A 743 in pieces

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Tazza

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I have almost finished pulling one of my 743's down to be re-painted, i just need to finish removing the axles to replace the seals

Its amazing just how few parts there actually are, mind you, it will be a big task to re-assemble it all. I have the chain case and main chassis separated, the chain case and axles look like nothing, i swear by looking at them you would never guess it is the basis of such a tough piece of gear.

If anyone wants piccies just yell, i have a few and am always taking more but be warned, these pictures may offend bobcat lovers!

ooh, any who said you don't need a bucket with teeth? mine are a great lifting point to suspend bobcat pieces for cleaning with a pressure washer.
 

ajwgator

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Tazza, I would like the pictures. You know one picture is worth a 1,000 words! In email is just fine. Thanks
 

Tazza

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Tazza, I would like the pictures. You know one picture is worth a 1,000 words! In email is just fine. Thanks
I don't have your e-mail address, so here they are, i have linked them back to my home page.
http://users.tpg.com.au/tazza_/bobcat/120_2089.jpg
http://users.tpg.com.au/tazza_/bobcat/120_2090.jpg
http://users.tpg.com.au/tazza_/bobcat/120_2091.jpg
http://users.tpg.com.au/tazza_/bobcat/120_2092.jpg
http://users.tpg.com.au/tazza_/bobcat/120_2093.jpg
http://users.tpg.com.au/tazza_/bobcat/120_2094.jpg
Just a few, i need to take more as i am closer to painting.
 

ajwgator

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I don't have your e-mail address, so here they are, i have linked them back to my home page.
http://users.tpg.com.au/tazza_/bobcat/120_2089.jpg
http://users.tpg.com.au/tazza_/bobcat/120_2090.jpg
http://users.tpg.com.au/tazza_/bobcat/120_2091.jpg
http://users.tpg.com.au/tazza_/bobcat/120_2092.jpg
http://users.tpg.com.au/tazza_/bobcat/120_2093.jpg
http://users.tpg.com.au/tazza_/bobcat/120_2094.jpg
Just a few, i need to take more as i am closer to painting.
Thanks Tazza. Thought my email addy was in my profile but this is just as good. Look forward to new ones too. Jay W.
 

ajwgator

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Thanks Tazza. Thought my email addy was in my profile but this is just as good. Look forward to new ones too. Jay W.
Hope you don't mind but I went into your sight and checked out some more of the photo's you have. Your right, it is hard to believe how few parts there are for such a tough piece of equipment. Has your cat recovered yet from the hair loss? I can't believe how much your cat looks like a bobcat all shaved like that. Well the wife thought I was surfin porn when she saw the name of the pic. Thanks again for all the info. Jay W.
 

Tazza

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Hope you don't mind but I went into your sight and checked out some more of the photo's you have. Your right, it is hard to believe how few parts there are for such a tough piece of equipment. Has your cat recovered yet from the hair loss? I can't believe how much your cat looks like a bobcat all shaved like that. Well the wife thought I was surfin porn when she saw the name of the pic. Thanks again for all the info. Jay W.
LOL
He has, but he has been shaven again.
The first time he got shaved was because he got beat up by the neighbours cat. He was shaven again reciently because he was beaten up again and because its summer it helps keep long haired cats cool.
He is an ugly cat at the best of times, but after being shaved he looks worse!
 

goodtech

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LOL
He has, but he has been shaven again.
The first time he got shaved was because he got beat up by the neighbours cat. He was shaven again reciently because he was beaten up again and because its summer it helps keep long haired cats cool.
He is an ugly cat at the best of times, but after being shaved he looks worse!
Hey there Tazz that 743 is a very clean lookin machine. It is amazing how simple they are built though. Its just 10 lbs of crap it 3 pound bucket. While you have your lift arms off check for cracks and weld them up also while you have it off it makes life alot easier. Good luck with your project.
 

