bobcat 743b drive motor

[bobcat743b]

well i think my drive motor on the right side needs rebuilt. never did this but i tihink i am going to try it. looks as though theres 3 lines to remove then 4 bolts to remove then it should pull straight off. how much oil will i lose when i take the lines off. i found a u tube video of a fellow overhauling one on a 743b. the number on the drive motor is 18073. my 743b is a 92-93 model. where is a good place to get the o ring kit. they seem kinda pricey so i want to get the correct kit. any comments, suggestions' are welcome. could use a parts diaghram for it as ive tried to get into the bocat site but not having and luck with that. thanks for reading.

 

[flyerdan]

There should be at least a couple service manuals for the743 series machines in the manual thread.
Bobcatpartsonline will have a breakdown of all the parts, and part numbers so you can search online for the best prices, often found on ebay.
If you enter your serial number in the s/n field it will bring up all parts specific to your machine.

 

[Tazza]

There should be at least a couple service manuals for the743 series machines in the manual thread.
Bobcatpartsonline will have a breakdown of all the parts, and part numbers so you can search online for the best prices, often found on ebay.
If you enter your serial number in the s/n field it will bring up all parts specific to your machine.

If you use rags and tape to plug the hoses, you won't loose a heap of oil, the case drain line is the one i'd feel woudl leak the most (the little one). Rags, even plastic bags wrapped tightly and taped should minimize it.
The hardest part is timing the motor, you have holes in a valve plate you need to match up to ensure it turns the correct way.

 

[bobcat743b]

If you use rags and tape to plug the hoses, you won't loose a heap of oil, the case drain line is the one i'd feel woudl leak the most (the little one). Rags, even plastic bags wrapped tightly and taped should minimize it.
The hardest part is timing the motor, you have holes in a valve plate you need to match up to ensure it turns the correct way.

i noticed there s a couple allen screws you remove and there is a spring in there. can someone tell me the purpose of that spring. thanks

 

[flyerdan]

i noticed there s a couple allen screws you remove and there is a spring in there. can someone tell me the purpose of that spring. thanks

A quick look in the book indicates that these are probably the springs for the shuttle valves.
Somewhere in the manual thread is a book for these motors- Motor Component Repair Manual that exclusively covers all aspects of overhaul.
There are also specific books for the control valves and hydraulic cylinders. I would strongly recommend having a good trawl through all the links and saving locally everything you're interested it, just to make it easy to find later if nothing else.

 

[bobcat743b]

A quick look in the book indicates that these are probably the springs for the shuttle valves.
Somewhere in the manual thread is a book for these motors- Motor Component Repair Manual that exclusively covers all aspects of overhaul.
There are also specific books for the control valves and hydraulic cylinders. I would strongly recommend having a good trawl through all the links and saving locally everything you're interested it, just to make it easy to find later if nothing else.

i am trying to get an understanding of how it all works before i tear it apart. took the right motor off. went on the bobcat site to check for a seal kit and parts diagram. number on my motor 25-92 so i suspect that's when it was made. that corresponds with the serial number which is 509318212. another number on the plate that is 6657024. not sure what that number is as when i go to the parts listing there is no such number i can find. also a number stamped 18073. don't have a clue what its for. just trying to get the correct seal kit ordered. they show a seal kit 6686403 but not positive its the right one also it wont allow me the print the parts diagram. just parts numbers. . thanks so far for the help. just need a little more. put an oil catcher down and didnt get a lot of oil.

 

[flyerdan]

i am trying to get an understanding of how it all works before i tear it apart. took the right motor off. went on the bobcat site to check for a seal kit and parts diagram. number on my motor 25-92 so i suspect that's when it was made. that corresponds with the serial number which is 509318212. another number on the plate that is 6657024. not sure what that number is as when i go to the parts listing there is no such number i can find. also a number stamped 18073. don't have a clue what its for. just trying to get the correct seal kit ordered. they show a seal kit 6686403 but not positive its the right one also it wont allow me the print the parts diagram. just parts numbers. . thanks so far for the help. just need a little more. put an oil catcher down and didnt get a lot of oil.

If you google 6657024 it comes up as this LPS replacement to replace a replacement of the OEM number.
The middle motor in the bobcat parts catalog that is listed as NLA refers to the LPS replacement number so the 6686403 seal kit should be for the motor you have.
The third motor in the bobcat parts catalog is the replacement 6681605, which lists the same seal kit number.

