753 Skidsteer

Help Support SkidSteer Forum:

kjesa

New member
Joined
Jan 31, 2008
Messages
4
I have a hydraulic problem. Hydraulic fluid gets into the transmission case. I put new seals and orings in the drive motor axle. This seemed to help. Then when I attached my backhoe fluid disappeared again. I am really confused. Is there some place the hydraulic fluid can get into the trans case?
 

Tazza

Moderator
Staff member
Joined
Dec 7, 2004
Messages
16,844
The only way it can get in the chain case is through the motors seals on the shaft. Did you replace the seals in the motors or just the seal on the housing to the gearbox on machine?
 
OP
OP
K

kjesa

New member
Joined
Jan 31, 2008
Messages
4
The only way it can get in the chain case is through the motors seals on the shaft. Did you replace the seals in the motors or just the seal on the housing to the gearbox on machine?
Excuse me for my expertise, I replaced seal #6705847 and three orings. This I did on both sides. I didn't open the motor. I just removed the motor removed the seal and replaced new o-rings. My local Bobcat dealer (I live in Hawaii) they didn't have a clue. This forum is terrific I wish I had known about it earlier.
 

Tazza

Moderator
Staff member
Joined
Dec 7, 2004
Messages
16,844
Excuse me for my expertise, I replaced seal #6705847 and three orings. This I did on both sides. I didn't open the motor. I just removed the motor removed the seal and replaced new o-rings. My local Bobcat dealer (I live in Hawaii) they didn't have a clue. This forum is terrific I wish I had known about it earlier.
I assume this kit included the O-ring that sat inside the end of the motor where the shaft comes out of. From memory this should only be under charge pressure and is the main cause of leaks.
You may want to check your case drain filters as they could be blocked causing excessive pressure and causing it to leak into the chain case.
I have never pulled the motors off a 753 but essentially they are the same setup as the ones i have done before and it was a hard O-ring inside the motor housing where the shaft comes out. You can access this without pulling the motor down too.
I don't have my parts manual yet so i can't look up that seal kit...
 
OP
OP
K

kjesa

New member
Joined
Jan 31, 2008
Messages
4
I assume this kit included the O-ring that sat inside the end of the motor where the shaft comes out of. From memory this should only be under charge pressure and is the main cause of leaks.
You may want to check your case drain filters as they could be blocked causing excessive pressure and causing it to leak into the chain case.
I have never pulled the motors off a 753 but essentially they are the same setup as the ones i have done before and it was a hard O-ring inside the motor housing where the shaft comes out. You can access this without pulling the motor down too.
I don't have my parts manual yet so i can't look up that seal kit...
I think I replaced all the o-rings available. I had thought Bobcat would have a kit, but when I went to them the parts guy wasn't even sure what he was looking for. If you know of a kit please let me know. I discovered Bobcat has two seals for this machine. A plastic two part and a insulated coated one piece. I didn't know they had two different seals. The one I received was steel. I don't know if this effects anything. I can't for the life of me, other then construction, the steel would not work. If you have an opinion I would very much appreciate hearing. Do you know what the hydraulic pressure should be on this machine? Thank you very much for your assistance.
 

Tazza

Moderator
Staff member
Joined
Dec 7, 2004
Messages
16,844
I think I replaced all the o-rings available. I had thought Bobcat would have a kit, but when I went to them the parts guy wasn't even sure what he was looking for. If you know of a kit please let me know. I discovered Bobcat has two seals for this machine. A plastic two part and a insulated coated one piece. I didn't know they had two different seals. The one I received was steel. I don't know if this effects anything. I can't for the life of me, other then construction, the steel would not work. If you have an opinion I would very much appreciate hearing. Do you know what the hydraulic pressure should be on this machine? Thank you very much for your assistance.
Main hydraulic pressure should be around 2,400 and 2,600 PSI i'm not sure on the exact number but this should be very close. Charge pressure should be around the 200PSI mark.
I don't have my parts book yet so i can't tell you the seal numbers sorry. The seal you replaced, this sounds like the seal to the gear box and not the motor.. Did you replace an O-ring in the end of the motor where the shaft comes out of? it should have been around 1 1/2" diameter.
 
Top