A 743 in pieces

[Tazza]

Looks awlful GOOD to me Tazza! I really like the pump color. I've never pulled an engine yet and am wondering how hard it is to connect the drive coupling back up to the pumps as the engine is going back in. Not much room in the back to guide it back together as it goes in I "assume". Wondering if it takes two people, one up front and the other in the back.
And by the way, it looks like the html button you told me about does the trick for paragraphs! Thanks.

Re-installing the engine is indeed a 2 person job.
One person stays at the back with bars to jiggle the engine forward SLOWLY. You lay down over they hydro pump, put your arm through to the back to the pump and get the person to slowly push it forward to engage the drive coupling. You may need to rotate the engine a small amount to get them to line up. Its really not a fun job but its needed. I haven't attached the stuff to the pump that centres it so i hope it will give me a little more room. I have done this a few times, it gets easier the more times you do it.
One hint to remove the engine, get 2 milk crates and lay a sheet of 1/4" steel over the top, sit it at the back of the machine and slide it out, the milk crates are just about the rite height. If you have a chain block you can lift it out that way too, i have an air powered one that makes it so much easier.
When re-installing it, make sure you grease the universal joint and grease the spline on the pump.
As for the pump colour, that was some paint i got for another project, its not the same as the origional but i don't care, its blue.
If there is anything you need to know about installing the engine in more detail just let me know.

 

[Tigerotor77W]

Re-installing the engine is indeed a 2 person job.
One person stays at the back with bars to jiggle the engine forward SLOWLY. You lay down over they hydro pump, put your arm through to the back to the pump and get the person to slowly push it forward to engage the drive coupling. You may need to rotate the engine a small amount to get them to line up. Its really not a fun job but its needed. I haven't attached the stuff to the pump that centres it so i hope it will give me a little more room. I have done this a few times, it gets easier the more times you do it.
One hint to remove the engine, get 2 milk crates and lay a sheet of 1/4" steel over the top, sit it at the back of the machine and slide it out, the milk crates are just about the rite height. If you have a chain block you can lift it out that way too, i have an air powered one that makes it so much easier.
When re-installing it, make sure you grease the universal joint and grease the spline on the pump.
As for the pump colour, that was some paint i got for another project, its not the same as the origional but i don't care, its blue.
If there is anything you need to know about installing the engine in more detail just let me know.

Wow wow wow wow WOW! Very nice...

 

[Tazza]

Wow wow wow wow WOW! Very nice...

If all goes well, i will install the engine on saturday, as i have just received the new blower housing. Then i can start attaching more bits. I am still of 2 minds of weather to run it without the rams attached to check the hydrostatic system or wait and get it all done and have the rams all attached. I still have quite a bit of work to do on the lift arms, i am trying to hunt down a cheap plasma cutter to gouge out the cracks so i can fill them back up with a nice weld.
Depending on how things go, i will be just that much closer to having a working machine!
Piccies will follow as i get more done.

 

[Blaine]

If all goes well, i will install the engine on saturday, as i have just received the new blower housing. Then i can start attaching more bits. I am still of 2 minds of weather to run it without the rams attached to check the hydrostatic system or wait and get it all done and have the rams all attached. I still have quite a bit of work to do on the lift arms, i am trying to hunt down a cheap plasma cutter to gouge out the cracks so i can fill them back up with a nice weld.
Depending on how things go, i will be just that much closer to having a working machine!
Piccies will follow as i get more done.

You have done an incredible job! I can't imagine doing all of the work that you are. I bought my Deere with the motor and hydraulics all out. I finally got it running last week. I just can't imagine having torn it down more and dealing with that. Look forward seeing more pics

 

[Tazza]

You have done an incredible job! I can't imagine doing all of the work that you are. I bought my Deere with the motor and hydraulics all out. I finally got it running last week. I just can't imagine having torn it down more and dealing with that. Look forward seeing more pics

They really aren't that complicated. This is an older machine so its all mechanical, no electronics to worry about, just a bit of electrical stuff.
The main headache is waiting on pieces. You have to put say the engine in, but you need a piece that goes behind it first.
My main problem now is painting bits, i have a few pieces i need to do but i am using 2 pack paint, so i mix up a bit to paint a few pieces and have to waste what is left. THEN i find out another piece needed doing too, its most frustrating.
I'm just hoping that it will all work when back together, i don't know what the hydrostatics were like when i got it, its really scaring me.... I did have it moving before i pulled it down, but running at idle and it did move so fingers crossed.....
I will have to take piccies of the lift arms before i start on them, they are in a terrible state.

