Bobcat 642 question

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drdent

Member
Joined
Nov 11, 2007
Messages
18
I have a Bobcat 642. I just rebuilt the engine and now the Hydrostatic drive pump has gone out. When the Bobcat is on a lift one side the tires spin reely and the other side does not. I am tired of working on it and was wondering what this would be worth if I was to sell it or trade it in. Thanks for any help you can give me. I will try to post some pics.
 
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drdent

Member
Joined
Nov 11, 2007
Messages
18
bobcatJan2006IM004692.jpg bobcat1 picture by Dakotama95


bobcatJan2006IM004696.jpg picture by Dakotama95


bobcatJan2006IM004694.jpg picture by Dakotama95
 

Tazza

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Dec 7, 2004
Messages
16,840
WOW
You have put a lot of time into that, honestly you should finish the job! If its worn swash plates you can fix that with sandpaper and a sheet of glass. Now, the drive problem, its only one sire rite? so when you push into a pile of dirt only one side spins?
If you simply traded it in the current condition i really don't know what you would get.... I would assume less than you have spent on paint and the engine.
 

skidsteer.ca

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Joined
Jan 20, 2006
Messages
3,853
WOW
You have put a lot of time into that, honestly you should finish the job! If its worn swash plates you can fix that with sandpaper and a sheet of glass. Now, the drive problem, its only one sire rite? so when you push into a pile of dirt only one side spins?
If you simply traded it in the current condition i really don't know what you would get.... I would assume less than you have spent on paint and the engine.
That one is a gas engine?
Anywhere near Mn, have a friend who is looking for a older loader.
Ken
 
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drdent

Member
Joined
Nov 11, 2007
Messages
18
WOW
You have put a lot of time into that, honestly you should finish the job! If its worn swash plates you can fix that with sandpaper and a sheet of glass. Now, the drive problem, its only one sire rite? so when you push into a pile of dirt only one side spins?
If you simply traded it in the current condition i really don't know what you would get.... I would assume less than you have spent on paint and the engine.
I have pretty much decided to go ahead and finish the job. The machine used to belong to my dad so I really don't want to just replace it. so does anyone have a scoop on used parts? I was mainly worried about breaking the chain to replace the hydrostat motor, but I was told that the motor has a spline shaft and will pull out of the gears without removing the chains. so as soon as I find a motor, I will finish the job Thanks Mike
 

Tazza

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Staff member
Joined
Dec 7, 2004
Messages
16,840
I have pretty much decided to go ahead and finish the job. The machine used to belong to my dad so I really don't want to just replace it. so does anyone have a scoop on used parts? I was mainly worried about breaking the chain to replace the hydrostat motor, but I was told that the motor has a spline shaft and will pull out of the gears without removing the chains. so as soon as I find a motor, I will finish the job Thanks Mike
Are you sure its the motor?
The hydrostatic pump is devided into 2 seperate sections, one for left one for right. One section could be bad and replacing the motor will not fix it.
Some motors are not joined inside the chain case, and even the ones that are i don't believe they are directally connected to the chain anyway, they go thorugh a gearbox. Try removing the 3 hoses and the 4 large bolts and see it the motor will slide out. I would then try swapping motors and see if the problem moves to the other side, if it does its the motor if not its the pump.
Both pumps and motors are still available for this machine. A fully re-built pump is 2,300 including a refundable $500 core charge and the motors would be around the 500 mark. If you have some mechanical ability you should be able to repair the pump for almost nothing if its just wear on the swash plates. If i remember i will post a link for these, i don't have it available to me at work.
I have done a fair bit or work on 743s that are essentially the same, they use the same pump and motors. You can contact me direct if you wish, my e-mail is in my user profile.
With propper care the machine will last you many years.
 

sterlclan

Well-known member
Joined
May 1, 2004
Messages
528
Are you sure its the motor?
The hydrostatic pump is devided into 2 seperate sections, one for left one for right. One section could be bad and replacing the motor will not fix it.
Some motors are not joined inside the chain case, and even the ones that are i don't believe they are directally connected to the chain anyway, they go thorugh a gearbox. Try removing the 3 hoses and the 4 large bolts and see it the motor will slide out. I would then try swapping motors and see if the problem moves to the other side, if it does its the motor if not its the pump.
Both pumps and motors are still available for this machine. A fully re-built pump is 2,300 including a refundable $500 core charge and the motors would be around the 500 mark. If you have some mechanical ability you should be able to repair the pump for almost nothing if its just wear on the swash plates. If i remember i will post a link for these, i don't have it available to me at work.
I have done a fair bit or work on 743s that are essentially the same, they use the same pump and motors. You can contact me direct if you wish, my e-mail is in my user profile.
With propper care the machine will last you many years.
you can switch the hoses on the pump from front to back and test it to see if it is the pump or the drive motor but....after switching them the steering levers will work backwards and be on opposite sides i would do this on jack stands or blocking if it is the pump its not that tough to repair it......most likely it is swash plates I fixed mine for about 50 bucks most of that was sandpaper good luck......Jeff
 

jplacz2000

Active member
Joined
Dec 27, 2011
Messages
29
you can switch the hoses on the pump from front to back and test it to see if it is the pump or the drive motor but....after switching them the steering levers will work backwards and be on opposite sides i would do this on jack stands or blocking if it is the pump its not that tough to repair it......most likely it is swash plates I fixed mine for about 50 bucks most of that was sandpaper good luck......Jeff
how did you do splash plates ?? i have to do them on mine when you turn it really struggles and wines
 

SkidRoe

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Joined
Dec 10, 2009
Messages
1,885
how did you do splash plates ?? i have to do them on mine when you turn it really struggles and wines
You may want to think about starting a new post. This one is old and many of the respondants have not been online here for years. HTH
 

sterlclan

Well-known member
Joined
May 1, 2004
Messages
528
You may want to think about starting a new post. This one is old and many of the respondants have not been online here for years. HTH
funny i just stopped in to cruise around and pow something i can help with... i split the main pump keeping the halves separate, removed the bronze wear plates and starting with 200 grit wet dry paper and some 10 40 oil sanded till smooth using the table saw top to support the paper,and spinning the wear plates all different directions (like a dual action sander) after 220 went to 400,and finished with 600 re assembled keeping all the parts oriented the same as diss assy. good luck
 

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