project 751 re-build

[Tazza]

Ok, some of you know i'm working on a 751 that got a little burnt... ok, a lot burnt. I finally got a bit of time to pull it down a bit. The engine was pulled a few months back that i got running, the pump i have cleaned and flat plated the swash plates so its good to go.
I did have a few problems with water that was in the chaincase...

I LOVE my 4 in 1, handy for just about every job, especially lifting.

Removing axle hub, this was a LOT harder than i thought it would be. Thats 1 x 12 tonne and 2 x 2 tonne hydraulics jacks! When i put pressure on the axle hub it needed a good bash with a copper hammer to come loose. That one actually flung off and landed square on top of my foot!!!!

Axle hub off

Cracking the bolts inside that hold the sprockets to the axles. The bolts were VERY loose on this machine, should have needed every bit of leverage that pipe had.

Pressing out the axle. This is needed to pull the inner bearing off the axle. Some may pull the outer bearing and seal out too. Put the axle hub back on but leave it loose so it can be easily removed later.

Axles are all out.

Rust on motor carriers. I was worried that the rust got to the bearings, none was there but there was a lot of grit in the axle tubes and the carrier. There was wear on the bearing cups, so they really did need replacing. There was no end play but marks were on the bearing face.

Pressing out the shaft of the carrier. I don't have a press but i managed to get them out with a hydraulic puller.

Here is what the hydraulic motor looks like. Most other machines have the same setup, the motors may be a different brand but are essentially the same. This motor was pulled down due to carbon enetering the system. Good thing i opened it as the backup rings inside were broken. Pictures to follow when i get a seal kit and re-assemble it.

 

[jerry]

Thanks for the pictures and all Tazza, this is interesting reading and certainly a lot of information that people can use on similar projects.

 

[skidsteer.ca]

Thanks for the pictures and all Tazza, this is interesting reading and certainly a lot of information that people can use on similar projects.

Yes , great update, I'll be practicing on my 773 soon as the lr axel seal has started leaking, my own fault to I fear.
Looking forward to a update on the motor. Did you take some pices of the swash plates too?
Ken

 

[Tazza]

Yes , great update, I'll be practicing on my 773 soon as the lr axel seal has started leaking, my own fault to I fear.
Looking forward to a update on the motor. Did you take some pices of the swash plates too?
Ken

I did get pictures of the swash plates. I will try to post them shortly. Ken, you are lucky if you just need to replace axle seals. Crack the axle hub bolts and use jacks like i did. Give the axle hub a good hit and it will release. You can then drill a hole in the seal and use a slide hammer to get the old seal out.

 

[Tazza]

I did get pictures of the swash plates. I will try to post them shortly. Ken, you are lucky if you just need to replace axle seals. Crack the axle hub bolts and use jacks like i did. Give the axle hub a good hit and it will release. You can then drill a hole in the seal and use a slide hammer to get the old seal out.

Ok, more piccies.
This is the pump before, still all greasy...

Here is the problem, note the charge line was burnt up in the fire and this is carbon from the burnt rubber. This has gone throughout the entire system. Its even in the drive motors!

Swash plate is on the left still attached to the valve, part of the rotating group is on the right.

Swash plate again, note the black crud, this is carbon from that rotten hose!

Pistons from the rotating group, plus the bits that allow it all to pivot.

Rotating group all ready to install, just needs those 3 pins and that cupped *thing* seen in the photo above. This is the hardest piece of all to install as it moves around on you. Using thick grease here sure does help.

Swash plate after being flat plated. You can still see a wear mark, its only very small and its in a section that holds no pressure. It shouldn't give me any problems. I could have sanded it down further to get rid of it completely but this mark you can't even feel with a fingernail.

This is what it looked like before!

Pump section back together. Note the O rings, i used grease to hold them in place, oil isn't sticky enough to hold them real well.

I don't have a pic of it all back together though, i may try and take one tonight.
One thing, you may notice that there is a dowel missing from the bottom of this pump section, i got it together and found a dowel of the floor!!! I thought i put a section together without it but thankfully it was the middle section. You need to pay so much attention when working on pumps, so many small things.
Pump back together, needs a coat of paint though. Yes, thats a bob in the background, 2 actually, if you look carefully.

 

[Butters]

Ok, more piccies.
This is the pump before, still all greasy...

Here is the problem, note the charge line was burnt up in the fire and this is carbon from the burnt rubber. This has gone throughout the entire system. Its even in the drive motors!

Swash plate is on the left still attached to the valve, part of the rotating group is on the right.

Swash plate again, note the black crud, this is carbon from that rotten hose!

Pistons from the rotating group, plus the bits that allow it all to pivot.

Rotating group all ready to install, just needs those 3 pins and that cupped *thing* seen in the photo above. This is the hardest piece of all to install as it moves around on you. Using thick grease here sure does help.