 

[Tazza]

They really aren't that complicated. This is an older machine so its all mechanical, no electronics to worry about, just a bit of electrical stuff.
The main headache is waiting on pieces. You have to put say the engine in, but you need a piece that goes behind it first.
My main problem now is painting bits, i have a few pieces i need to do but i am using 2 pack paint, so i mix up a bit to paint a few pieces and have to waste what is left. THEN i find out another piece needed doing too, its most frustrating.
I'm just hoping that it will all work when back together, i don't know what the hydrostatics were like when i got it, its really scaring me.... I did have it moving before i pulled it down, but running at idle and it did move so fingers crossed.....
I will have to take piccies of the lift arms before i start on them, they are in a terrible state.

ROTTEN THING!!!
Ok, i had plans to install the engine today, the fan housing is in and other bits i needed are ready. So i drag the engine out, i then get the universal joint to attach to the fly wheel and proceed to grease it. The first grease nipple worked fine, grease squirted out where it should, then the second one refused to put any grease out. I poke and prod it a bit and notice its not moving in one direction!, then take a closer look and its sitting at a funny angle. It has worn so badly that the needle rollers have all been broken up and fused on one side. Just what i needed..... All i wanted to do was get the rotten engine in so i could get oil moving around, but it just wasn't to be.....
I'm dredding what Bobcat will charge for the universal joints....
So, thats where i am at. I still have alot to do, but getting the time is becoming harder and harder. Hopefully i will do a little poking around with the lift arms tomorrow and i'll try to get piccies of the dodgy repair that the previous owner did. I need to remove the old bosses and weld new ones on, then attach it to the machine so i can pull it into shape and weld it so its actually straight. I have ordered 5m of 41/40 bar to make my pins and bushings, which i will need to get hardened after maching.

 

[skidsteer.ca]

ROTTEN THING!!!
Ok, i had plans to install the engine today, the fan housing is in and other bits i needed are ready. So i drag the engine out, i then get the universal joint to attach to the fly wheel and proceed to grease it. The first grease nipple worked fine, grease squirted out where it should, then the second one refused to put any grease out. I poke and prod it a bit and notice its not moving in one direction!, then take a closer look and its sitting at a funny angle. It has worn so badly that the needle rollers have all been broken up and fused on one side. Just what i needed..... All i wanted to do was get the rotten engine in so i could get oil moving around, but it just wasn't to be.....
I'm dredding what Bobcat will charge for the universal joints....
So, thats where i am at. I still have alot to do, but getting the time is becoming harder and harder. Hopefully i will do a little poking around with the lift arms tomorrow and i'll try to get piccies of the dodgy repair that the previous owner did. I need to remove the old bosses and weld new ones on, then attach it to the machine so i can pull it into shape and weld it so its actually straight. I have ordered 5m of 41/40 bar to make my pins and bushings, which i will need to get hardened after maching.

Take you ujoint down to a industrial supplier and see if they can cross it or measure it up. The ones on my 553 just look like a common mechanix style (held on by 8 bolt) and I'm sure they are used on more then a 553, your 743 probably is not the only machine to use that joint either. I used chrome cylinder shafting for pins, very hard on the outside and tough ( had to grind in a 1/10 of a inch on each side to drill hole to put the bolt through) We used this for some pins on my wood loader and they have held up very well. to soon to tell on the 553, only 75 hours on it now. Ken

 

[Tazza]

Take you ujoint down to a industrial supplier and see if they can cross it or measure it up. The ones on my 553 just look like a common mechanix style (held on by 8 bolt) and I'm sure they are used on more then a 553, your 743 probably is not the only machine to use that joint either. I used chrome cylinder shafting for pins, very hard on the outside and tough ( had to grind in a 1/10 of a inch on each side to drill hole to put the bolt through) We used this for some pins on my wood loader and they have held up very well. to soon to tell on the 553, only 75 hours on it now. Ken

Exactly, my dad knows a bearing place that can get all that sort of stuff. We are going to try him first as they can't be made JUST for a bobcat (i hope). Alot of the parts can be sourced from else where at good prices.
As for chrome bar, the chrome plating is so very thin it won't do much, unless you go for induction hardened chrome bar, its a horror to drill and cut, but its ideal for pins. Its hard about 1/8" deep. Don't get me wrong, standard chrome bar does the job, i have used it on my 731, but i want my pins to last on the 743, so i am going to nitride both the pins and bushes so hopefully i will never need to replace them.
Standard chrome bar marks so easily its not funny, when i was making new sticks for my 4 in 1 bucket i had a tiny piece of swarf that put a dent in the bar *sad face here*.

