632 weak, drive motors or hydrostat?

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PA.Johansson

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Hello, My Bobcat 632 seems weak somehow, when i'm pushing dirt it really can't push it. Last year when i bought the machine the tandem/hydrostat was broken, we changed the "coils" or what the english word for it is. So it's completely new on the inside. So my question now is, could we somehow put something wrong to cause these problems? I've also changed the bearings in the drive motors. There was a little bit rust inside the drive motors since the machine has been outside for about 5 years without proper cover for the motors. So I think the motors are the big problem here, but i just wanted to check with you guys if this problem could be caused by the hydrostat. Thanks guys! /A
 

jerry

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That model has the bronze filter in the square block atop the forward end of the hydro pumps. Three large hoses coming out on the left , filter is in the block when you take off the center hose. Did you change that also?
 
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PA.Johansson

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That model has the bronze filter in the square block atop the forward end of the hydro pumps. Three large hoses coming out on the left , filter is in the block when you take off the center hose. Did you change that also?
Hi Jerry, No I did not change it, i cleaned it with ultrasonic washing. So it should be clean now(at least all the dirt disappeared) and i tried to run it without the filter last year to see if something was wrong with the filter and it didn't change the weakness of the machine. /A
 

antfarmer2

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Hi Jerry, No I did not change it, i cleaned it with ultrasonic washing. So it should be clean now(at least all the dirt disappeared) and i tried to run it without the filter last year to see if something was wrong with the filter and it didn't change the weakness of the machine. /A
Put a pressure gauge on it
 
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PA.Johansson

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The drive motors have to be done right they are timed
Yes, we put a pressure gauge on it after we put it together and it seemed to be right as the books said.. We did only change the bearings to the axis on the drive motors and the timing was correct when we put them back. If the drive motors are worn out, what are the main symtoms for it? one of the drive motors sometimes makes a hard sound when i try to push something heavy, and for me this sounds like they can't keep the pressure? /A
 

antfarmer2

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Yes, we put a pressure gauge on it after we put it together and it seemed to be right as the books said.. We did only change the bearings to the axis on the drive motors and the timing was correct when we put them back. If the drive motors are worn out, what are the main symtoms for it? one of the drive motors sometimes makes a hard sound when i try to push something heavy, and for me this sounds like they can't keep the pressure? /A
Sorry do not know what it sounds like mine have not gone bad yet but I did buy the seal kit for them I think it was about $60 bucks from bobcat from what I have read the seals can go bad and get weak as long as it is not scored up you should be good also if you take them apart you have to seal the bolt threads or it will leak on mine it turned out to be the seal in the gear reduction box that was leaking and filled the chain case with hydro fluid
 

antfarmer2

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Sorry do not know what it sounds like mine have not gone bad yet but I did buy the seal kit for them I think it was about $60 bucks from bobcat from what I have read the seals can go bad and get weak as long as it is not scored up you should be good also if you take them apart you have to seal the bolt threads or it will leak on mine it turned out to be the seal in the gear reduction box that was leaking and filled the chain case with hydro fluid
If you are loosing hdro fluid check your chain case by pulling the big threaded plug on the front of the chain case the seals for that are $16 bucks apiece and I made a seal tool for under $5 bucks with a threaded pvp coupler and the threaded square plug from the hardware store it worked great!!!!!
 

Tazza

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If you are loosing hdro fluid check your chain case by pulling the big threaded plug on the front of the chain case the seals for that are $16 bucks apiece and I made a seal tool for under $5 bucks with a threaded pvp coupler and the threaded square plug from the hardware store it worked great!!!!!
If the motors are worn, you will not have as much pushing power. You mention rust was in there, if it rusted the geroler setion, oil will be by-passing so not as much power will be generated. It doesn't take much for that.
The pump parts, i assume you are talking rotating groups and the wear plates? these are what generates the pressure. And marks on the surfaces reduces it's effencicy.
Does the machine big down when pushing? it could be bad seals, $5 in O rings can generally do both motors if the plastic backup washers are not damaged. I had a motor that hd no power, replaced the O rings, it was perfect after that.
 
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PA.Johansson

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If the motors are worn, you will not have as much pushing power. You mention rust was in there, if it rusted the geroler setion, oil will be by-passing so not as much power will be generated. It doesn't take much for that.
The pump parts, i assume you are talking rotating groups and the wear plates? these are what generates the pressure. And marks on the surfaces reduces it's effencicy.
Does the machine big down when pushing? it could be bad seals, $5 in O rings can generally do both motors if the plastic backup washers are not damaged. I had a motor that hd no power, replaced the O rings, it was perfect after that.
I think the motors are worn out.. A few weeks ago i found a oil leak from the hydraulic oil tank hose to the hydrostat. It was not mounted right and was loose in the hydrostat so the spring inside could not get the right pressure. I fixed this and the machine somehow felt stronger, but still the turning is terrible. When standing still, I cant turn the machine at all. The copper filter was replaced with a same type of filter but is no longer mounted where to copper filter was. So, now i'm really thinking of buying new motors, i'm tired of working with this crap machine! Somehow the whole point with at bobcat is gone in my 632 when its impossible to turn standing still or push dirt. At first I was thinking that the hydraulic oil was getting too hot, but it reaches 50-60 degrees celcius, and this should not be to hot. I'm currently using a universal hydraulic oil 10w-30 that was recomended to this machine, should i try a different oil? but i don't think it could fix the problem. With all the rust inside the motors i think its impossible to fix them without replacing something. So, my question now is, I live in Sweden and only genuine bobcat parts are available here. the price for two new motors are more than what i paid for the whole machine, and somehow feels a bit risky to pay that much. Is there any other motors that can be mounted there somehow? loaderpartsrecources is an opinion, but when ordering to Sweden i'll need to pay import taxes..... Thank you guys! /A
 