 

[bobcat743b]

If you google 6657024 it comes up as this LPS replacement to replace a replacement of the OEM number.
The middle motor in the bobcat parts catalog that is listed as NLA refers to the LPS replacement number so the 6686403 seal kit should be for the motor you have.
The third motor in the bobcat parts catalog is the replacement 6681605, which lists the same seal kit number.

watched the video on a guy installing a seal kit in the motor drive . he has the same motor drive i do. looks as though he is installing a 6659601 seal kit. i called bobcat and that was the number also. i saw three motors listed on the bobcat site. the one 137-100-002 looks thats what i have. . there pricey for sure. pulled the spring out of the motor. there are 4 very large allen screws i need to remove. i dont have that size. would anyone know for sure what size i need to buy. i think its close to 1/2 inch. i want to get it all a part to make sure its okay before i buy the seal kit. also i cant print out the parts diagram from the bobcat site. so would anyone have that they could email me so could print it out.

 

[bobcat743b]

watched the video on a guy installing a seal kit in the motor drive . he has the same motor drive i do. looks as though he is installing a 6659601 seal kit. i called bobcat and that was the number also. i saw three motors listed on the bobcat site. the one 137-100-002 looks thats what i have. . there pricey for sure. pulled the spring out of the motor. there are 4 very large allen screws i need to remove. i dont have that size. would anyone know for sure what size i need to buy. i think its close to 1/2 inch. i want to get it all a part to make sure its okay before i buy the seal kit. also i cant print out the parts diagram from the bobcat site. so would anyone have that they could email me so could print it out.

went to bobcat day. got a print out of my drive motor parts numbers and diagram of the motor. got the large allen screws loose. getting ready to take al apart to inspect and clean. any precaution i should make before i take it apart. i will mark the outside so i can get the casing back where it was. did get some dirty oil from the little spring ass i took out. been busy with medical problems so sort of slow.

 

[Tazza]

went to bobcat day. got a print out of my drive motor parts numbers and diagram of the motor. got the large allen screws loose. getting ready to take al apart to inspect and clean. any precaution i should make before i take it apart. i will mark the outside so i can get the casing back where it was. did get some dirty oil from the little spring ass i took out. been busy with medical problems so sort of slow.

The main part you want to be careful is the geroler section. This is the part with the rollers and star looking part. Ideally you do not want to put the rollers in different holes. They will have worn, so you are meant to keep them in the same position.
It's not as hard of a job as it may first seem, once you have done it once, you'll wonder why you put that much thought into it.

 

[bobcat743b]

The main part you want to be careful is the geroler section. This is the part with the rollers and star looking part. Ideally you do not want to put the rollers in different holes. They will have worn, so you are meant to keep them in the same position.
It's not as hard of a job as it may first seem, once you have done it once, you'll wonder why you put that much thought into it.

i took it apart today. havent removed the geroler yet. i wanted to mark each roller so i could put them back in the same hole. did find one of the plastic o rings broken and one rubber o ring little rough but everything else looks okay. little dirt. ordered a kit today. thanks for the help

 

[bobcat743b]

i took it apart today. havent removed the geroler yet. i wanted to mark each roller so i could put them back in the same hole. did find one of the plastic o rings broken and one rubber o ring little rough but everything else looks okay. little dirt. ordered a kit today. thanks for the help

recieved the kit. what do you all put on the new o rings if anything when you install them and what lub do you put on the grollers and such when you put it back together. thanks

 

[foton]

recieved the kit. what do you all put on the new o rings if anything when you install them and what lub do you put on the grollers and such when you put it back together. thanks

I would use the same oil that you are using in that system

 

[bobcat743b]

I would use the same oil that you are using in that system

so i got the kit for my 743b left motor. got it all installed. put the motor back on tighted on the bolts. got the small drain line hooked up but i have problem with the two big lines. should have marked them better i know. one line has like a brass piece and one a silver piece on it. as your looking at the motor can someone tell me where they go. one line goes to the left side of the hyd pump as your sitting n the seat and it has a yellow flange. the other hose goes to the right side of the hyd pump as your sitting in the seat. manual isnt clear enough. cross my fingers. show time when i get this problem solved. thanks