 

[skidsteer.ca]

Exactly, my dad knows a bearing place that can get all that sort of stuff. We are going to try him first as they can't be made JUST for a bobcat (i hope). Alot of the parts can be sourced from else where at good prices.
As for chrome bar, the chrome plating is so very thin it won't do much, unless you go for induction hardened chrome bar, its a horror to drill and cut, but its ideal for pins. Its hard about 1/8" deep. Don't get me wrong, standard chrome bar does the job, i have used it on my 731, but i want my pins to last on the 743, so i am going to nitride both the pins and bushes so hopefully i will never need to replace them.
Standard chrome bar marks so easily its not funny, when i was making new sticks for my 4 in 1 bucket i had a tiny piece of swarf that put a dent in the bar *sad face here*.

It was the induction hardened, that why we had grind it in the spot (both sides) where the bolt hole was drilled ken

 

[sterlclan]

It was the induction hardened, that why we had grind it in the spot (both sides) where the bolt hole was drilled ken

If you mix too much two part paint put it in a clean airtight PLASTIC container (tupperware if the wife wont miss it)tape the lid shut and put it in the fridge you may get two days before it starts to kick if it gets too thick to spray throw it out. used to save the last bits from painting big rigs for the inevitable ding in re assembly Good Job by the way Jeff

 

[Tazza]

If you mix too much two part paint put it in a clean airtight PLASTIC container (tupperware if the wife wont miss it)tape the lid shut and put it in the fridge you may get two days before it starts to kick if it gets too thick to spray throw it out. used to save the last bits from painting big rigs for the inevitable ding in re assembly Good Job by the way Jeff

Thanks for the tip, unfortunatly i'm too lazy to get the paint out of the gun fast enough. By the time i finish the paint is already thickening...
Most of the time i manage to measure it out pretty well, only a small amount of wastage, but i will definatly do that in future.
My dad has found the universal joints, or spiders as they are also known. When i have them in my hand i will post the numbers, this way i can be 100% sure they are the rite ones. Bobcat want about 140 each for them plus tax. So far the best we have is about $45 each, working on doing better than this, a few other places to try.

 

[Tazza]

Thanks for the tip, unfortunatly i'm too lazy to get the paint out of the gun fast enough. By the time i finish the paint is already thickening...
Most of the time i manage to measure it out pretty well, only a small amount of wastage, but i will definatly do that in future.
My dad has found the universal joints, or spiders as they are also known. When i have them in my hand i will post the numbers, this way i can be 100% sure they are the rite ones. Bobcat want about 140 each for them plus tax. So far the best we have is about $45 each, working on doing better than this, a few other places to try.

The engine is in!!!!
I made caps for the tube lines as i have no rams attached yet. Installed the engine and fired it up, it made awfull grinding sound and there was what looked like white dust was blowing out of the radiator. The fins on the fly wheel were touching one spot on the fan housing wearing a piece off, causing small pieces of plastic to blow out the radiator fins. After much cursing i pulled the engine back and installed a spacer to push the housing forward just enough. I started it again and there were no grinding sounds, the engine was purring like a kitten, well as much as a diesel can *tap tap tap tap*.
The hydro pump seems to be heating up a bit fast for my liking, i think there is still a bit of air traped in the system. I'm not sure if it is because i have no rams attached so there is no oil flowing through the spool valve or not.... I did manage to push the top spool in that controls the lift section and it made a horrible sound which i think is just air. I have removed the centring parts off the hydro pump (i need to make a few parts to fix it) and i just have the arms sitting on the pump so i could just push or pull them to move the wheels.
So far so good, the wheels turn, the engine starts, nothing belw up so all in all, i think things are going well. Hopefully i won't have any more big expenses to finish the job, apart from the bits i need from bobcat like rubber bushings, temp sender, o/flow bottle plus more small items.
I STILL haven't gotten to work on the lift arms, i am waiting on some 41/40 steel to make pins and bushes so i can put the arms on the machine and pull them straight so i can put the rams on!
Pictures will follow when i get a chance to take some, i think its looking pretty good, bare but good.

