What are the 743 Side Covers?

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pondfishr

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On the 743 there are square side covers on both sides of the machine between the tires. They have some kind of sealer or caulking around the edges. I considered putting a jack in that area but don't want to damage the cover or what's inside. Can someone explain what they are for?
 

bobo

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The covers that you are talking about are the covers to protect your drive motors.I would not suggest jacking at those point as that will surely damage your machine.
 

Tazza

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The covers that you are talking about are the covers to protect your drive motors.I would not suggest jacking at those point as that will surely damage your machine.
I would not recommend it either. I always lift under the chain case or the rear under the engine. As bobo said, its just a cover to protect? or maybe pretty the machine up a bit so you can't see the drive motors and hoses.
 
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pondfishr

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I would not recommend it either. I always lift under the chain case or the rear under the engine. As bobo said, its just a cover to protect? or maybe pretty the machine up a bit so you can't see the drive motors and hoses.
Thanks. Can you see anything to reference the motors when you have the cab lifted?
 

Tazza

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Thanks. Can you see anything to reference the motors when you have the cab lifted?
Not too sure what you mean there, but if you mean can you see where the drive motors are, yes you can with the cab up. Not that you have any access to them, but you can see them from the top.
 
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pondfishr

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Not too sure what you mean there, but if you mean can you see where the drive motors are, yes you can with the cab up. Not that you have any access to them, but you can see them from the top.
A stupid question but how do the drive motors connect to the chain sprockets? Does the connection take place inside inside the cover and the hydraulic hose comes through the top. I assume the hydraulic flow rate drives the motors to turn the wheels, If the covers were damaged would the machine lose chain case oil out the cover. Sorry for so many questions but you guys are great in helping me understand the machinery. Also is this a common design in most bobcats or is this something that went away after they quit making 743's.
 

Tazza

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A stupid question but how do the drive motors connect to the chain sprockets? Does the connection take place inside inside the cover and the hydraulic hose comes through the top. I assume the hydraulic flow rate drives the motors to turn the wheels, If the covers were damaged would the machine lose chain case oil out the cover. Sorry for so many questions but you guys are great in helping me understand the machinery. Also is this a common design in most bobcats or is this something that went away after they quit making 743's.
Not a problem what so ever!
The drive motors don't connect to the sprockets directly, they go through a reduction drive first. They fit into a matching spine to engage, you more or less have a direct connection (speed wise) to your park brake disc's, so your brake actually holds the power the drive motor puts out directly not after it has been reduced which means they can use a smaller brake setup.
The drive motors are VERY simple to remove. Remove the 3 hoses, then remove the 4 bolts on the motor housing to the reduction box. Simply pull the motor out and it will disengage the drive spline. The cover does absolutely nothing but to protect the motor and make it look *pretty*. Damaged covers will not do a thing to loose oil, they are just covers that bolt to the chassis with 4 bolts. The sealant looking stuff you see on the outside is just rubber to fill the space between the chassis and the cover, there is no seal underneath. If you are leaking chain case fluid, it could be the O ring between the motor and reduction box but if its on the right side (while sitting in the machine) it may be your control block seals. This design was common from 743/743B and earlier, my 731 had the exact same setup for the motor mounting.
I will try and scan in details of this at work tomorrow, it is very simple. If you want to e-mail me direct, check my e-mail in the user profiles. Unfortunately i know FAR too much about 743 machines.....
If any of that isn't clear just yell!
 

Tazza

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Not a problem what so ever!
The drive motors don't connect to the sprockets directly, they go through a reduction drive first. They fit into a matching spine to engage, you more or less have a direct connection (speed wise) to your park brake disc's, so your brake actually holds the power the drive motor puts out directly not after it has been reduced which means they can use a smaller brake setup.
The drive motors are VERY simple to remove. Remove the 3 hoses, then remove the 4 bolts on the motor housing to the reduction box. Simply pull the motor out and it will disengage the drive spline. The cover does absolutely nothing but to protect the motor and make it look *pretty*. Damaged covers will not do a thing to loose oil, they are just covers that bolt to the chassis with 4 bolts. The sealant looking stuff you see on the outside is just rubber to fill the space between the chassis and the cover, there is no seal underneath. If you are leaking chain case fluid, it could be the O ring between the motor and reduction box but if its on the right side (while sitting in the machine) it may be your control block seals. This design was common from 743/743B and earlier, my 731 had the exact same setup for the motor mounting.
I will try and scan in details of this at work tomorrow, it is very simple. If you want to e-mail me direct, check my e-mail in the user profiles. Unfortunately i know FAR too much about 743 machines.....
If any of that isn't clear just yell!
Sorry, the new style machines i believe are essentially the same with how the motor attaches to the reduction box. Just larger motors i believe, and the covers are different.
 

Tazza

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Sorry, the new style machines i believe are essentially the same with how the motor attaches to the reduction box. Just larger motors i believe, and the covers are different.
Ok, i have the pages scanned, i just need to reduce the file size down a bit then i will post them up. I can send you the larger files if you wish, just send me an e-mail and i will send direct. If not, i will try and make a little space and host them myself so you can get the detail required.
 

Tazza

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Ok, i have the pages scanned, i just need to reduce the file size down a bit then i will post them up. I can send you the larger files if you wish, just send me an e-mail and i will send direct. If not, i will try and make a little space and host them myself so you can get the detail required.
Ok, i'm still at work but have uploaded the files:
http://users.tpg.com.au/tazza_/drive/Drive Train.jpg
http://users.tpg.com.au/tazza_/drive/Gear Case.jpg
http://users.tpg.com.au/tazza_/drive/Hydro Motor.jpg
See how you go with that.
 

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