Swash plate after being flat plated. You can still see a wear mark, its only very small and its in a section that holds no pressure. It shouldn't give me any problems. I could have sanded it down further to get rid of it completely but this mark you can't even feel with a fingernail.

This is what it looked like before!

Pump section back together. Note the O rings, i used grease to hold them in place, oil isn't sticky enough to hold them real well.

I don't have a pic of it all back together though, i may try and take one tonight.
One thing, you may notice that there is a dowel missing from the bottom of this pump section, i got it together and found a dowel of the floor!!! I thought i put a section together without it but thankfully it was the middle section. You need to pay so much attention when working on pumps, so many small things.
Pump back together, needs a coat of paint though. Yes, thats a bob in the background, 2 actually, if you look carefully.

WOW you are vested in that one! Keep us up to date.

 

[Tazza]

WOW you are vested in that one! Keep us up to date.

LOL
Its scary, i keep thinking i should get it complete for X amount, then i find something else that needs work. Like bearings, cups and cones for the axles are $200. Bearings for the motor carriers are $200 then i need axle seals but the prices i have gotten so far is all of $6 each (not the brand i would like, so i need to look into OEM for these). I then need a cup seal for the carrier, this may be bobcat only. The motor i believe will be bobcat only as well! so after i opened the chain case, it just added $200 to the bill, now motors! But i still figure its best to spend the money now then i know its rite than having to pull it all down later to fix it.
Thankfully i haven't found anything major wrong. I'm at the point where i will be waiting on parts to continue. I am also going to look into getting almost everything sand blasted, this will also take time but save me a lot of time with a grinder and buffing wheel.

 

[Tazza]

LOL
Its scary, i keep thinking i should get it complete for X amount, then i find something else that needs work. Like bearings, cups and cones for the axles are $200. Bearings for the motor carriers are $200 then i need axle seals but the prices i have gotten so far is all of $6 each (not the brand i would like, so i need to look into OEM for these). I then need a cup seal for the carrier, this may be bobcat only. The motor i believe will be bobcat only as well! so after i opened the chain case, it just added $200 to the bill, now motors! But i still figure its best to spend the money now then i know its rite than having to pull it all down later to fix it.
Thankfully i haven't found anything major wrong. I'm at the point where i will be waiting on parts to continue. I am also going to look into getting almost everything sand blasted, this will also take time but save me a lot of time with a grinder and buffing wheel.

Got 2 prices on sandblasting today..... I think its time to try and build my own sand blaster!
Assembled pump has been added.

 

[triad]

Got 2 prices on sandblasting today..... I think its time to try and build my own sand blaster!
Assembled pump has been added.

Great post Tazza, I think you should document as much as possible I could see a book in the making. Who knows might help with the cost of parts. "Skidsteer repair and rebuild " I'd buy at least one. Steve

 

[skidsteer.ca]

Got 2 prices on sandblasting today..... I think its time to try and build my own sand blaster!
Assembled pump has been added.

Tazza
You could build you own out of a old lpg tank. Buy a hose and some ceramic nozzels, a few valves and air dryer. You will have a better blaster then the boughten ones.
But the blaster is the cheap part. Its the 25 cfm or larger compressor that costs. I have a 27 cfm at 175psi (truck mount 12.5 hp kohler) and that has just enough air imo. Since I got a 18 cfm running in the shop, I now twin the two together. If pressure drops much under 100 , you just wasting sand. Even twined about 130 is where it levels off to. With the 27 when the nozzle got worn oversized, I had trouble maintaining 100 psi.
Most of the small portable blaster over here seriously underate the compressor required.

 

[sterlclan]

Tazza
You could build you own out of a old lpg tank. Buy a hose and some ceramic nozzels, a few valves and air dryer. You will have a better blaster then the boughten ones.
But the blaster is the cheap part. Its the 25 cfm or larger compressor that costs. I have a 27 cfm at 175psi (truck mount 12.5 hp kohler) and that has just enough air imo. Since I got a 18 cfm running in the shop, I now twin the two together. If pressure drops much under 100 , you just wasting sand. Even twined about 130 is where it levels off to. With the 27 when the nozzle got worn oversized, I had trouble maintaining 100 psi.
Most of the small portable blaster over here seriously underate the compressor required.

Tazza do a search on mbn I saw someone there would mail you pdf files on just the unit ken described worth a shot Jeff

 

[Tazza]

Tazza
You could build you own out of a old lpg tank. Buy a hose and some ceramic nozzels, a few valves and air dryer. You will have a better blaster then the boughten ones.
But the blaster is the cheap part. Its the 25 cfm or larger compressor that costs. I have a 27 cfm at 175psi (truck mount 12.5 hp kohler) and that has just enough air imo. Since I got a 18 cfm running in the shop, I now twin the two together. If pressure drops much under 100 , you just wasting sand. Even twined about 130 is where it levels off to. With the 27 when the nozzle got worn oversized, I had trouble maintaining 100 psi.
Most of the small portable blaster over here seriously underate the compressor required.