 

[skidsteer.ca]

The engine is in!!!!
I made caps for the tube lines as i have no rams attached yet. Installed the engine and fired it up, it made awfull grinding sound and there was what looked like white dust was blowing out of the radiator. The fins on the fly wheel were touching one spot on the fan housing wearing a piece off, causing small pieces of plastic to blow out the radiator fins. After much cursing i pulled the engine back and installed a spacer to push the housing forward just enough. I started it again and there were no grinding sounds, the engine was purring like a kitten, well as much as a diesel can *tap tap tap tap*.
The hydro pump seems to be heating up a bit fast for my liking, i think there is still a bit of air traped in the system. I'm not sure if it is because i have no rams attached so there is no oil flowing through the spool valve or not.... I did manage to push the top spool in that controls the lift section and it made a horrible sound which i think is just air. I have removed the centring parts off the hydro pump (i need to make a few parts to fix it) and i just have the arms sitting on the pump so i could just push or pull them to move the wheels.
So far so good, the wheels turn, the engine starts, nothing belw up so all in all, i think things are going well. Hopefully i won't have any more big expenses to finish the job, apart from the bits i need from bobcat like rubber bushings, temp sender, o/flow bottle plus more small items.
I STILL haven't gotten to work on the lift arms, i am waiting on some 41/40 steel to make pins and bushes so i can put the arms on the machine and pull them straight so i can put the rams on!
Pictures will follow when i get a chance to take some, i think its looking pretty good, bare but good.

Glad to hear she runs. On a open center hyd system the pump shoud circulate oil throught the valve valve and back to the tank, purging any air. --------------------------------------------------------------------------------------------------------------If you join your cylinder line together, you can operate the foot pedals and purge them too, but the cylinders still have to be connected anyway-------------------------------------------------------------------------------------------------------------With your lines blocked, when you activated the top spool the relief valve should have opened, one that was likely the noise you heard, was the system coming to full pressure then the relief opening at 2000 psi or where ever it is .-------------------------------------------------------------------------------------------------------------------------- Hopefully the relief valve is set properly. My 553 was set way to high and would nearly stall the motor when a cylinder hit the end. I would check yours when you have a chancee, just to be safe. Some people tweek these for a more powerful lift,,etc. But if its too high something is going to burst.------------------------------------------------------------------------------------------------------------------------- My 553 is factory set @ 1600 psi, local teck said they go to 2000 for a little more umph. Mine turned out to be 3000. Its a wonder the pump didn't split or something.-------------------------------------------------------------------------------------------------------------------------------- Hearing her huming again must feel good.... Ken

 

[Tazza]

Glad to hear she runs. On a open center hyd system the pump shoud circulate oil throught the valve valve and back to the tank, purging any air. --------------------------------------------------------------------------------------------------------------If you join your cylinder line together, you can operate the foot pedals and purge them too, but the cylinders still have to be connected anyway-------------------------------------------------------------------------------------------------------------With your lines blocked, when you activated the top spool the relief valve should have opened, one that was likely the noise you heard, was the system coming to full pressure then the relief opening at 2000 psi or where ever it is .-------------------------------------------------------------------------------------------------------------------------- Hopefully the relief valve is set properly. My 553 was set way to high and would nearly stall the motor when a cylinder hit the end. I would check yours when you have a chancee, just to be safe. Some people tweek these for a more powerful lift,,etc. But if its too high something is going to burst.------------------------------------------------------------------------------------------------------------------------- My 553 is factory set @ 1600 psi, local teck said they go to 2000 for a little more umph. Mine turned out to be 3000. Its a wonder the pump didn't split or something.-------------------------------------------------------------------------------------------------------------------------------- Hearing her huming again must feel good.... Ken

The sound wasn't the usual whistle that the relief valve makes, it was more of a grind like from cavetation. I will throw a gauge on the hydraulic lines when i have them attached and check the pressure. The vickers pumps can provide about 3,000 PSI but thats getting close to their rated maximum. My hoses are rated to about 2,700 PSI so i really don't want it to have been set too high. Almost double the factory pressure is just insane! that would have been very dangerous as your hoses wouldn't have been rated for that!
As for linking the cylinder lines, i don't have any fittings and hose to do this, so i will just have to leave it as it is untill i get the arms done and install the rams.

 

[Tazza]

The sound wasn't the usual whistle that the relief valve makes, it was more of a grind like from cavetation. I will throw a gauge on the hydraulic lines when i have them attached and check the pressure. The vickers pumps can provide about 3,000 PSI but thats getting close to their rated maximum. My hoses are rated to about 2,700 PSI so i really don't want it to have been set too high. Almost double the factory pressure is just insane! that would have been very dangerous as your hoses wouldn't have been rated for that!
As for linking the cylinder lines, i don't have any fittings and hose to do this, so i will just have to leave it as it is untill i get the arms done and install the rams.

Piccie with the engine in:

Note the jack under the back, the back wheels are up on jack stands and a jack is under the front but with no bucket or lift arms all the weight is in the back. Without the jack under the back, you can lift the front by hand! I hope that made a little sense.....
As you can see the engine has been sitting for a little while, a nice layer of dust is on it....

