642 B I need help guys!

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Barfly69

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Dec 19, 2007
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I finally talked my wife into allowing me to buy a Bobcat to supplement our income, snow removal, landscapeing etc. Anyway I took my time looking and found a good deal, well a deal I thought was good I found this 1991 642 B gas engine 4 litre mitubitshi with 2400 hours on it it also came with a 18 foot Trailtech trailer hydraulic lift as well with 4 buckets 1 is a 8 foot snow bucket the other 3 are 1/3 yd standard and finally a snowblade. The motor runs perfectly the bucket operations also work perfectly as I only used it so far to clean up driveways around the neigbourhood it seemed to run great. The older gentleman I bought it from used it primarilly to clean snow in his condiminium complex over the last 12 years for $4000 a month. Ok to the problem, yesterday I took it out of the garage to clean the snow in my backyard and it started to make a noise like a ice crushing noise from underneath along with some vibration when I attempted to go forward or reverse more so in the forward motion. I had taken it to the carwash a couple days earlier and am hoping it is maybe a ice build up somewhere underneath? Everything works it pivots and goes forward and reverse but the noise and vibration has me very concerned I store it in a insulated gargage although unheated. If it is something major I'm dead the wife will kill me :( Does anyone have any suggestions on what it possibly could be and what to look for? I really appreciate any advise anyone could give me, I have read numerous posts in here and you guys seem to be very friendly and intellegent in this area, I have looked in other forums and this one seems to be nooby friendly...haha. I am at your mercy thx in advance. :) Cal
 

skidsteer.ca

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Jan 20, 2006
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Cal
Is the garage above freezing inside so any ice would melt?
I'm kinda thinking it could be a problem with a axel/wheel bearing or drive chain.
There is one wheel motor on each side. It is hooked to the front and rear wheel on its respective side, motor between the wheels, one chain goes forward to the front wheel, the other back to the rear wheel, both hooked to the common motor.
A complete separate set of motor, chains on the other side.
I'd put it on blocks so the wheels can turn without the machine moving. Slowly rotate them forward and back and see if both wheels on the same side work together, if one of the wheels does not move with the other on the same side, say left then you have chain case problems
Bad wheel bearing can make loud crunching sounds and cause the bad wheel to jerk or stop.
Take heart, these are generally low maintenance machines.
Ken
 

OldMachinist

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May 24, 2006
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If you think it might be ice park it in the garage and get some heat in there to thaw it out. Rent or borrow a Salamander style heater and see how it sounds after it thaws out.
 
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Barfly69

Member
Joined
Dec 19, 2007
Messages
10
If you think it might be ice park it in the garage and get some heat in there to thaw it out. Rent or borrow a Salamander style heater and see how it sounds after it thaws out.
Wow you guys are great it took all of a half hour to start getting helpfull replies my hats off to you and this great forum. I will block it up and try that out Ken. :) If it is a chain problem do you know if it is an expensive fix? I'd have to take it to a dealer for repair I didn't get a manual with the machine and to be honest I'm not a very good mechanic I can do basic things oil changes plugs etc but to try something like that I would be getting into something I may be sorry for. Thx Ken :) And as far as thawing it out I am doing that right now I have the heaters going as we speak and I can only hope and pray that is the problem...haha. Thx Oldmachinist. :)
 

sterlclan

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May 1, 2004
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Wow you guys are great it took all of a half hour to start getting helpfull replies my hats off to you and this great forum. I will block it up and try that out Ken. :) If it is a chain problem do you know if it is an expensive fix? I'd have to take it to a dealer for repair I didn't get a manual with the machine and to be honest I'm not a very good mechanic I can do basic things oil changes plugs etc but to try something like that I would be getting into something I may be sorry for. Thx Ken :) And as far as thawing it out I am doing that right now I have the heaters going as we speak and I can only hope and pray that is the problem...haha. Thx Oldmachinist. :)
Not to insult you but did you check the parking brake? sometimes its the simple stuff that stumps us.those machines are plenty rugged good luck.....Jeff
 

Tazza

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Dec 7, 2004
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Not to insult you but did you check the parking brake? sometimes its the simple stuff that stumps us.those machines are plenty rugged good luck.....Jeff
You make a very good point! That will make the machine squeel and buck around.
Blocking it and running it is a good idea, that way you can tell if it is a chain problem and of the problem is on what side. Both sides are seperate as ken told you. Both the front and rear wheels on each side are linked together with 2 chains to a central sprocket driven by the hydraulic motor/gear box.
If its not the park brake i'd check the oil, if its white you have water contamination and the crunching you can hear and feel could be water in the chaincase that has frozen. If its contaminated you need to change the oil.
These machines are pretty well bullet proof, you need to do something major to kill them.
Let us know how you go!
 