The thing is, when you are really getting into it you don't always think about stopping to take pictures.... You think of it after!
I have seen a few on the net, they seem easy enough to make.... The nozzle is the one part i'm not sure about. I don't know how big i can go before i'm trying to drag too much air out. My dads compressor is around 16CFM and i have another one about the 12 CMF mark. I can link both of them to the same line easily so i think i would be ok for air supply. I just need to work out the tank and nozzle. For the amount of blasting i will be doing, i see no reason why i can't build a nozzle. If it wears out quickly i can simply make another.
Ken, do you have any pics of your setup? like how long the nozzle is to accelerate the sand? I have a small hand held one that has a 4" nozzle, works well but no way i would attempt a job like this with a unit that small!!!
I think i have some small propane tanks here, but i'm going to try for the ones they use in cars as i think i can get one. They are close to the size of the ones used on houses.

 

[140mower]

The thing is, when you are really getting into it you don't always think about stopping to take pictures.... You think of it after!
I have seen a few on the net, they seem easy enough to make.... The nozzle is the one part i'm not sure about. I don't know how big i can go before i'm trying to drag too much air out. My dads compressor is around 16CFM and i have another one about the 12 CMF mark. I can link both of them to the same line easily so i think i would be ok for air supply. I just need to work out the tank and nozzle. For the amount of blasting i will be doing, i see no reason why i can't build a nozzle. If it wears out quickly i can simply make another.
Ken, do you have any pics of your setup? like how long the nozzle is to accelerate the sand? I have a small hand held one that has a 4" nozzle, works well but no way i would attempt a job like this with a unit that small!!!
I think i have some small propane tanks here, but i'm going to try for the ones they use in cars as i think i can get one. They are close to the size of the ones used on houses.

Looks good so far Tazza, I'm thinking that patience is the order of the day with this one though. It'll be interesting to see what the final build tally is when you're finished with it as well as how many hours you wind up putting in to make it just right.
Keep up the good work.
Don

 

[Tazza]

Looks good so far Tazza, I'm thinking that patience is the order of the day with this one though. It'll be interesting to see what the final build tally is when you're finished with it as well as how many hours you wind up putting in to make it just right.
Keep up the good work.
Don

Jeff - i did get in touch with a bloke from MBN and he sent me a set of plans, as did another user on here, many thanks for that! I should have access to old gas tanks used on cars, great size and if needed i can cut it down to make it a bit easier to move.
Don - i actually don't dare work out just how many hours i have spent or will be spending on it.... After removing the engine i spent around a day pulling the rest down to where you see it now. It doesn't take that long to strip, its scary just how fast it comes apart. Putting it back together will be a different story though......
My main problem is some parts i had arranged from down south, but making contact with him has been a non event.... He had quite a few parts i needed from a kubota conversion, wiring harness, hoses, covers. Hopefully he will get my e-mails and we can sort things out. Worst case, i'll just have to get it from my dealer.
I spent Sunday building an adapter for a porta power pull ram to seal the axle bearing cups. Works great! install rod, put cups in place, screw end cap on then pump the hydraulic pump and it pulls both in till they seat. So easy, nothing like my 743 using a bar and hammer......

 

[skidsteer.ca]

Jeff - i did get in touch with a bloke from MBN and he sent me a set of plans, as did another user on here, many thanks for that! I should have access to old gas tanks used on cars, great size and if needed i can cut it down to make it a bit easier to move.
Don - i actually don't dare work out just how many hours i have spent or will be spending on it.... After removing the engine i spent around a day pulling the rest down to where you see it now. It doesn't take that long to strip, its scary just how fast it comes apart. Putting it back together will be a different story though......
My main problem is some parts i had arranged from down south, but making contact with him has been a non event.... He had quite a few parts i needed from a kubota conversion, wiring harness, hoses, covers. Hopefully he will get my e-mails and we can sort things out. Worst case, i'll just have to get it from my dealer.
I spent Sunday building an adapter for a porta power pull ram to seal the axle bearing cups. Works great! install rod, put cups in place, screw end cap on then pump the hydraulic pump and it pulls both in till they seat. So easy, nothing like my 743 using a bar and hammer......

