4" long. They are a brass filter, you can clean them out. You may still need to replace the big seal in the motor carrier though. Its not that hard, but its easier with a tool to seat it.

 

[jinxie]

They will be in line from the small hose on the drive motors. One will be close to the motor, the other will be further along, possibly connected to the underside of the oil tank.
They are about 2" diameter and 4" long. They are a brass filter, you can clean them out. You may still need to replace the big seal in the motor carrier though. Its not that hard, but its easier with a tool to seat it.

Ok, here is a dumb question.... Do I need to drain the chaincase oil to replace the seals? It doesnt actually say to do so in the manual. We are expecting 15cm of snow tonight, so I have to use it as is for now. I am going to drain down the chaincase through the fill/level plug, then top off the hydraulic tank. I should be OK for the 1-2 hours it will take to clear my driveway.

 

[Tazza]

Ok, here is a dumb question.... Do I need to drain the chaincase oil to replace the seals? It doesnt actually say to do so in the manual. We are expecting 15cm of snow tonight, so I have to use it as is for now. I am going to drain down the chaincase through the fill/level plug, then top off the hydraulic tank. I should be OK for the 1-2 hours it will take to clear my driveway.

You will lose some oil out of the motor carrier when the seal is removed. But not a river. You could jack one side up higher than the other and work from side to side. You won't drain all the oil without the seal in place, but some will be lost.

 

[jinxie]

You will lose some oil out of the motor carrier when the seal is removed. But not a river. You could jack one side up higher than the other and work from side to side. You won't drain all the oil without the seal in place, but some will be lost.

Ok, finally getting ready to do this job. (Bobcat is just used for snow in the winter) 1) What size are the lines going to the travel motors? #20? They are 1 3/8" fittings. I assume the hydraulic oil will drain once the hoses are removed. I plan on buying caps. Looks like I will have fun getting the upper drive motor hose off. Any suggestions? How do you get a 1 3/8" wrench to fit?? Thanks

 

[Tazza]

Ok, finally getting ready to do this job. (Bobcat is just used for snow in the winter) 1) What size are the lines going to the travel motors? #20? They are 1 3/8" fittings. I assume the hydraulic oil will drain once the hoses are removed. I plan on buying caps. Looks like I will have fun getting the upper drive motor hose off. Any suggestions? How do you get a 1 3/8" wrench to fit?? Thanks

I'm not sure what size the ORFS fittings are, simple plugs or caps will hold back most of the oil, if you haven't changed your oil, it wouldn't hurt to let it drain and re-fill your tank. The hses aren't that bad to access actually. Start at the front, mark them with a centre punch so you know what one goes to what fitting, or it may turn the wrong way. Start at the front and work back (naturally) its really not hard to do. The hoses are really quite stiff, but hopefully they have formed their shape and will be easy enough to re-attach later.
Keep the motor clean! the rest really isn't that complicated. You can grab a copy of the service manual where OldMachinist has hosted them. It will show you exactly what is needed to be done. A 753/751 manual will both cover your machines drive setup.

 

[jinxie]

I'm not sure what size the ORFS fittings are, simple plugs or caps will hold back most of the oil, if you haven't changed your oil, it wouldn't hurt to let it drain and re-fill your tank. The hses aren't that bad to access actually. Start at the front, mark them with a centre punch so you know what one goes to what fitting, or it may turn the wrong way. Start at the front and work back (naturally) its really not hard to do. The hoses are really quite stiff, but hopefully they have formed their shape and will be easy enough to re-attach later.
Keep the motor clean! the rest really isn't that complicated. You can grab a copy of the service manual where OldMachinist has hosted them. It will show you exactly what is needed to be done. A 753/751 manual will both cover your machines drive setup.

Ok, so I am slow getting to this, but I finally have the travel motor out. Just to confirm, it is the motor located behind the cover between the 2 wheels on each side. It has 2 #14 hoses and 1 #6 case drain. I removed the 4 bolts and took the motor out. Next, I removed the seal carrier. It looks as though it has the 2 seals that faces opposite. There is also a large o-ring on the motor and another that seals the perimter of the seal carrier. The part that I dont get is that I explained to the dealer what I was doing. He sold me the large o ring that goes on the motor, BUT only 1 large seal (per side) that looks like a huge axle seal or something. No o-ring for the carrier and no 2 seals to go in the carrier. The seal he sold me is p/n 6705847. This isnt an update is it? I would still have a groove where the other oring is supposed to go. I am re-sealing the correct part that leaks hydraulic oil into the chaincase arent I? Thanks

 

[Tazza]

Ok, so I am slow getting to this, but I finally have the travel motor out. Just to confirm, it is the motor located behind the cover between the 2 wheels on each side. It has 2 #14 hoses and 1 #6 case drain. I removed the 4 bolts and took the motor out. Next, I removed the seal carrier. It looks as though it has the 2 seals that faces opposite. There is also a large o-ring on the motor and another that seals the perimter of the seal carrier. The part that I dont get is that I explained to the dealer what I was doing. He sold me the large o ring that goes on the motor, BUT only 1 large seal (per side) that looks like a huge axle seal or something. No o-ring for the carrier and no 2 seals to go in the carrier. The seal he sold me is p/n 6705847. This isnt an update is it? I would still have a groove where the other oring is supposed to go. I am re-sealing the correct part that leaks hydraulic oil into the chaincase arent I? Thanks

The seal that you want does look like a big axle seal.
Remove the motor and you will see a thin O ring that runs around the groove on the outside of the carrier. Replace this and the black seal on the shaft. I doubt the groove would be bad enough to leak when you replace it.