My 732 has been leaking what appears to be hydraulic fluid through one of the rear axle seals. At first, I thought it was just running off the axle tube from inside the machine, but it turns out to actually be coming through the axle seal,so my question is? Is the gearbox supposed to be part of the hydraulic resivoir system and the problem just the seal? Or is there something more amiss, as I suspect maybe one of the wheel motors may be dumping hydraulic into the gearbox thereby overfilling it and pushing the fluid out through the axle? sorry, seems like kind of a dumb question, but I have no owners or service manual so I am in the dark on how some of these systems work. It looks like getting to the axle seal will require a major teardown so if anyone has any advice, I would certainly appreciate it. Thanks
732 axle leak
- Thread starter schmelvy
- Start date
If your hydraulic fluid level goes down, it sounds like the seal on the reduction box is bad.
Axle seals do fail too, sadly the rear ones are the hardest to do.... You really need to pull the engine out and un-mount the pump and lift it up to get into the inspection cover. Even pulling the pump out will give you heaps of space.
Axle seals do fail too, sadly the rear ones are the hardest to do.... You really need to pull the engine out and un-mount the pump and lift it up to get into the inspection cover. Even pulling the pump out will give you heaps of space.
OK, thank you. The hydraulic fluid level does drop due to the axle leak. is the reduction box is the unit the wheel motor is attached to? any thoughts on getting at that?
Yes, the reduction box is the part that the motor bolts to. If you take the motor off, you should be able to see the main seal that stops fluid going from the motor to the chain case.
thank you again, I will pull the motors off and try to see which one is leaking. Is there anything I need to be aware of before pulling the motors? It looks pretty straightforward.
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They are pretty simple, 3 hoses and 4 bolts, the motor slides out.
Not easy to tell from looking at the seal to know what one is bad, generally you just replace both then you know you got it.
Drill a small hole in the seal and screw in a self tapping screw and use pliers to pull it out.
ok, after deciding I was too busy to deal with the old bobcat for the summer, I finally pulled off the wheel motors today. It does look like the seals are leaking a little, but my question is this: is the hydraulic fluid in that cavity static or is it under pressure from the motor? It sure doesn't seem like that much fluid would be blowing past the seal if it wasn't under at least some pressure. so, with that being said, do I need to get the wheel motors checked? What I mean is: could one of the wheel motors have something wrong with it that would put an excessive amount of hydraulic in that cavity thereby forcing the fluid past the seal? just tell me if I am over thinking this. maybe It is as simple as replacing the seals. Thank you.
There will be a little pressure there, not much at all. Where the dog bone shaped part of the motor sticks out, this area leaks fluid that goes back to the oil tank. I can't remember if it's under charge pressure or not though, if it is, it has 110PSI behind it. I'd like to think it had no pressure though.
I don't think you will need to get the motors looked at if it has a shaft that wobles around, if it had a straight shaft with a seal then yes.
sounds good, it is the motor with the wobble shaft so that should be ok. I now have everything cleaned up and the seals so I am ready to put it back together. My next question is this- because the gear cases and chain case are basically full of hydraulic oil at this point due to the leaky seals,(and I am guessing they should be filled with gear lube) how do you drain it? is there a drain/ fill procedure anywhere you can point me to? and as long as we are on the subject, what is the correct lube for the chain case and gear cases? thanks for all your help
It should be filled with the same fluid as the hydraulic system, so 20w50 etc. If it's not milky, just remove the plug at the front of the chain case and let it drain till it stops, while parked on flat ground. At this point the oil level is correct.