Good tip on the porta power, I have a few 12 to 18 pull rams I could use. I can take a few picsf my blaster if you want. Its just a cheap 100 lb unit. screw on top requires a funnel to fill.
The good ones have the funnel built in and a large disc you pull up and the internal pressure holds the plug up against a oring to seal the tank.
Air comes in through a dryer and then Y's into the top of the tank and also down the side and then straight across the bottom. As it crosses the bottom there is a T that points straight up into the bottom of the tank with a ball valve to control the speed the sand in allowed to drop into the air stream. From there the air continues on though 3 meters of heavy wall hose and into a 3.2mm ceramic nozzel with a ball valve to stop the flow. The best nozzles have a heavy square rubber cube that plugs the end of the nozzle to stop the sand. the ball valves don't last long
Ken

 

[Tazza]

Good tip on the porta power, I have a few 12 to 18 pull rams I could use. I can take a few picsf my blaster if you want. Its just a cheap 100 lb unit. screw on top requires a funnel to fill.
The good ones have the funnel built in and a large disc you pull up and the internal pressure holds the plug up against a oring to seal the tank.
Air comes in through a dryer and then Y's into the top of the tank and also down the side and then straight across the bottom. As it crosses the bottom there is a T that points straight up into the bottom of the tank with a ball valve to control the speed the sand in allowed to drop into the air stream. From there the air continues on though 3 meters of heavy wall hose and into a 3.2mm ceramic nozzel with a ball valve to stop the flow. The best nozzles have a heavy square rubber cube that plugs the end of the nozzle to stop the sand. the ball valves don't last long
Ken

Ken, a picture would be great. I know i have a heap of others too, but the more piccies the better i figure.
Have you found the 3.2mm nozzle is big enough? thats my main concern. I don't want to spend days blasting getting the paint and rust off. I have a fair amount of air available, so i should be able to use a fair sized nozzle.

 

[perry]

Ken, a picture would be great. I know i have a heap of others too, but the more piccies the better i figure.
Have you found the 3.2mm nozzle is big enough? thats my main concern. I don't want to spend days blasting getting the paint and rust off. I have a fair amount of air available, so i should be able to use a fair sized nozzle.

Good Job and thanks for the detailed pics Tazza, If you've never used 'black dimond' blasting media I recommend it, about $7.50 for 50lbs at Northern tool, it's thicker and cuts faster.
Is your drive the same as a 853?.

 

[Tazza]

Good Job and thanks for the detailed pics Tazza, If you've never used 'black dimond' blasting media I recommend it, about $7.50 for 50lbs at Northern tool, it's thicker and cuts faster.
Is your drive the same as a 853?.

Perry - shipping from the USA to Australia would kill me but when i start building the blaster i sure am going to start looking for options. I know i can't use beach sand, i use ilmenite (spelling) in my hand held blaster that works well, not sure on the price these days.
I honestly don't know if my drive is the same as an 853, but i would suspect it would be very close, just larger parts. I did read the other thread and threw in my 2c worth. I did point out anything can be fixed, just depends how patient you are... A good example is my 743..... It took a lot of time, but in the end it was totally worth it.
As for the blaster, my dad has found an old LPG tank from a forklift and also one for a house. I believe the one for a house will be a tad large, when full of sand no one will be able to move it! Even the smaller one i believe will weigh a bit.
Ken - can you provide a picture of the nozzle? i hoped to make one out of carbon steel and heat treat it, even if it didn't last long i'm sure it would get the job done. I still don't know how it is done inside, i sort of have an image of a cone shape in my head that makes it speed up as it gets to the tip. The hand held one i have simply has a nozzle about 4" long with a small countersunk hole at the base.

 

[skidsteer.ca]

Perry - shipping from the USA to Australia would kill me but when i start building the blaster i sure am going to start looking for options. I know i can't use beach sand, i use ilmenite (spelling) in my hand held blaster that works well, not sure on the price these days.
I honestly don't know if my drive is the same as an 853, but i would suspect it would be very close, just larger parts. I did read the other thread and threw in my 2c worth. I did point out anything can be fixed, just depends how patient you are... A good example is my 743..... It took a lot of time, but in the end it was totally worth it.
As for the blaster, my dad has found an old LPG tank from a forklift and also one for a house. I believe the one for a house will be a tad large, when full of sand no one will be able to move it! Even the smaller one i believe will weigh a bit.
Ken - can you provide a picture of the nozzle? i hoped to make one out of carbon steel and heat treat it, even if it didn't last long i'm sure it would get the job done. I still don't know how it is done inside, i sort of have an image of a cone shape in my head that makes it speed up as it gets to the tip. The hand held one i have simply has a nozzle about 4" long with a small countersunk hole at the base.

Tazza yes I'll get on that.
But you want a ceramic insert. Mine used the tiny ones and they are available for about $1 each. You would be best off to buy a nozzle or make yous to fit a common ceramic tip, it has to have something that can be changed out easily when the bore wears oversized.
Here is a link to it
http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=34202
I'll get those pics
Ken