743 , leaking chain oil

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miszka01

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Jan 27, 2007
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Somebody know how to change the simmering ( gasket) on main axle at bobcat 743. Simmering is permeable and oil is leaking. How to change that ? Please help
 

Tazza

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Ok, where exactly is the leak? is the chain case over filling? or is it just a bad axle seal? or just a simple gasket on the inspection covers on the top.
 
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miszka01

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Jan 27, 2007
Messages
13
Ok, where exactly is the leak? is the chain case over filling? or is it just a bad axle seal? or just a simple gasket on the inspection covers on the top.
Hello Tazza !! The simmering is permeable on axle. ( the tires are screw on axle) Oil is leaking by tires when bobcat is runining and stop, everytime
 

Tazza

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Hello Tazza !! The simmering is permeable on axle. ( the tires are screw on axle) Oil is leaking by tires when bobcat is runining and stop, everytime
Ok, so axle seals.
I take it you have just a 743 and not the 743B. Is there a bolt on the end of the axle where the tyres are bolted to? or is just welded on?
If its bolted you are in luck, remove the bolt, install a hydraulic bottle jack between the frame and axle hub with the pump section on the under side. Pump it up to get the axle housing off, screw a self tapping screw into the seal and pull it out, replace the seal and axle housing and you are set.
Now, if you don't have 2 piece axles the job just got MUCH harder. If this is the case i hope the problem is a front tyre, they are easier to gain access to. you will need to remove the plate that the steering levers come through, then the front inspection plate if you are doing the front and the rear one that holds the park brake if you are doing the rear. Now it gets hard!
Drain the oil, insert a 1 1/8" spanner inside the chain case to the end of the axle there is a bolt, this must be un-done. They are SUPER tight and held in with loctite. You have 2 options to un-do these, you can start the machine and get it to spin that side to un-do the bolt or you can remove the 2 large hoses from the hydro motor on that side and turn the axle with a bar. Install a jack between the frame and axle hub like mentioned earlier this will pull the seal and bearing out. Slide the axle out pull the bearing off, install a new wear ring and seal, re-install the bearing and grease it up, slide it back in, this is a 2 person job! slide the bearing on the end of the axle then lift and position the sprocket and get them to engage. You need an axle seal tool here but an old bearing cup cut in half will also work, slide it around the axle and hold with a hose clamp, belt the end of the axle till it seats correctly, remove the bearing cup and clamp. Install the bolt with loctite and tighten it really tight. Re-fill with oil and re-attach everything and you should be set.
I may have missed a few things there but its essentially all there. Now do note the sprockets are heavy and some teeth may be sharp and WILL cut you. The chain is also heavy, its not a fun job. If you can, use a chain breaker and the job will be much easier.
Good luck with it! its not easy but it can be done.
 
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miszka01

Member
Joined
Jan 27, 2007
Messages
13
Ok, so axle seals.
I take it you have just a 743 and not the 743B. Is there a bolt on the end of the axle where the tyres are bolted to? or is just welded on?
If its bolted you are in luck, remove the bolt, install a hydraulic bottle jack between the frame and axle hub with the pump section on the under side. Pump it up to get the axle housing off, screw a self tapping screw into the seal and pull it out, replace the seal and axle housing and you are set.
Now, if you don't have 2 piece axles the job just got MUCH harder. If this is the case i hope the problem is a front tyre, they are easier to gain access to. you will need to remove the plate that the steering levers come through, then the front inspection plate if you are doing the front and the rear one that holds the park brake if you are doing the rear. Now it gets hard!
Drain the oil, insert a 1 1/8" spanner inside the chain case to the end of the axle there is a bolt, this must be un-done. They are SUPER tight and held in with loctite. You have 2 options to un-do these, you can start the machine and get it to spin that side to un-do the bolt or you can remove the 2 large hoses from the hydro motor on that side and turn the axle with a bar. Install a jack between the frame and axle hub like mentioned earlier this will pull the seal and bearing out. Slide the axle out pull the bearing off, install a new wear ring and seal, re-install the bearing and grease it up, slide it back in, this is a 2 person job! slide the bearing on the end of the axle then lift and position the sprocket and get them to engage. You need an axle seal tool here but an old bearing cup cut in half will also work, slide it around the axle and hold with a hose clamp, belt the end of the axle till it seats correctly, remove the bearing cup and clamp. Install the bolt with loctite and tighten it really tight. Re-fill with oil and re-attach everything and you should be set.
I may have missed a few things there but its essentially all there. Now do note the sprockets are heavy and some teeth may be sharp and WILL cut you. The chain is also heavy, its not a fun job. If you can, use a chain breaker and the job will be much easier.
Good luck with it! its not easy but it can be done.
Thanks Tazza !!! :( The tyres just welded on axle
 

Tazza

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Thanks Tazza !!! :( The tyres just welded on axle
I thought they would be, that means you have to do it the hard way. It can still be done its just harder. Good luck with it though.
When you do this and drain the oil from the chain case, mop out all you can with a rag and replace the oil. Chances are it has never been done. It should be changed every 1000 hours to remove any metal particles from wear of the chain and sprockets.
 

Idoitall

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Mar 17, 2007
Messages
126
I thought they would be, that means you have to do it the hard way. It can still be done its just harder. Good luck with it though.
When you do this and drain the oil from the chain case, mop out all you can with a rag and replace the oil. Chances are it has never been done. It should be changed every 1000 hours to remove any metal particles from wear of the chain and sprockets.
As Tazza says, clean out the chain case good while in there. I also recall this from another post way back. Add a large magnet to the chain case. Seems like a great idea.

"All ya have to do is remove them from the speakers and they will work for ya real good and will stick to the sides. Ya can get speaker magnets at any stereo shop, just ask and they will point ya ta the dumpster, LOL"
 

Tazza

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As Tazza says, clean out the chain case good while in there. I also recall this from another post way back. Add a large magnet to the chain case. Seems like a great idea.

"All ya have to do is remove them from the speakers and they will work for ya real good and will stick to the sides. Ya can get speaker magnets at any stereo shop, just ask and they will point ya ta the dumpster, LOL"
I installed one from an old hard drive, they are the super powerful earth magnets, they are strong enough that if you have 2 and let them snap together and catch a bit of your finger they will give a nice size blood blister, don't ask how i know that......
emotion-7.gif
 

pondfishr

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Oct 11, 2005
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216
I installed one from an old hard drive, they are the super powerful earth magnets, they are strong enough that if you have 2 and let them snap together and catch a bit of your finger they will give a nice size blood blister, don't ask how i know that......
Where do you obtain a chain breaker as mentioned in this thread?
 

Tazza

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Where do you obtain a chain breaker as mentioned in this thread?
I'm not sure, but i believe any chain and sprocket shore should be able to help you out. Once you break the chain, you will need to install a link to repair the chain.
 

Tazza

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Thank you so much TAZZA for your scan. I'm going to fix bobcat :)
Good to hear, do let us know how you go!
I'm currently working with another member of the forum to replace his seals. You will most likely need to replace the bearing at the end of the axle as you will probably damage it when you pull the axle out of the axle tube and it takes the seal with it, use a hydraulic jack with the pump on the underside to remove the axle and seal, BUCH easier than the slide hammer shown in the scans.
You will need a 1 1/8" ring/open end spanner to crack the bolt on the end of the axle where the sprocket fits.
Good luck!
 

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