873 Drive Motor Question

[wd2011]

I just finished all 4 axles with bearings, races, seals, even had to go with one new axle, sprocket, and hub assembly. I thought I was all done, and got everything covered up. I filled up the chaincase and the next morning I have a pool of oil on the floor. It is leaking all the way down the belly. I am suspecting the drive motor carrier seals to the chaincase to be shot, which I should have expected beforehand.
I don't want to invest in rebuilding the drive motors at this point since I am not having problems out of them. And correct me if I am wrong, I shouldn't have to pull the motor carriers when the motors fail in the future? My question though, since I essentially will be taking the motor assembly apart to get the carriers out are there any obvious parts I should go ahead and plan to replace, except for the front axle seals that I will have to replace again to drop the front chains? I was thinking more like seals that are easily accessible while getting at the motor carrier. Any info and or advice would be much appreciated. Thanks again!

 

[Tazza]

The carrier stays on the machine. The seal can be replaced without removing it, just take the motor off.
You will need to locate where the leak is coming from, if the motor is leaking and has excessive back pressure it will push past the seal and into the chain case, not leak outside unless the chain case is over filled. If its doing this, check your case drain filters, if they are plugged the back pressure will push past the seal and into the chain case.
If you need to remove the carrier, you just cut the chain and install master links or con-links. No need to loosen the axles.
Did you fill the chaincase to the correct level? to the bottom of the threads of the plug at the front?

 

[wd2011]

The carrier stays on the machine. The seal can be replaced without removing it, just take the motor off.
You will need to locate where the leak is coming from, if the motor is leaking and has excessive back pressure it will push past the seal and into the chain case, not leak outside unless the chain case is over filled. If its doing this, check your case drain filters, if they are plugged the back pressure will push past the seal and into the chain case.
If you need to remove the carrier, you just cut the chain and install master links or con-links. No need to loosen the axles.
Did you fill the chaincase to the correct level? to the bottom of the threads of the plug at the front?

I did fill it to the bottom of the threads on the plug in front, 10 gallons. I also should mention that the machine was not run at all in between the time we filled the chaincase and the time I noticed the leak, overnight. My first thought was the drain plug, but I RTV siliconed it when I put it in, and I also couldn't see how that could cause leaks from the belly up toward the front of the machine. We still have it torn apart with the cab off. So the leak is coming from a non-pressurized scenario, and is leaking while it is still up on jack stands.
Is there not a seal/gasket between the motor carrier and side of the chaincase? I assumed this based on logic and the fact that the only real place I thought I could see oil leaking out of is right under the motor carrier agaist the chaincase, mind you I haven't got a great look at it yet due to the limited clearance underneath the carrier and the belly.

 

[Tazza]

I did fill it to the bottom of the threads on the plug in front, 10 gallons. I also should mention that the machine was not run at all in between the time we filled the chaincase and the time I noticed the leak, overnight. My first thought was the drain plug, but I RTV siliconed it when I put it in, and I also couldn't see how that could cause leaks from the belly up toward the front of the machine. We still have it torn apart with the cab off. So the leak is coming from a non-pressurized scenario, and is leaking while it is still up on jack stands.
Is there not a seal/gasket between the motor carrier and side of the chaincase? I assumed this based on logic and the fact that the only real place I thought I could see oil leaking out of is right under the motor carrier agaist the chaincase, mind you I haven't got a great look at it yet due to the limited clearance underneath the carrier and the belly.

There is a gasket around the carrier, i assumed it was not leaking before but you did mention that the leak was why you replaced the axle seals.
If you give it a good clean, it will help you work out where the leak is coming from. If you're lucky if you can tighten the mounting bolts a little it could stop the leak, if it is really coming from the carrier. Sadly they are hard to access and meant to be really tight.

 

[wd2011]

There is a gasket around the carrier, i assumed it was not leaking before but you did mention that the leak was why you replaced the axle seals.
If you give it a good clean, it will help you work out where the leak is coming from. If you're lucky if you can tighten the mounting bolts a little it could stop the leak, if it is really coming from the carrier. Sadly they are hard to access and meant to be really tight.

Yeah that has to be where the oil is coming from. It is definitely chaincase oil. So let me tell you my plan to replace the gasket between the carrier and chaincase and let me know if you think it will work.
I am going to break the chains, I just ordered a good chain breaker tool, where can I get the master links from? The specs for the chain in the manual say #100 chain. If I just find a master link for ANSI #100 is that what I need? Perhaps you could suggest one so I can see what I need to look for. After breaking the chain I will disconnect the hydraulic lines from the motor. Unbolt the carrier from the chaincase and slide the motor and carrier assembly as far to the side of the machine as possible. Then I will pull the gasket off and out through the chaincase, then install the new one in reverse. Then slide the motor assembly back in place and get everything back together. I was hoping since I just need to replace that gasket that I can avoid removing the motor and carrier from the machine completely. Let me know if you think that plan could work. Thanks again for your advice!