Tazza

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Hey there Tazz that 743 is a very clean lookin machine. It is amazing how simple they are built though. Its just 10 lbs of crap it 3 pound bucket. While you have your lift arms off check for cracks and weld them up also while you have it off it makes life alot easier. Good luck with your project.
The lift arms were cracked as you said, but the previous owner welded them up, then looks like it was welded again. Its a horror show, there is a steel plate welded to the top and sides, but they never closed up the crack on the underside, so one side sits lower then the other its just a mess. Then the bobtach pins were drilled out and bolts were put in, also the tilt ram, so another joy for me to fix. It is all repairable, it will just take a little while to complete.
I will keep updating the progress.
Oh, the rear right axle housing where its welded to the chain case had a cracked weld, all 5 bolts where it bolted to the chassis were loose, so if anyone has loose bolts down there, tighten them up!
 

Eric

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The lift arms were cracked as you said, but the previous owner welded them up, then looks like it was welded again. Its a horror show, there is a steel plate welded to the top and sides, but they never closed up the crack on the underside, so one side sits lower then the other its just a mess. Then the bobtach pins were drilled out and bolts were put in, also the tilt ram, so another joy for me to fix. It is all repairable, it will just take a little while to complete.
I will keep updating the progress.
Oh, the rear right axle housing where its welded to the chain case had a cracked weld, all 5 bolts where it bolted to the chassis were loose, so if anyone has loose bolts down there, tighten them up!
From my experience with welding/repairing stress cracks on Bobcats, you really need to brace or bridge the area with some added steel. The reason why there is a crack there is because its the weakest link in the chain. I find that if you just try to grind the crack out and fill it back in with a weld it just doesn't hold up. I say if your gonna spend the time to do a repair, take that extra time to do it right. If your loader arms are cracking in a certain area and you just re-weld it, you didn't really fix the problem. You covered up a symptom of the problem which will more likely return. A stress crack tells me that area needs to be reinforced. The stress crack is a symptom, the true problem is poor materials, poor design, or maybe operator abuse. Some of these Bobcats are to powerful for there own good. In the hands of a bad operator a machine can destroy itself.
 

Tazza

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From my experience with welding/repairing stress cracks on Bobcats, you really need to brace or bridge the area with some added steel. The reason why there is a crack there is because its the weakest link in the chain. I find that if you just try to grind the crack out and fill it back in with a weld it just doesn't hold up. I say if your gonna spend the time to do a repair, take that extra time to do it right. If your loader arms are cracking in a certain area and you just re-weld it, you didn't really fix the problem. You covered up a symptom of the problem which will more likely return. A stress crack tells me that area needs to be reinforced. The stress crack is a symptom, the true problem is poor materials, poor design, or maybe operator abuse. Some of these Bobcats are to powerful for there own good. In the hands of a bad operator a machine can destroy itself.
I agree, i'm pretty sure the previous owner did indeed abuse this poor machine, it looks like it was never given a bath or an oil change. I am still a fair way off doing the lift arms, i want to get the main frame all done up first then attach the arms and straighten and weld them and see where i am at. I may have a line on a spare set of lift arms yet, hopefully these will require much less effort to get up to scratch.
If i do brace the arms, i won't do a shoddy job like what the last user did to the poor thing, but i must admit it seems to have held, just looks ugly.
 

Luthor

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I agree, i'm pretty sure the previous owner did indeed abuse this poor machine, it looks like it was never given a bath or an oil change. I am still a fair way off doing the lift arms, i want to get the main frame all done up first then attach the arms and straighten and weld them and see where i am at. I may have a line on a spare set of lift arms yet, hopefully these will require much less effort to get up to scratch.
If i do brace the arms, i won't do a shoddy job like what the last user did to the poor thing, but i must admit it seems to have held, just looks ugly.
Great pictures Tazza. I will be interseted in your progress as you go about replacing axle seals, especially the rear, as I have a bad leaker on one side of my 743 . Do you happen to know the original paint codes used on these machines? By the way, are we the only Aussies on this forum?
 