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PA.Johansson

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I think the motors are worn out.. A few weeks ago i found a oil leak from the hydraulic oil tank hose to the hydrostat. It was not mounted right and was loose in the hydrostat so the spring inside could not get the right pressure. I fixed this and the machine somehow felt stronger, but still the turning is terrible. When standing still, I cant turn the machine at all. The copper filter was replaced with a same type of filter but is no longer mounted where to copper filter was. So, now i'm really thinking of buying new motors, i'm tired of working with this crap machine! Somehow the whole point with at bobcat is gone in my 632 when its impossible to turn standing still or push dirt. At first I was thinking that the hydraulic oil was getting too hot, but it reaches 50-60 degrees celcius, and this should not be to hot. I'm currently using a universal hydraulic oil 10w-30 that was recomended to this machine, should i try a different oil? but i don't think it could fix the problem. With all the rust inside the motors i think its impossible to fix them without replacing something. So, my question now is, I live in Sweden and only genuine bobcat parts are available here. the price for two new motors are more than what i paid for the whole machine, and somehow feels a bit risky to pay that much. Is there any other motors that can be mounted there somehow? loaderpartsrecources is an opinion, but when ordering to Sweden i'll need to pay import taxes..... Thank you guys! /A
Sorry, i mean the bronze filter...
 

jerry

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I think the motors are worn out.. A few weeks ago i found a oil leak from the hydraulic oil tank hose to the hydrostat. It was not mounted right and was loose in the hydrostat so the spring inside could not get the right pressure. I fixed this and the machine somehow felt stronger, but still the turning is terrible. When standing still, I cant turn the machine at all. The copper filter was replaced with a same type of filter but is no longer mounted where to copper filter was. So, now i'm really thinking of buying new motors, i'm tired of working with this crap machine! Somehow the whole point with at bobcat is gone in my 632 when its impossible to turn standing still or push dirt. At first I was thinking that the hydraulic oil was getting too hot, but it reaches 50-60 degrees celcius, and this should not be to hot. I'm currently using a universal hydraulic oil 10w-30 that was recomended to this machine, should i try a different oil? but i don't think it could fix the problem. With all the rust inside the motors i think its impossible to fix them without replacing something. So, my question now is, I live in Sweden and only genuine bobcat parts are available here. the price for two new motors are more than what i paid for the whole machine, and somehow feels a bit risky to pay that much. Is there any other motors that can be mounted there somehow? loaderpartsrecources is an opinion, but when ordering to Sweden i'll need to pay import taxes..... Thank you guys! /A
Try engaging the auxillary hydraulics at idle speed or a little faster. With nothing attached to the couplers it should kill the engine or at least make it really labor. It will give you a idea whether or not your pump is working.
 
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PA.Johansson

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Try engaging the auxillary hydraulics at idle speed or a little faster. With nothing attached to the couplers it should kill the engine or at least make it really labor. It will give you a idea whether or not your pump is working.
Hi, That is allready something i've checked. Te break is not stuck or anything. How hot should the oil get? what is the maximum? The problem follows if I change the sides on the motors. I tried that, and it almost killed the engine and started to "work harder". So everything seems fine with it? or? :)
 
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PA.Johansson

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Try engaging the auxillary hydraulics at idle speed or a little faster. With nothing attached to the couplers it should kill the engine or at least make it really labor. It will give you a idea whether or not your pump is working.
Now when I was working with it today, when i lifted the bucket up and started to move forward the oil pressure light briefly went on. This is something that never has happened before, so i think maybe the filter is full or something. I could add that before i bought the machine it has been standing outside without any cover. So when I started to clean the machine there was a lot of dirt everywhere, even in the hydraulic cooler i found small snail shells. Maybee there is a lot of dirt left in the system, i tried to clean it with air to blow out everything. I'll try to change the filter. This is the only thing that could make the oilpressure to drop. But I think the motors are done, with the rust and stuff. One more thing: the motors were "stuck" when i got the machine, so the rust has done something with them.... I really appreciate your help guys!
 

antfarmer2

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Oct 28, 2013
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Now when I was working with it today, when i lifted the bucket up and started to move forward the oil pressure light briefly went on. This is something that never has happened before, so i think maybe the filter is full or something. I could add that before i bought the machine it has been standing outside without any cover. So when I started to clean the machine there was a lot of dirt everywhere, even in the hydraulic cooler i found small snail shells. Maybee there is a lot of dirt left in the system, i tried to clean it with air to blow out everything. I'll try to change the filter. This is the only thing that could make the oilpressure to drop. But I think the motors are done, with the rust and stuff. One more thing: the motors were "stuck" when i got the machine, so the rust has done something with them.... I really appreciate your help guys!
Filters are the first thing to do was the dirt and snails in the fluid?
 

jerry

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Filters are the first thing to do was the dirt and snails in the fluid?
Yes, filters are the first thing to do, on that machine if you raise the boom rapidly and move forward same time you may see the light flicker. If you put a gauge on it and drop the boom while moving you usually see a increase in charge pressure.
 

jerry

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Yes, filters are the first thing to do, on that machine if you raise the boom rapidly and move forward same time you may see the light flicker. If you put a gauge on it and drop the boom while moving you usually see a increase in charge pressure.
The oil can get pretty hot, I think the new Holland light comes on at around 150 f.
 

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