Trouble with 743b Bobcat

hi guys i'm new here. My company recently purchase an old Bobcat 743-743B Bobcat. the model no. on the back of the track says 743 B but the decals are 743. I recently purchase a service manual for 743. The trouble is that the rear right side wheel is leaking with oil. plus. i recently replace the hydraulic oil since it is already milky white. After replacing the hyd oil. the arms aren't smooth enough to go up when engaging the hydraulic pump for the breaker. and there is a noise on the right side wheels when moving. Hope you guys can help. plus the breaker is really slow compared before changing the hyd oil.. how will i get rid of the air/ bleed the system. or did my pump already died on me? got trouble accessing the rear wheel since there's a lot to get rid off before accesing it under.

Ok, first off. Depending on how you drained the oil, you may need to swap it a few more times yet. The ideal way is to remove everything and drain the oil from it all, big job that i'm sure you didn't go to the trouble to do.Ensure the oil is nice and clean, no traces of white.
Air will take time to all purge. Mine took a few weeks of running for short periods of time and shutting off. It will happen eventually, just be patient.
The axle seal. Is there a bolt on the end of the axle hub? if so, the job is simple enough. If not, you have a standard 743 and not the B series that has two piece axles taht you can knock the hub off. Let me know if it has the bolt and we can go from there.

Tazza said:

Ok, first off. Depending on how you drained the oil, you may need to swap it a few more times yet. The ideal way is to remove everything and drain the oil from it all, big job that i'm sure you didn't go to the trouble to do.Ensure the oil is nice and clean, no traces of white.
Air will take time to all purge. Mine took a few weeks of running for short periods of time and shutting off. It will happen eventually, just be patient.
The axle seal. Is there a bolt on the end of the axle hub? if so, the job is simple enough. If not, you have a standard 743 and not the B series that has two piece axles taht you can knock the hub off. Let me know if it has the bolt and we can go from there.

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Well. We did drain the whole oil tank. not with the one running in and out the valves and hydraulic lines.. Whats the best possible thing to do to hasten the purge of the air circulating the lines. if i were to drain everything where should i start. for the axel hub. when we took out the tires i can't see any nut in the middle only a dot. looks like its a one piece axle. can the hydraulic oil filter do the job on cleaning the old oil circulating in the hydraulic lines?

I am reading in between the lines and you said that the boom is not smooth going up with the breaker engaging the hydraulic pump , are you engaging the aux with the detent while trying to operate the machine cause it will cause the boom to act funny as it is diverting the oil to the aux ----------------best way i found to purge the air was to put the boom all the way up and work the tilt back and forth full stroke alot and then the boom up and down full cycle alot , then let it sit awhile then repeat the procedure as many times as needed

Fishfiles said:

I am reading in between the lines and you said that the boom is not smooth going up with the breaker engaging the hydraulic pump , are you engaging the aux with the detent while trying to operate the machine cause it will cause the boom to act funny as it is diverting the oil to the aux ----------------best way i found to purge the air was to put the boom all the way up and work the tilt back and forth full stroke alot and then the boom up and down full cycle alot , then let it sit awhile then repeat the procedure as many times as needed

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thanks guys for the fast reply on the trouble i had. will do what you guys ask. there is also another problem. remember i am leaking oil on the rear left wheel. the right side of the equipment is really really noisy. what could be the problem.. is it because the oil is leaking?

bluthunder said:

thanks guys for the fast reply on the trouble i had. will do what you guys ask. there is also another problem. remember i am leaking oil on the rear left wheel. the right side of the equipment is really really noisy. what could be the problem.. is it because the oil is leaking?

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Your wheel noise /leak problem is probally the seal is torn up and the oil is leaking out the chain case , and the bearings on the axle are bad is where the noise is coming from , lots of how to make thoses repairs on this site

Fishfiles said:

Your wheel noise /leak problem is probally the seal is torn up and the oil is leaking out the chain case , and the bearings on the axle are bad is where the noise is coming from , lots of how to make thoses repairs on this site

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The chain case is a seperate tank, so the leak here will not cause any problems with your hydraulics. As fishfiles said, lift the arms, operate tilt, drive around then let it sit for the air to settle out of the tank, repeat and it will eventually go and your lift/tilt and drive will be smooth again. It can take some time though, so don't be too worried if it takes a few days of doing this.
As you mention it has no bolt, it sounds like its a 743, not the B model. This is a rather large job to change the axle seal. You really need to pull the pump out for access then get a spanner inside the chaincase to un-do the bolt holding the sprocket on the axle, pull the axle and bearings out, install a new seal, check the wear ring, and replace the bearings if required.
If you go that far, do ALL four seals and mop the chain case out and replace the oil. Its a large job, but can be done.