T190 Bobcat Hydraulic Track Drive Motors Leaking

[hotrod45]

I just had a track fail on my T190 Bobcat. The Hydraulic drive motor bearing oil seal is leaking. Can this seal be replaced by myself? I have heard of people injecting grease into the bearing instead of the gear oil. Is using grease a worthwhile endeavor and if so how do you fill the cavity with grease? Thanks for your replies.

 

[Vetech63]

Are you talking about the motor shaft seal? Grease filling isn’t going to fix that, the oil will just push it out.

 

[ozarkag]

I assume your drive motor face seal is leaking oil. These only hold 4 Oz of oil, so a typical seal failure may go unnoticed for years. The bearing will survive surprisingly long, unlike a planetary drive unit.
My question is, what happened, or what has failed.

To answer your questions,
You can change a seal yourself,  if you are an experienced mechanic, with a working knowledge of hydro internals.
Yes, grease fill works very well in these, i have used deeres corn head gease in particular.
You need to remove the track and the sprocket to access the oil fill and drain plugs.

 

[hotrod45]

I assume your drive motor face seal is leaking oil. These only hold 4 Oz of oil, so a typical seal failure may go unnoticed for years. The bearing will survive surprisingly long, unlike a planetary drive unit.
My question is, what happened, or what has failed.

To answer your questions,
You can change a seal yourself,  if you are an experienced mechanic, with a working knowledge of hydro internals.
Yes, grease fill works very well in these, i have used deeres corn head gease in particular.
You need to remove the track and the sprocket to access the oil fill and drain plugs.

Yes that is what's leaking. The track was worn and broke on turning. Last year I replaced the oil and I noticed the seal leaks a fair amount. Can the seal be replaced without disassembling the hydraulic motor. I am a journeyman automotive mechanic and have dome some heavy equipment repairs but never worked on a hydraulic drive motor. So you arecsaying that grease is an option. If so do you pump it in through the oil fill bung?

 

[willie59]

I'll offer a different line of thinking. Those motors are notorious for catastrophic failure after many hours of service. And when they do that they inject substantial metal debris in the hydraulic system, especially the hydrostat drive pumps which don't like debris. Yes, I know that's the motor, not the seal that you're referring to. I'm only saying, a motor main seal lasts for years of service, even under extreme conditions. The fact that it's now leaking simply means that motor has many hours on it. For that reason alone I'd be just as suspicious of the motor internals. Yes, they cost coin, but if you can shake it, I'd consider replacing those motors from someone like Loader Parts Source, they're typically a little bit less than OEM Bobcat, I've fitted a number of them with no issue. Just thought I'd throw that out there to consider.

 

[hotrod45]

I assume your drive motor face seal is leaking oil. These only hold 4 Oz of oil, so a typical seal failure may go unnoticed for years. The bearing will survive surprisingly long, unlike a planetary drive unit.
My question is, what happened, or what has failed.

To answer your questions,
You can change a seal yourself,  if you are an experienced mechanic, with a working knowledge of hydro internals.
Yes, grease fill works very well in these, i have used deeres corn head gease in particular.
You need to remove the track and the sprocket to access the oil fill and drain plugs.

I have rebuilt many automatic transmissions. Would rebuilding one of these hydraulic be much different if you have a manual with all the specs and the tools to do it? Thanks.

 

[HarleyHappy]

The only issue with rebuilding, from my experience, is that the parts are very expensive. I had my CharLynn drive motor pop the oil seal and just the seal kit was 200 dollars and the shaft and bearing, one piece, was 1800 dollars. I was able to source a non-branded drive for 900 dollars.
I didn’t want to take the chance of having more debris from the worn drive going through the pumps any more than necessary.

 

[ozarkag]

check CR Components for seal and parts. Complete drives from there, or new, (not reman) from Final Drive Motors.
Grease is an option, but only a patch, not a permanent fix. Would go in thru the outer bearing oil fill bung.

If it is leaking actual hydraulic oil, not just the 4 oz of gear oil, you will most likely need to replace the final drive. If you are seeing a steady leak it is most likely hydraulic oil, meaning the shaft seal is also leaking.

 

[hotrod45]

check CR Components for seal and parts. Complete drives from there, or new, (not reman) from Final Drive Motors.
Grease is an option, but only a patch, not a permanent fix. Would go in thru the outer bearing oil fill bung.

If it is leaking actual hydraulic oil, not just the 4 oz of gear oil, you will most likely need to replace the final drive. If you are seeing a steady leak it is most likely hydraulic oil, meaning the shaft seal is also leaking.

Thanks Ozarkag. You mention not to get reman drives from Final Drive Motors. Are there reman drives not rebuilt well or are all reman drives from any manufacturer not good?

 

[Tones]

Usually it high casedrain oil pressure that causes the seal to fail. At the very least a new rotating group in the motor is required.

 

[hotrod45]

Usually it high casedrain oil pressure that causes the seal to fail. At the very least a new rotating group in the motor is required.

The seal I am referring to is the seal that is against the sprocket. I don't think there is pressurized fluid on that seal but only synthetic gear oil or am I mistaken.

 

[willie59]

You need to remove the case drain filter for that final that,s leaking, take it apart and see if there's metal debris inside the filter. If there is, replace the final drive.

 

[ozarkag]

Thanks Ozarkag. You mention not to get reman drives from Final Drive Motors. Are there reman drives not rebuilt well or are all reman drives from any manufacturer not good?

Sorry, that wasn't quite clear. Final Drive Motors is one of the only places that sells aftermarket all new drives, versus the more common reman units.

 

[hotrod45]

Has anyone ever bought or heard of someone buying a Chinese made final drive? Just wondering how good they are? I'll bet most brand names have their parts made in China anyway?

 

[Tones]

Hotrod you need to get your terminology correct. First it's a hydraulic motor failure, now a planetary hub failure, 2 different things.

 

[hotrod45]

Oh sorry. When I looked at the reman parts they list them as final drives for the T190.

 

[ozarkag]

Hotrod you need to get your terminology correct. First it's a hydraulic motor failure, now a planetary hub failure, 2 different things.

Sort of. . . But not really on CTLs, it is a one piece unit. Final drive includes hydraulic motor all in one.

 

[Tones]

Sort of. . . But not really on CTLs, it is a one piece unit. Final drive includes hydraulic motor all in one.

I understand that but the facts are they are 2 components which owners need to understand, kinda like an engine losing power because a bearing has seized in a gearbox.

 

[willie59]

The Bobcat T190 final drive doesn't have planetary gears like found on excavator final drives, it's a unit motor/drive that incorporates a roller piston motor to rotate the output shaft all in a single housing unit. When they fail, it's typically the rollers or the roller cam plate wear out, piston comes out of their bores and fill the bearing housing with pressure along with metal from failed rollers/cam, that's what clogs the case drain filters. As I noted previously, check your case drain filters. When this case pressure happens, along with clogged case drain filter, it forces oil through the output shaft seal. Check you case drain filter for signs of metal debris.

 

[hotrod45]

Thanks for replying willie59. I replaced the case drain filters last fall. There was virtually no metal in them. The outer seals were leaking then. I drained and put new oil in the bearing cavity. I am wondering if you have herd reviews on the Chinese made motor/drives? I am thinking about buying one new motor and then rebuilding the other ones myself.