Hello all :)

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KCpaul

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Mar 23, 2015
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G'day. Paul from Southwest Victoria, Australia. I've just bought a Bobcat 631 so I've joined the forum to see what I can find out about these beasts :) I have yet to pick it up and only got to have a quick look at it this morning but it has been re-powered at some stage with a water cooled Isuzu engine. It has apparently been sitting for several years and was running when it was parked up but when it was started the other day the engine ran OK but they only got a bit of a "wiggle" from the drive wheels so it was sold cheap. Hopefully I can get it running without too much hassle. I'll be picking it up early next week so in the mean time I'm reading lots of threads here, trying to get hold of manuals and planning how to attack fault finding it. First step will be to fit a new battery, locate all the filters, make sure they are clean and take it from there I guess. I will be doing a complete fluid change but don't want to do it if I am going to have to drain the oil again to repair something so I would like to get it moving first. I'll start a new thread in the appropriate forum once I have picked it up and have more of an idea what I am looking at. Cheers. Paul
 

Tazza

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Welcome to the site, i'm from Brisbane.
Good plan to start, there may be a hidden filter on this machine. Look on top of the hydraulic pump, there should be a square block, behind the middle fitting on the left should be a bronze filter. This filter causes a lack of drive power but the lift/tilt work just fine.
 
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KCpaul

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Mar 23, 2015
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Welcome to the site, i'm from Brisbane.
Good plan to start, there may be a hidden filter on this machine. Look on top of the hydraulic pump, there should be a square block, behind the middle fitting on the left should be a bronze filter. This filter causes a lack of drive power but the lift/tilt work just fine.
I've found a 632 parts manual on line which I would imagine would be close enough for my needs and that shows the bronze hidden filter so I am assuming mine has one as well. I'd be stoked if it was that easy but not counting my chickens just yet.
 

Tazza

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I've found a 632 parts manual on line which I would imagine would be close enough for my needs and that shows the bronze hidden filter so I am assuming mine has one as well. I'd be stoked if it was that easy but not counting my chickens just yet.
I had a 731, slightly larger frame and possibly the same engine, a 2 cylinder deutz air cooled.
The engine is very noisy and rattles, but starts really easily if you use the excess fuel button on the pump for cold weather starting.
That bronze filter causes drive issues, if it's plugged it will run ok for a little while then start to loose power. The pump screams and gets hot, eventually it will not have the power to go up a hill or turn.
See how you go, if you have issues, look up my profile and send me an email. Sadly i know more about my ex 731 than i probably should do.
 
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KCpaul

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Mar 23, 2015
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I had a 731, slightly larger frame and possibly the same engine, a 2 cylinder deutz air cooled.
The engine is very noisy and rattles, but starts really easily if you use the excess fuel button on the pump for cold weather starting.
That bronze filter causes drive issues, if it's plugged it will run ok for a little while then start to loose power. The pump screams and gets hot, eventually it will not have the power to go up a hill or turn.
See how you go, if you have issues, look up my profile and send me an email. Sadly i know more about my ex 731 than i probably should do.
Thanks for the offer Tazza. If I get really desperate I'll get in touch :) I've managed to sort out most the issues with the non functioning hydraulics on my tractor in the past so hopefully I should be able to do the same with the Bobcat. I suspect it would have had the same Deutz engine in the past but it now apparently has an Isuzu. I won't know for sure until I get it home and clean off who knows how many years of oil, grease dirt and cow crap :)
 

Tazza

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Thanks for the offer Tazza. If I get really desperate I'll get in touch :) I've managed to sort out most the issues with the non functioning hydraulics on my tractor in the past so hopefully I should be able to do the same with the Bobcat. I suspect it would have had the same Deutz engine in the past but it now apparently has an Isuzu. I won't know for sure until I get it home and clean off who knows how many years of oil, grease dirt and cow crap :)
Ahh, it may have been repowered. Possibly with even more power.
Get it home and clean, hopefully it won't be a hard job to get going well again.
 
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KCpaul

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Mar 23, 2015
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After re-reading you said it has an isuzu water cooled engine, i need to re-read things before i comment it seems :)
The old girl arived today, turns out none of the hydraulics were working. Also turns out hydraulics don't work when there is no oil in the reservoir :). Put in a new battery, topped up the oil and off it went. Needs new bushes in all the control linkages as everything is pretty sloppy. Right hand drive motor is noisy, I have a feeling all the oil is ending up in the chain case through that motor, I havn't pulled the level plug to see but I reckon that's where it will be. Possibly a bad bearing and seal on that motor as I get a bit of a noisy grinding noise when I push on the right stick. Thoughts?
 

Tazza

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The old girl arived today, turns out none of the hydraulics were working. Also turns out hydraulics don't work when there is no oil in the reservoir :). Put in a new battery, topped up the oil and off it went. Needs new bushes in all the control linkages as everything is pretty sloppy. Right hand drive motor is noisy, I have a feeling all the oil is ending up in the chain case through that motor, I havn't pulled the level plug to see but I reckon that's where it will be. Possibly a bad bearing and seal on that motor as I get a bit of a noisy grinding noise when I push on the right stick. Thoughts?
The drive motors won't have seals like you think, the seal is on the chain case. Try running it a bit to get the air out before condeming the motor.
If oil is going into the chain case, it could be either of the seals, don't think just because one motor is making noise, that it is the cause.
Have a look at this link, it's not the same model machine, but it shows the seals to the chaincase. This video is made by the guy that started up loader parts source.
http://www.loaderpartssource.com/kbase/Videos/Bobcat_S130_Drive_Motor_Install.html
 
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KCpaul

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Mar 23, 2015
Messages
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The drive motors won't have seals like you think, the seal is on the chain case. Try running it a bit to get the air out before condeming the motor.
If oil is going into the chain case, it could be either of the seals, don't think just because one motor is making noise, that it is the cause.
Have a look at this link, it's not the same model machine, but it shows the seals to the chaincase. This video is made by the guy that started up loader parts source.
http://www.loaderpartssource.com/kbase/Videos/Bobcat_S130_Drive_Motor_Install.html
I think the older models like mine have the seals on the motor, according to the parts book and manual the sprockets and brake disks fit directly to the motor shaft, not on an intermediate shaft as shown on the video. The only seal shown on the chain case is an o-ring that seals the motor to the chain case. I pulled the level plug on the drain case today and milky oil flooded out so I'll need to drain the lot, find out where the water is gettin in, clean out the chain case and re-fill. I still think there's a good chance I have a leaking motor seal, but if I do one side I'll do both.
 

Tazza

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I think the older models like mine have the seals on the motor, according to the parts book and manual the sprockets and brake disks fit directly to the motor shaft, not on an intermediate shaft as shown on the video. The only seal shown on the chain case is an o-ring that seals the motor to the chain case. I pulled the level plug on the drain case today and milky oil flooded out so I'll need to drain the lot, find out where the water is gettin in, clean out the chain case and re-fill. I still think there's a good chance I have a leaking motor seal, but if I do one side I'll do both.
Ah, you have that style of motor, you are right.
As for the milky oil, the chain case covers are 99% of the time the cause. You need to take them off and re-seal with quality silicone. Don't forget the bolt threads either.
 
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