743 rear axle leaking oil

[OLE4]

After a few hours of use today I noticed that one of the rear wheels had oil all over it. When I got the machine I had cleaned out chaincase which was a bit low and refilled to correct level, seems it is leaking out of axle seal. Read the manual and they say to remove chain but I am not sure why, can't I remove axle bolt and pull axle just let sprocket fall off? Anyone ever change the seal? I guess once it is out I should replace the bearings as well correct. How hard is it to pull the axle out?? They also show a installation tool to prevent driving the axle in too far I guess that is available at bobcat? If anyone has done this can you give me a heads up on the difficulties you encountered? For now I will just keep cleaning it Thanks Ole

 

[Tazza]

The rear seals are a big job. As you stated, you can remove the bolt and pull the axle out, but gaining access is not fun. You really need the rear inspaction plate off, which is under the drive pump.
Before you start, grab the axle hub and pull it in and out, if it moves a lot, you will need bearings, if not, they should be ok if you can remove the outer one without damage. If it does, just replace the one. If they look worn, change them out of course, if they look good, i'd re-use them.
The seal installation tool does push the seal in to the correct depth, but i have also had success with using an old bearing cup cut in half then i put it over the axle and used a hose clamp to hold it in place. Then hit the rear of the axle to get it to seat. Its pretty close to the right size to make it seat in just the right amount. Check the space on the other axles to confirm your axle is machined the same so that this trick will give the correct depth.
The axles should have no end float, this can be removed by machining some off the washer on the end of the axle, if you leave a step it will pull the axle in that little bit more. The chaincase i just did needed 3 of them doing, one was right, all got new bearings.
Good luck

 

[OLE4]

The rear seals are a big job. As you stated, you can remove the bolt and pull the axle out, but gaining access is not fun. You really need the rear inspaction plate off, which is under the drive pump.
Before you start, grab the axle hub and pull it in and out, if it moves a lot, you will need bearings, if not, they should be ok if you can remove the outer one without damage. If it does, just replace the one. If they look worn, change them out of course, if they look good, i'd re-use them.
The seal installation tool does push the seal in to the correct depth, but i have also had success with using an old bearing cup cut in half then i put it over the axle and used a hose clamp to hold it in place. Then hit the rear of the axle to get it to seat. Its pretty close to the right size to make it seat in just the right amount. Check the space on the other axles to confirm your axle is machined the same so that this trick will give the correct depth.
The axles should have no end float, this can be removed by machining some off the washer on the end of the axle, if you leave a step it will pull the axle in that little bit more. The chaincase i just did needed 3 of them doing, one was right, all got new bearings.
Good luck

Tazza isnt it just one big cover over the chaincase? When I cleaned out the chaincase the cover covered the whole thing and did go under the pump up to the front and had the brake assembly as well. Is that the cover you are talking about? How big a impact puller do I need to pull axle? I do have a hydraulic floor press so I can get bearings off axle without their special puller. Ole

 

[Tazza]

Tazza isnt it just one big cover over the chaincase? When I cleaned out the chaincase the cover covered the whole thing and did go under the pump up to the front and had the brake assembly as well. Is that the cover you are talking about? How big a impact puller do I need to pull axle? I do have a hydraulic floor press so I can get bearings off axle without their special puller. Ole

There are two plates, the brake assembily and the one that the pedal mounts to. It seems you got them both off, so hopefully you can gain access.
With the bolt on the inside of the chaincase off (1 1/8”) i use a bottle jack. Sit it on its side with the pump at the bottom, pump it behind the axle hub and it will pull the axle out. You don't really need that much pressure to get them out. The press will help with pulling and replacing the bearing, thats for sure.
Its really quite easy, the hardest bit is putting the sprocket back on. You have to put the bearing in, lift the sprocket, get another person to push the axle in and rotate to get it to engage. When its in place, you use the bolt to pull the bearing into place. With a spanner on the bolt, you can slowly engage your drive and tighten the bolt. Get it tight and check for end float. If its ok, remove the bolt, clean the threads and put loctite on it, tighten it up.
Hopefully that gives you an idea of how to go about it. I did a chaincase for a friend about 3 weeks ago, it was sad, all the bearings and seals were shot, including the reduction boxes....

 

[OLE4]

There are two plates, the brake assembily and the one that the pedal mounts to. It seems you got them both off, so hopefully you can gain access.
With the bolt on the inside of the chaincase off (1 1/8”) i use a bottle jack. Sit it on its side with the pump at the bottom, pump it behind the axle hub and it will pull the axle out. You don't really need that much pressure to get them out. The press will help with pulling and replacing the bearing, thats for sure.
Its really quite easy, the hardest bit is putting the sprocket back on. You have to put the bearing in, lift the sprocket, get another person to push the axle in and rotate to get it to engage. When its in place, you use the bolt to pull the bearing into place. With a spanner on the bolt, you can slowly engage your drive and tighten the bolt. Get it tight and check for end float. If its ok, remove the bolt, clean the threads and put loctite on it, tighten it up.
Hopefully that gives you an idea of how to go about it. I did a chaincase for a friend about 3 weeks ago, it was sad, all the bearings and seals were shot, including the reduction boxes....

You are correct one cover had a flange where it went over the other cover Thanks for the info.

 

[OLE4]

You are correct one cover had a flange where it went over the other cover Thanks for the info.

pulled the wheel off the leaking side cleaned it up and found a long string wound around the axle up against the seal. I removed all of it and recleaned all around the seal and do not see any damage, not sure if I lucked out or if the string ruined the seal. so far no oil has come out but I probably need to run it some to see.

 

[Tazza]

pulled the wheel off the leaking side cleaned it up and found a long string wound around the axle up against the seal. I removed all of it and recleaned all around the seal and do not see any damage, not sure if I lucked out or if the string ruined the seal. so far no oil has come out but I probably need to run it some to see.

*fingers crossed* Hopefully you will be lucky.

 

[OLE4]

*fingers crossed* Hopefully you will be lucky.

lucked out after removing string and cleaning ran it for at least an hour and seal is dry Hooray!!!