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Barfly69

Member
Joined
Dec 19, 2007
Messages
10
You make a very good point! That will make the machine squeel and buck around.
Blocking it and running it is a good idea, that way you can tell if it is a chain problem and of the problem is on what side. Both sides are seperate as ken told you. Both the front and rear wheels on each side are linked together with 2 chains to a central sprocket driven by the hydraulic motor/gear box.
If its not the park brake i'd check the oil, if its white you have water contamination and the crunching you can hear and feel could be water in the chaincase that has frozen. If its contaminated you need to change the oil.
These machines are pretty well bullet proof, you need to do something major to kill them.
Let us know how you go!
Hi guys, no its not the oil I changed the oil the first day I got it I checked it after reading your reply and it is topped up and nice and clear. I got busy yesterday and wasn't able to block it up yet but this morning I went out to garage and was going to do just that when I decided to fire her up and try it again, well I did and it seemed to work fine? Not sure if it was because of the heaters yesterday or like you suggested the parking break? Btw where is the parking break? I do not have a manual and the only thing I can see that may resemble one is a black knobbed lever on the lefthand side of the seat, left as in when your seated left. It almost resembles the chock lever on the right I didn't touch it and won't until I know what it is. Anyway I wanted to update you guys you have been great and I have put this site on top in my saved favorites sites hopefully not to use it for this purpose again at least not right away...haha but to read and learn because you guys have a wealth of knowledge and it is fantastic that you share it with dummies like myself, I reallly really appreciate it guys thx alot and Merry Christmas! :)
 

Tazza

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Hi guys, no its not the oil I changed the oil the first day I got it I checked it after reading your reply and it is topped up and nice and clear. I got busy yesterday and wasn't able to block it up yet but this morning I went out to garage and was going to do just that when I decided to fire her up and try it again, well I did and it seemed to work fine? Not sure if it was because of the heaters yesterday or like you suggested the parking break? Btw where is the parking break? I do not have a manual and the only thing I can see that may resemble one is a black knobbed lever on the lefthand side of the seat, left as in when your seated left. It almost resembles the chock lever on the right I didn't touch it and won't until I know what it is. Anyway I wanted to update you guys you have been great and I have put this site on top in my saved favorites sites hopefully not to use it for this purpose again at least not right away...haha but to read and learn because you guys have a wealth of knowledge and it is fantastic that you share it with dummies like myself, I reallly really appreciate it guys thx alot and Merry Christmas! :)
The park brake is on top of the chain case between your legs. Look for a metal paddle looking thingo. It should tip back towards you to dis-engage and forward to engage.
Merry x-mas to you too. Questions are always welcome.
 

OldMachinist

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May 24, 2006
Messages
2,748
The park brake is on top of the chain case between your legs. Look for a metal paddle looking thingo. It should tip back towards you to dis-engage and forward to engage.
Merry x-mas to you too. Questions are always welcome.
The chain case oil that Tazza talked about is in a reservoir at the very bottom of the machine. It is normally accessed by a threaded plug right below where you step into the cab. There is no drain plug you must pump or suck the old oil out through the threaded hole to change it. Is this the oil you changed when you got the machine?
 
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Barfly69

Member
Joined
Dec 19, 2007
Messages
10
The chain case oil that Tazza talked about is in a reservoir at the very bottom of the machine. It is normally accessed by a threaded plug right below where you step into the cab. There is no drain plug you must pump or suck the old oil out through the threaded hole to change it. Is this the oil you changed when you got the machine?
No I didn't check that oil I changed the motor oil damn am I dumb...haha. I will definately have a peek at it these are all good things to know thank you. Now that I know where the parking break is I am pretty sure that was the problem I almost always step there getting into the machine, thx again fellas and have a great Xmas. :)
 

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