Bobcat 743B

[wbecker319]

Hi, new here, just bought a 743B, I have manuals on the way. I am missing the grill above the radiator, anyone have one or know where I should start looking? I'm in the St Louis area. How many hours does one of these Kubota engines run before overhaul? How long do the drive chains last? Any tips appreciated. Thanks, Bill

 

[OldMachinist]

The grill part number is 6567868 and still shows as available from Bobcat.
A well maintained Kubota engine is good for at least 5000 hours if not abused. A compression test will tell you a lot about it condition. V1702 compression should be 427-469 psi with no more than 50 psi difference between cylinders.
Drive chain life depends on how the machine has been used. Since you don't know when the chaincase oil was replaced last you should remove the front cover, check the oil and chains condition.
Lift the machine and block it up. Check each wheel for up-down and in-out play. Also look for oil seepage at the axle tube/flange area.

Check and grease the u-joints that connect the engine to the pumps. If they fail it will cause catastrophic damage.

 

[wbecker319]

The grill part number is 6567868 and still shows as available from Bobcat.
A well maintained Kubota engine is good for at least 5000 hours if not abused. A compression test will tell you a lot about it condition. V1702 compression should be 427-469 psi with no more than 50 psi difference between cylinders.
Drive chain life depends on how the machine has been used. Since you don't know when the chaincase oil was replaced last you should remove the front cover, check the oil and chains condition.
Lift the machine and block it up. Check each wheel for up-down and in-out play. Also look for oil seepage at the axle tube/flange area.

Check and grease the u-joints that connect the engine to the pumps. If they fail it will cause catastrophic damage.

Thanks Don, I checked the chains, with the wheels off the ground and I have about 1/2" rotational free movement, would that indicate the chains are ok for now, or do I still need to remove the front cover? Waiting for the manual to see how to grease the U joint. Thanks, Bill

 

[Tazza]

Thanks Don, I checked the chains, with the wheels off the ground and I have about 1/2" rotational free movement, would that indicate the chains are ok for now, or do I still need to remove the front cover? Waiting for the manual to see how to grease the U joint. Thanks, Bill

I actually fabricated a grill for a machine i had, i got some punched mesh, angle iron and flat bar stock. Made up a frame and wended the punched mesh to it, worked great.
The u-joints are a pain to access, lift the cab, lay on the pumps, use a grease gun with a long hose, double one if you can. Get a helper to rotate the engine by hand till the grease nipples line up.
Some are so negelected that they will not take grease, you need to pull the engine and replace them if they are that bad.
Good luck with your machine

 

[wbecker319]

I actually fabricated a grill for a machine i had, i got some punched mesh, angle iron and flat bar stock. Made up a frame and wended the punched mesh to it, worked great.
The u-joints are a pain to access, lift the cab, lay on the pumps, use a grease gun with a long hose, double one if you can. Get a helper to rotate the engine by hand till the grease nipples line up.
Some are so negelected that they will not take grease, you need to pull the engine and replace them if they are that bad.
Good luck with your machine

Is there just 1 grease fitting on the U joint, or 2? I'm going to take the front chain case cover off change the oil and check the chains. How loose is too loose? Do I need to get the chain oil from Bobcat, or what other oil can I use? I'm thinking theirs would be expensive, for 32 quarts.

 

[OldMachinist]

Is there just 1 grease fitting on the U joint, or 2? I'm going to take the front chain case cover off change the oil and check the chains. How loose is too loose? Do I need to get the chain oil from Bobcat, or what other oil can I use? I'm thinking theirs would be expensive, for 32 quarts.

3 grease fittings.

With the results you got with rotating the wheels it sounds like your chains are good. You can use engine oil or hydraulic oil in the chaincase.

 

[wbecker319]

3 grease fittings.



With the results you got with rotating the wheels it sounds like your chains are good. You can use engine oil or hydraulic oil in the chaincase.

Thanks to all for the help, I got the parts manual today, still waiting for operator and service. What engine oil would you recommend for the chain case? This is all new for me never been around one before, just old tractors and airplanes.

 

[antfarmer2]

Thanks to all for the help, I got the parts manual today, still waiting for operator and service. What engine oil would you recommend for the chain case? This is all new for me never been around one before, just old tractors and airplanes.

If your hydro oil looks ok put that in your case and put new in the hydro

 

[wbecker319]

If your hydro oil looks ok put that in your case and put new in the hydro

So now I have all the manuals and have changed fluid, still need to grease the U joint. I want to power wash the machine, just a little afraid of doing harm to electrical connectors hydraulic cylinder seals etc, thought I'd wrap them in plastic and zip Tye, any thoughts or cautions on a though power wash, this thing really needs a good cleaning?

 

[frogfarmer]

So now I have all the manuals and have changed fluid, still need to grease the U joint. I want to power wash the machine, just a little afraid of doing harm to electrical connectors hydraulic cylinder seals etc, thought I'd wrap them in plastic and zip Tye, any thoughts or cautions on a though power wash, this thing really needs a good cleaning?

I am not a fan of power washing at all. My machines get a garden hose only. If it takes more than that I will remove the crud with a putty knife or something similar. As you mention the electrical can be problematic from water intrusion but the cylinder seals should be able to take the pressure no problem. Bearing seals are another issue. You can introduce high pressure water into a bearing that will hold that water until it destroys the bearing and associated parts.

 

[wbecker319]

I am not a fan of power washing at all. My machines get a garden hose only. If it takes more than that I will remove the crud with a putty knife or something similar. As you mention the electrical can be problematic from water intrusion but the cylinder seals should be able to take the pressure no problem. Bearing seals are another issue. You can introduce high pressure water into a bearing that will hold that water until it destroys the bearing and associated parts.

I am ready to grease the U joint, I see the manual calls for U joint grease 6599719. I purchased a service kit from Bobcat that had filters and grease 6903122 included in it. Is the grease in the service kit ok to use on the U joints? Or should I get the grease call for in the manual? Thanks, Bill

 

[antfarmer2]

I am ready to grease the U joint, I see the manual calls for U joint grease 6599719. I purchased a service kit from Bobcat that had filters and grease 6903122 included in it. Is the grease in the service kit ok to use on the U joints? Or should I get the grease call for in the manual? Thanks, Bill

I just greased mine with the best hi temp grease that I could find it was red I have my engine out so I replaced my u joints on my 743 let me know how it is with the engine in looks bad not sure if my big axx will fit to do it

 

[Tazza]

I just greased mine with the best hi temp grease that I could find it was red I have my engine out so I replaced my u joints on my 743 let me know how it is with the engine in looks bad not sure if my big axx will fit to do it

I too would just use quality grease, no need for special stuff i don't believe. It should be running pretty straight, not in extreme situations like it would be on a vehicle causing it to move in all different angles.