 

[Tazza]

Piccie with the engine in:

Note the jack under the back, the back wheels are up on jack stands and a jack is under the front but with no bucket or lift arms all the weight is in the back. Without the jack under the back, you can lift the front by hand! I hope that made a little sense.....
As you can see the engine has been sitting for a little while, a nice layer of dust is on it....

I'm convinced that there is air trapped in the hydrostatic system. I can grab a wheel and turn it and the hydro motor moves, which when full of oil shouldn't budge!
All i can think of is that i have no load on the motors so there is not enough leakage through the case drain to bleed the system..... I can remove the allen screw on top on the hydro pump and there are bubbles coming out when the machine isn't running. When i get the parts needed for the steering linkages i will load it down and see if that clears up the problems.
Does anyone know a better way to purge the air from the hydrostatic system? as its a closed loop but with a case drain that allows fresh cooled oil to enter the curcuit. Where is goodtech when you need him! I probably shouldn't be starting it much untill i can load it down, as the engine is fully re-conditioned and they need to be loaded down and run at all over the rev range to run in correctly. I have been told that just running them without a load doesn't allow them to wear in correctly. I have run it for maybee 10 mins total over a few starts.

 

[siduramaxde]

I'm convinced that there is air trapped in the hydrostatic system. I can grab a wheel and turn it and the hydro motor moves, which when full of oil shouldn't budge!
All i can think of is that i have no load on the motors so there is not enough leakage through the case drain to bleed the system..... I can remove the allen screw on top on the hydro pump and there are bubbles coming out when the machine isn't running. When i get the parts needed for the steering linkages i will load it down and see if that clears up the problems.
Does anyone know a better way to purge the air from the hydrostatic system? as its a closed loop but with a case drain that allows fresh cooled oil to enter the curcuit. Where is goodtech when you need him! I probably shouldn't be starting it much untill i can load it down, as the engine is fully re-conditioned and they need to be loaded down and run at all over the rev range to run in correctly. I have been told that just running them without a load doesn't allow them to wear in correctly. I have run it for maybee 10 mins total over a few starts.

Tazza, I know that when I get air in my mower hydros I have to put the mower up on jacks, Put the control levers in the forward position, then I have to manually turn the wheels by hand for awhile till they start moving on their own. It takes awhile to get all the air out but it usually works it's way out. I'm not sure if this method would work on a bobcat. Goodluck.

 

[Tazza]

Tazza, I know that when I get air in my mower hydros I have to put the mower up on jacks, Put the control levers in the forward position, then I have to manually turn the wheels by hand for awhile till they start moving on their own. It takes awhile to get all the air out but it usually works it's way out. I'm not sure if this method would work on a bobcat. Goodluck.

Just a small update, i have re-welded the lift arms, there were no less that 1m worth of stress cracks that i gouged out with the plasma cutter and re-welded with low hydrogen rods for deep weld penetration. I then did a pass ofer the top of them with a good quality self leveling rod to *pretty* it up. The previous owners shoddy weld job of the right hand arm has been straightened and re-welded, also with low hydrogen rods.
New bosses have been put on the arms, i also replaced the bush at the top pivot point on the arms where they join to the machine.
Now, the fun part! the previous owner in all his wisdom saw fit to drill out where the tapered pins join the the arms to hold the bobtach on. He got a 1 1/4" drill bit and drilled through the arms, and he also drilled the bobtach and threw a 1 1/4" bolt through it!. This wasn't THAT much of a problem if it didn't wear egg shape. I have fixed the arms by machining a tapered sleeve that i put in place and welded into position with a handy jig to kep both sides in perfect allignment. My next fun job will be to fix the bobtach......
I still have no rams attached, but i'm close to re-assembling the lift arm rams, i have more bushes and bosses to make for the 2 rams so i can weld the sticks to them. Its all taking so much time to do, as every bush and pin i need i have to make 2, 1 to get hardened and 1 to put on the machine as a tempory fix to get it together. I'm sure you all know how it is, too much to do and no time to do it!
I'll post more info as it gets completed, i just really need to get it together to give it a good run to run the engine in. The engine has really black oily stuff coming out the exhaust which i hope is just because it hasn't been run in, when i run the machine to move it, its only at idle so i really hope thats all it is. I can't run it in untill i can put it under load, as diesel's will carbon up badly if you don't load them down.

 

[[email protected]]

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.

just wondering how to access your site to view pictures,your answers to this site have saved me alot of money,keep up the awsome work. vince miele

 

[Tazza]

just wondering how to access your site to view pictures,your answers to this site have saved me alot of money,keep up the awsome work. vince miele

I ran out of space on my home page so pictures get put on there but deleted over time to make room for others. If there is anything specific you need, i may have piccies on my computer.