Three 743 Questions

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pondfishr

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Oct 11, 2005
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I have three questions about my Bobcat 743 1. I can't find the location to check the crankcase fluid. I think it is under the cab but I can's see any logical place it would be. Any ideas would be appreciated. 2. Looking at the front of the machine under the cab at my hydraulic pump the inlet hose that runs to the port block mounted to the right side of the machine is leaking slightly. The hose is held in place with radiator style hose clamps. I first thought this was something after market but I looked in my manual and it looks like it is a factory connection. Can I replace the hose easily or is it a big deal? 3. Also what type of Hydraulic fluid can I use in my machine. I had been using Bobcat brand but that stuff is pretty expensive. I went to the Co-Op and bought their brand of Hydro fluid in a yellow 5 gallon bucket but I want to be sure I can use it. My machine is older and I try to take care of it until. Scheduled maintenance is pretty important in making things last. Thanks in advance for the help this is the best forum on the net/
 

Tazza

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Chain case fluid is checked by removing the big nut at the front of the chain case where the bobtach is. Get on the ground and look at the front behind the bobtach, its about 1 1/8”. The level is correct if on level ground, oil just trickles out or you can feel it with your finger. If its white i needs changing as you have water contamination.
That hose is OEM, leave it alone if you can. Changing it is a bit difficult as its quite stiff, the only way i could un-do it was to remove the bolts on the pump and pull it off that way when i needed to remove the pump. Depending on where its leaking you can put 2 more clamps on it. It may also help to ask the dealer what they think. The new hose may be flexible enough to install it without removing anything i know know my old one was too stiff.
Oil, ANY standard car engine oil is suitable. NEVER use hydraulic oil, its too thin. You want 10W30 to say 20W50.
 

pondfishr

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Joined
Oct 11, 2005
Messages
215
Chain case fluid is checked by removing the big nut at the front of the chain case where the bobtach is. Get on the ground and look at the front behind the bobtach, its about 1 1/8”. The level is correct if on level ground, oil just trickles out or you can feel it with your finger. If its white i needs changing as you have water contamination.
That hose is OEM, leave it alone if you can. Changing it is a bit difficult as its quite stiff, the only way i could un-do it was to remove the bolts on the pump and pull it off that way when i needed to remove the pump. Depending on where its leaking you can put 2 more clamps on it. It may also help to ask the dealer what they think. The new hose may be flexible enough to install it without removing anything i know know my old one was too stiff.
Oil, ANY standard car engine oil is suitable. NEVER use hydraulic oil, its too thin. You want 10W30 to say 20W50.
Tazza are you talking about the hydraulic system or the chain case concerning the replacement fluid comment? I spoke to the local Bobcat dealer "Bobcat of Nashville" and they told me not to use the oil it will foam. That doesn't make sense my Bobcat service manual states to use Bobcat hydraulic fluid part #6563328 first and if it is not available use 10W30 or 10W40 SAE Motor Oil. The dealer also said I could change hydraulic fluid types but I must drain the hydraulic system first and re-fill. If I did not drain the system I need to continue to use the Bobcat brand hydraulic fluid.
 

Tazza

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Tazza are you talking about the hydraulic system or the chain case concerning the replacement fluid comment? I spoke to the local Bobcat dealer "Bobcat of Nashville" and they told me not to use the oil it will foam. That doesn't make sense my Bobcat service manual states to use Bobcat hydraulic fluid part #6563328 first and if it is not available use 10W30 or 10W40 SAE Motor Oil. The dealer also said I could change hydraulic fluid types but I must drain the hydraulic system first and re-fill. If I did not drain the system I need to continue to use the Bobcat brand hydraulic fluid.
You can run engine oil in the hydraulics and chain case.
I used 15W40 in my entire machine until i couldn't get a good price on it any more and now use 20W50 in hydraulics and chain case. The engine still uses 15W40 diesel grade oil.
The machine is old so warranty isn't an issue, use engine oil as its far cheaper than from bobcat.
As for the oil foaming, it will not foam unless you have air in the system or the oil is too thin, like hydraulic oil is.
You simply can't drain ALL the hydraulic oil from the entire system either, you have oil in the cylinders, oil cooler, hoses/tube lines motors and pumps you simply can't get out short of removing and draining each piece.
 
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