 

[Tazza]

Yeah that has to be where the oil is coming from. It is definitely chaincase oil. So let me tell you my plan to replace the gasket between the carrier and chaincase and let me know if you think it will work.
I am going to break the chains, I just ordered a good chain breaker tool, where can I get the master links from? The specs for the chain in the manual say #100 chain. If I just find a master link for ANSI #100 is that what I need? Perhaps you could suggest one so I can see what I need to look for. After breaking the chain I will disconnect the hydraulic lines from the motor. Unbolt the carrier from the chaincase and slide the motor and carrier assembly as far to the side of the machine as possible. Then I will pull the gasket off and out through the chaincase, then install the new one in reverse. Then slide the motor assembly back in place and get everything back together. I was hoping since I just need to replace that gasket that I can avoid removing the motor and carrier from the machine completely. Let me know if you think that plan could work. Thanks again for your advice!

You will need to drain the oil first, as the bolt holes are rather low. You will need to remove the drive motor, i doubt you will have enough space to slide the carrier and motor to the side and get the new gasket in place. Personally, i would take the old one off, get some automotive silicone and coat the gasket with glue and put it in place. I did this on a 751 that i had the carriers off, it didn't leak a drop. The thing you need to keep in mind if you do it this way is to get the carrier in place and chains on pretty fast. You need to adjust the end to end location so the slack in the chains is the same front and back.
Master links can be bought from most bearing shops, or at least they can get them in for you. Not sure what one you need, i don't fully understand the way the measure chain.

 

[wd2011]

You will need to drain the oil first, as the bolt holes are rather low. You will need to remove the drive motor, i doubt you will have enough space to slide the carrier and motor to the side and get the new gasket in place. Personally, i would take the old one off, get some automotive silicone and coat the gasket with glue and put it in place. I did this on a 751 that i had the carriers off, it didn't leak a drop. The thing you need to keep in mind if you do it this way is to get the carrier in place and chains on pretty fast. You need to adjust the end to end location so the slack in the chains is the same front and back.
Master links can be bought from most bearing shops, or at least they can get them in for you. Not sure what one you need, i don't fully understand the way the measure chain.

Thanks again for your info. Interestingly enough Bobcat stopped making a gasket for between the carriers and the chaincase. They have gone to the liquid gasket now. So I will do as you suggested and just silicone it up.
As for the chain connecting link the manual says #100 HS roller chain so I ordered the size 100 connecting link for Heavy Series roller chain from loaderpartssource. That should take care of it and I am looking forward to another fun filled weekend in the belly of this beast.

 

[Tazza]

Thanks again for your info. Interestingly enough Bobcat stopped making a gasket for between the carriers and the chaincase. They have gone to the liquid gasket now. So I will do as you suggested and just silicone it up.
As for the chain connecting link the manual says #100 HS roller chain so I ordered the size 100 connecting link for Heavy Series roller chain from loaderpartssource. That should take care of it and I am looking forward to another fun filled weekend in the belly of this beast.

Silicone will be much cheaper too. I think it will give a better seal too.
I hope this time round it fixes the leak once and for all.

 

[mrdeere1959]

Silicone will be much cheaper too. I think it will give a better seal too.
I hope this time round it fixes the leak once and for all.

We have been using a permatex product that works really well its a gasket eliminator in a "cheese whiz" can, its called right stuff gasket maker. its easier to use then silicon.

 

[siduramaxde]

We have been using a permatex product that works really well its a gasket eliminator in a "cheese whiz" can, its called right stuff gasket maker. its easier to use then silicon.

I also use the stuff in the "cheese whiz" can. It works great. When your done with the project your using it on you just leave a bit of the silicone hang out of the tip. When you need it next time you just pull off the dried material and fresh silicone will come right out. Much better than the stuff in the tubes.

 

[Fishfiles]

I also use the stuff in the "cheese whiz" can. It works great. When your done with the project your using it on you just leave a bit of the silicone hang out of the tip. When you need it next time you just pull off the dried material and fresh silicone will come right out. Much better than the stuff in the tubes.

I have some cheeze whiz gasket maker and it does work very well , a while back I did a job on a Komatsu and they told me the front 4x4 planetary gasket was no longer available for that model and they sold me a tube of stuff you put in a chaulking gun , I was looking at it the other day and never really read the label when I first used it , it said it was some kind of glass adhisive and it is black and gets really hard --------------what I use the most is the Perma-tex red , I am not sure of the spelling of this word , "anarobic" gasket eliminator , it doesn't get hard till it is absent of air , which amazes me as it is absent of air when it is in the tube , but never gats hard in the tube or the tip ----------------

 

[Tazza]

I have some cheeze whiz gasket maker and it does work very well , a while back I did a job on a Komatsu and they told me the front 4x4 planetary gasket was no longer available for that model and they sold me a tube of stuff you put in a chaulking gun , I was looking at it the other day and never really read the label when I first used it , it said it was some kind of glass adhisive and it is black and gets really hard --------------what I use the most is the Perma-tex red , I am not sure of the spelling of this word , "anarobic" gasket eliminator , it doesn't get hard till it is absent of air , which amazes me as it is absent of air when it is in the tube , but never gats hard in the tube or the tip ----------------

It sounds like it works like loctite and super glue does, they both work in the absense of air too.
Amazing stuff.