I have a 93 743b.right side drive pulls fine in reverse,but in forward you have to rock the stick from forward to nutral several times to get it to engage.when it does its all in,if you ease off a little then it will quit pulling and you have to do again.have the same problem with reverse on left side.can push on a tree and spin both tires in both directions once it hits.bought used and have allways had this problem.had machine 3 years and put a half hour on it.time to fix or scrap.i have never worked on a bobcat b4.but im a decent gear head. all help taken into advisement.thanks
743 B drive motor failure?
- Thread starter trull007
- Start date
SSdoxie
Elite Member
Good power in one direction but not the other means the pump & motor hard parts are OK. Either motor seal(s) leaking or directional check valve/relief is hanging up. Because same problem is in both motors but opposite directions makes me think the same seal is worn & by-passing in both motors.
can you tell me off the top of your head
are the motors a pain to remove?im looking online for a service manual,i think that would be a smart way to go instead of flying blind.also I need to replace the glow plugs
I found them for about 20 bucks apeace. that sound about right.im gonna try to rebuild the drive motors myself. will post pic's of pass or fail.lol just really want to see if I
have the skills to do so. im a truckdriver so progress will be slow.thanks for the tips.great site and good people.
are the motors a pain to remove?im looking online for a service manual,i think that would be a smart way to go instead of flying blind.also I need to replace the glow plugs
I found them for about 20 bucks apeace. that sound about right.im gonna try to rebuild the drive motors myself. will post pic's of pass or fail.lol just really want to see if I
have the skills to do so. im a truckdriver so progress will be slow.thanks for the tips.great site and good people.
SSdoxie
Elite Member
Motors come off easy. Remove access plate between the wheels to see the motor. Remove the hoses, be sure to mark them to get back on the same fitting location, then unbolt the motor and slide it out. The output shaft is splined and slides into an internal splined sprocket shaft.
Before taking motor apart be sure to mark each and every section of the motor very distinctly so you reassemble all the sections in exact same position. It is very easy to accidentally invert one of the middle sections or get 90-180 degree out.
Before taking motor apart be sure to mark each and every section of the motor very distinctly so you reassemble all the sections in exact same position. It is very easy to accidentally invert one of the middle sections or get 90-180 degree out.
I pulled both drive motors today.they look really greasy and when I pulled them water ran out of both chain drive boxes.i have the numbers off the tags and houseings. wich number is the motor model number for ordering seal and bushing kits?numbers are 6657024 on tag.stamped into motor housing were 23 92 and also 17397 on one motor
6657024 on tag. 17384 on housing.
6657024 on tag. 17384 on housing.
SSdoxie
Elite Member
Number 6657024 is the Bobcat part number. 23 92 is build date code of the motor (23rd week of 1992). 17397 & 17384 are the serial number of each motor. I suspect these are Eaton motors but have no idea what model or series they are.
Water running out when motor was removed means you have substantial water in the chain case. It should be drained and cleaned out. The drain is at the rear center of the chain case, under the machine. Crawl under and right where the flat bottom of the chain case meets with the frame under the engine, where it starts to taper up towards the back there is an access plate to remove. In the access are 2 rubber plugs with metal expander pin in them. One plug is for the chain case (faces forward) and other is the fuel tank (faces to rear). Pull that plug and drain the chain case. Be prepared with large volume containers to catch the fluid. Normally there is 8 gallon hydraulic fluid, but with addition of water that chain case can easily hold over 25 gl. without pushing it out the top vent.
Since fuid/water came out of the chain case with motor off it means the motor carrier seals are shot, need to replace them as well. Seals can be replaced without taking the carrier off, drill small holes 180 degrees from each other in the seal and screw a sheet metal screw in part way to use the screws to pull the seals.
From what you have given me here is list of part items you will need:
2 motor seal kits
2 carrier seals
8 gallon hydraulic fluid (minimum to refill chain case)
2 motor case drain filters (any time you repair drive motors or have carrier seals blown, replace these filters).
Water running out when motor was removed means you have substantial water in the chain case. It should be drained and cleaned out. The drain is at the rear center of the chain case, under the machine. Crawl under and right where the flat bottom of the chain case meets with the frame under the engine, where it starts to taper up towards the back there is an access plate to remove. In the access are 2 rubber plugs with metal expander pin in them. One plug is for the chain case (faces forward) and other is the fuel tank (faces to rear). Pull that plug and drain the chain case. Be prepared with large volume containers to catch the fluid. Normally there is 8 gallon hydraulic fluid, but with addition of water that chain case can easily hold over 25 gl. without pushing it out the top vent.
Since fuid/water came out of the chain case with motor off it means the motor carrier seals are shot, need to replace them as well. Seals can be replaced without taking the carrier off, drill small holes 180 degrees from each other in the seal and screw a sheet metal screw in part way to use the screws to pull the seals.
From what you have given me here is list of part items you will need:
2 motor seal kits
2 carrier seals
8 gallon hydraulic fluid (minimum to refill chain case)
2 motor case drain filters (any time you repair drive motors or have carrier seals blown, replace these filters).
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hello ssdoxie, used search and found this thread ....so. i also have the drive motor issue brought to local farmer who has told me motor is toast so where do i find parts or a used replacement. or anyone else that might know please chime in please.
SSdoxie
Elite Member
Best reliable place to get motor or parts is from a Bobcat dealer. If that is not possible, there should be a tag on the motor identifying make model and specification numbers. With that number a hydraulics shop should be able to find something.
colson04
New member
Any updates on how your drive motor rebuild went? I'm curious how things went for you as I have a 743 that is going to need some serious TLC this summer and I'm trying to learn everything I can about this ol girl.