Tazza

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Great pictures Tazza. I will be interseted in your progress as you go about replacing axle seals, especially the rear, as I have a bad leaker on one side of my 743 . Do you happen to know the original paint codes used on these machines? By the way, are we the only Aussies on this forum?
I don't know what the origional paint codes are, i am just going white for the frame and black for the rops (pretty sure it is suposed to be charcoal) i will get a colour match of the orange for the rims and door though.
I already have the white two pack paint, i will get some black two pack too and just enamel for the rims and back door. I got the decals for the rear door and lift arms off e-bay.
I think there is 1 other aussie on the forum, maybee more.
As for the seals, i have all the part numbers for the bearings and seals, my dad did some investigating today, i will post details in the general repair section as i have a post there about it. They are ALOT cheaper than i expected.
 

Tazza

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I don't know what the origional paint codes are, i am just going white for the frame and black for the rops (pretty sure it is suposed to be charcoal) i will get a colour match of the orange for the rims and door though.
I already have the white two pack paint, i will get some black two pack too and just enamel for the rims and back door. I got the decals for the rear door and lift arms off e-bay.
I think there is 1 other aussie on the forum, maybee more.
As for the seals, i have all the part numbers for the bearings and seals, my dad did some investigating today, i will post details in the general repair section as i have a post there about it. They are ALOT cheaper than i expected.
Sorry, forgot to talk about your seal. To replace it if it is a rear seal it will be a horrible job. You need to crack the bolt holding the gear inside the chain case, the main problem is getting access to it, you will need to remove your steering levers and housing that they run in. Remove your park brake and remove the assembly that grabs the 2 metal discs. You will need an 1 1/8” ring spanner, as long as possible, get it on the bolt then you need to rotate your axle from the outside while someone holds the spanner while it moves untill it hits the chain case (its so tight you can't hold it by hand).
If you decide you want to give it a go, let me know and i can tell you what you will need to do. Its much easier for me to do as i don't have an access problem, its all in bits :)
The fun part is working out where it all goes, ooh and where to put the left over hoses......
 

goodtech

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Sorry, forgot to talk about your seal. To replace it if it is a rear seal it will be a horrible job. You need to crack the bolt holding the gear inside the chain case, the main problem is getting access to it, you will need to remove your steering levers and housing that they run in. Remove your park brake and remove the assembly that grabs the 2 metal discs. You will need an 1 1/8” ring spanner, as long as possible, get it on the bolt then you need to rotate your axle from the outside while someone holds the spanner while it moves untill it hits the chain case (its so tight you can't hold it by hand).
If you decide you want to give it a go, let me know and i can tell you what you will need to do. Its much easier for me to do as i don't have an access problem, its all in bits :)
The fun part is working out where it all goes, ooh and where to put the left over hoses......
On those lift arms, I usually take and air arc the crack out weld both sides if possible and the plate the area or gussit it. On the 743 they like to crack around the top of the tilt cyc pin and then around the arm the you step on to get into the machine, where they are weld to the lift arms themselves, as for your bobtac mess good luck... I can't remeber off hand if bobcat makes weld on ends for the 743... something else I will have to look into for you.
 

Tazza

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On those lift arms, I usually take and air arc the crack out weld both sides if possible and the plate the area or gussit it. On the 743 they like to crack around the top of the tilt cyc pin and then around the arm the you step on to get into the machine, where they are weld to the lift arms themselves, as for your bobtac mess good luck... I can't remeber off hand if bobcat makes weld on ends for the 743... something else I will have to look into for you.
Don't be too worried about the bobtach pins, i have an idea in my head of what i am going to do, i do have a lathe so i can make new pins and bushes easily. I will then get them hardened.
It appears that it has been welded on the front where the arms go down as there is a big plate across the front which i don't think is stock. Unfortunatly i don't have a plasma cutter which i think you are refering to as an air arc welder, so i will gouge it out with a grinder and lay a hefty weld where the lift arms have cracked. But hopefully i can get an old set of lift arms off a friend but they are cracked too but i think it will require minimal effort to repair. The lift arms are one of the last things i am going to be worring about.
Don't work too hard!
 

Luthor

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Don't be too worried about the bobtach pins, i have an idea in my head of what i am going to do, i do have a lathe so i can make new pins and bushes easily. I will then get them hardened.
It appears that it has been welded on the front where the arms go down as there is a big plate across the front which i don't think is stock. Unfortunatly i don't have a plasma cutter which i think you are refering to as an air arc welder, so i will gouge it out with a grinder and lay a hefty weld where the lift arms have cracked. But hopefully i can get an old set of lift arms off a friend but they are cracked too but i think it will require minimal effort to repair. The lift arms are one of the last things i am going to be worring about.
Don't work too hard!
Tazza, I hope the holes in you bobtach are not too badly worn, mine were really flogged out and I had to bore them about 1/4" oversize and make new bushes to suit. I also made 2 sets of new pins and 1/8" thick shims to go between lift arms and bobtach so now I have little or no movement at that point.
 

Tazza

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Tazza, I hope the holes in you bobtach are not too badly worn, mine were really flogged out and I had to bore them about 1/4" oversize and make new bushes to suit. I also made 2 sets of new pins and 1/8" thick shims to go between lift arms and bobtach so now I have little or no movement at that point.
The holes *look* round, but i have just ordered a few drill bits so i can take them out to the rite size and make pins and bushes to suit. they drilled a hole rith through the lift arms and the bobtach bush, its about 1 1/4”, so there is no taper like it should have. I have plan of how to repair this, its just alot of fiddling. All the pins will be hardened and all the moving joints will be bored out and bushed with replaceable hardened bushes. So when things wear i just knock out the old bushes and pins and replace and its perfect, no boring or reaming required afterwards.
I picked up a heap of O rings to replace on the control block today, so that will be done soon, all of $10 worth of O rings, i would hate to think of how much they are genuine.....
 

goodtech

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The holes *look* round, but i have just ordered a few drill bits so i can take them out to the rite size and make pins and bushes to suit. they drilled a hole rith through the lift arms and the bobtach bush, its about 1 1/4”, so there is no taper like it should have. I have plan of how to repair this, its just alot of fiddling. All the pins will be hardened and all the moving joints will be bored out and bushed with replaceable hardened bushes. So when things wear i just knock out the old bushes and pins and replace and its perfect, no boring or reaming required afterwards.
I picked up a heap of O rings to replace on the control block today, so that will be done soon, all of $10 worth of O rings, i would hate to think of how much they are genuine.....
The seal kit for the control valve is spendy, but remind you that bobcat makes there own control valves, and the seals are odd ball. Make sure you replace the same color seal with the ones that are in there or you will be doing it again. I've been there and done that one too many times. If I remember right I believe it is the blue seals in the kit fit the 743. They sell the one kit that fits many models, so you have to find the right color. Ive tried to go to the hydraulic shops around here when I'm in a jam, but I'm here to tell you they just don't work, its bit me in the butt. So when it comes to the control valves on the skidsteers or excavators all I will use is bobcat seals, even though the other ones seem like they will work. It may seem like alot of money, but when your redoing it again and having to buy the seals from bobcat..... do it right the first time
 

Tazza

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The seal kit for the control valve is spendy, but remind you that bobcat makes there own control valves, and the seals are odd ball. Make sure you replace the same color seal with the ones that are in there or you will be doing it again. I've been there and done that one too many times. If I remember right I believe it is the blue seals in the kit fit the 743. They sell the one kit that fits many models, so you have to find the right color. Ive tried to go to the hydraulic shops around here when I'm in a jam, but I'm here to tell you they just don't work, its bit me in the butt. So when it comes to the control valves on the skidsteers or excavators all I will use is bobcat seals, even though the other ones seem like they will work. It may seem like alot of money, but when your redoing it again and having to buy the seals from bobcat..... do it right the first time
ALL the seals inside my control block are black....
There are 2 quad rings on each spool which my seal shop didn't have the same width, but we both agreed that using a backup ring on the non pressure side would take up the rest, all the other seals are standard O rings and backup rings of a standard size. I will however need to buy genuine boots that cover the exposed part of the spool.
 
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