1981 Bobcat 743 Rebuild

Dameon · Apr 22, 2014

I bought a "lightly" (2300 hours) used 743 (serial 5019-M-12xxx) at an equipment auction mainly for use around the house. Based on loose web research, it seems to be a 1981 vintage and I've been assuming it is a Kubota engine (based on looks and color), but I think the serial indicates a Mitsubishi, hence the "M"? The manual seems to indicate that only a Kubota went in the 743, while the 742 got the Mitsubishi. Until I pull it out, I won't know for sure I guess. It came with one accessory (backhoe), so I'm hoping to locate a front loader for a good price. I have a pallet fork setup from a forklift I plan to fab up as a bobtach accessory. Maybe a auger some day.

Dameon · Apr 22, 2014

Anyway, the plan is to strip it down as much as possible (without getting too anal) and sandblasting/repainting everything. Sticker kits are available on eBay for a reasonable price. I'll probably get a portable media blasting setup from Harbor Freight, something like this: http://www.harborfreight.com/110-lb-pressurized-abrasive-blaster-60696.html would probably work. I don't need to take the whole thing down to metal, just remove a layer of grime and rough the paint to get good adhesion on my repaint. Any suggestions on blasting media? Sand, Aluminum Oxide, Walnut shell, glass? What about paint and method? I was going to use the highest grade of rattle can I can get. Something with a rock hard finish and high durability. Is that asking too much from a rattle can? Should I consider wheeling the chassis down to the local autobody shop and having them hit it a couple coats of auto paint?

Dameon · Apr 22, 2014

Dameon said:
Anyway, the plan is to strip it down as much as possible (without getting too anal) and sandblasting/repainting everything. Sticker kits are available on eBay for a reasonable price. I'll probably get a portable media blasting setup from Harbor Freight, something like this: http://www.harborfreight.com/110-lb-pressurized-abrasive-blaster-60696.html would probably work. I don't need to take the whole thing down to metal, just remove a layer of grime and rough the paint to get good adhesion on my repaint. Any suggestions on blasting media? Sand, Aluminum Oxide, Walnut shell, glass? What about paint and method? I was going to use the highest grade of rattle can I can get. Something with a rock hard finish and high durability. Is that asking too much from a rattle can? Should I consider wheeling the chassis down to the local autobody shop and having them hit it a couple coats of auto paint?

I'm going by the Bobcat place in the morning to pickup a full set of filters (air, oil, hydraulic). Probably use Rotella oil for both engine and hydraulic. Manual suggests 10w-30 or 10w-40 for hydraulic. I'll probably use 10w-40 for both (engine and hydraulic). Manual says 9 quarts for the engine and 6 gallons for the hydraulics. This model seems to indicate a chaincase and I'm sure its probably never been replaced. That's another 32 quarts. I assume 10w-40 will work there as well.

Dameon · Apr 22, 2014

Dameon said:
I'm going by the Bobcat place in the morning to pickup a full set of filters (air, oil, hydraulic). Probably use Rotella oil for both engine and hydraulic. Manual suggests 10w-30 or 10w-40 for hydraulic. I'll probably use 10w-40 for both (engine and hydraulic). Manual says 9 quarts for the engine and 6 gallons for the hydraulics. This model seems to indicate a chaincase and I'm sure its probably never been replaced. That's another 32 quarts. I assume 10w-40 will work there as well.

First effort is to get it running smoother. It started with great effort then died almost right away. When I went around to pour some fresh fuel in I noticed it had no gas cap. Good chance the tank (and now the injection system) is full of water. So now I have to find a gas tank drain (or removal) method and sort that out. Manual shows how to bleed the fuel system, but not remove the tank.

Dameon · Apr 22, 2014

Dameon said:
First effort is to get it running smoother. It started with great effort then died almost right away. When I went around to pour some fresh fuel in I noticed it had no gas cap. Good chance the tank (and now the injection system) is full of water. So now I have to find a gas tank drain (or removal) method and sort that out. Manual shows how to bleed the fuel system, but not remove the tank.

I posted in several "sections" so responders could reply easier to a specific thought. This forum software is extremely basic and very limited on formatting. Even something as simple as a paragraph break seems impossible. I'll get some before pictures on this thread soon and try to update as I go along. Thanks.

antfarmer2 · Apr 22, 2014

Dameon said:
I posted in several "sections" so responders could reply easier to a specific thought. This forum software is extremely basic and very limited on formatting. Even something as simple as a paragraph break seems impossible. I'll get some before pictures on this thread soon and try to update as I go along. Thanks.

Email me at antfarmer1212at yahoo.com and I will talk to you on the phone if you would like you have a lot going on and will get you through it if your in the U.S. let's hold off on the paint job lol

antfarmer2 · Apr 22, 2014

antfarmer2 said:
Email me at antfarmer1212at yahoo.com and I will talk to you on the phone if you would like you have a lot going on and will get you through it if your in the U.S. let's hold off on the paint job lol

It is 1702 kubota 36 hp unless changed I use 15-40 in both and chaine case

Dameon · Apr 22, 2014

antfarmer2 said:
Email me at antfarmer1212at yahoo.com and I will talk to you on the phone if you would like you have a lot going on and will get you through it if your in the U.S. let's hold off on the paint job lol

Thanks for the generous offer. As soon as I get a break in my day, I'll contact you and we'll have a chat.

antfarmer2 · Apr 22, 2014

Dameon said:
Thanks for the generous offer. As soon as I get a break in my day, I'll contact you and we'll have a chat.

No prob I have been where you are don't think my one typing finger can give you all the info you will need lol

Dameon · Apr 22, 2014

antfarmer2 said:
No prob I have been where you are don't think my one typing finger can give you all the info you will need lol

antfarmer2 on 04-22-2014 12:32 PM: "It is 1702 kubota 36 hp unless changed I use 15-40 in both and chaine case" With only 2300+ hours, it seems unlikely the engine was changed, so I'd tend to agree with you. I also have a Kubota BX tractor and the general engine shape and color looks the same, hence my assumption. Since I'm in a warm climate area, heavier oil is always a good idea. If I can find Rotella in 15w-40, I'll go with that. Thanks again.

antfarmer2 · Apr 22, 2014

Dameon said:
antfarmer2 on 04-22-2014 12:32 PM: "It is 1702 kubota 36 hp unless changed I use 15-40 in both and chaine case" With only 2300+ hours, it seems unlikely the engine was changed, so I'd tend to agree with you. I also have a Kubota BX tractor and the general engine shape and color looks the same, hence my assumption. Since I'm in a warm climate area, heavier oil is always a good idea. If I can find Rotella in 15w-40, I'll go with that. Thanks again.

What state are you in also there is a hidden brass filter that some of the older ones have they can tell by the s# so make sure you have it with you when you get the filter kit

Dameon · Apr 22, 2014

Dameon said:
antfarmer2 on 04-22-2014 12:32 PM: "It is 1702 kubota 36 hp unless changed I use 15-40 in both and chaine case" With only 2300+ hours, it seems unlikely the engine was changed, so I'd tend to agree with you. I also have a Kubota BX tractor and the general engine shape and color looks the same, hence my assumption. Since I'm in a warm climate area, heavier oil is always a good idea. If I can find Rotella in 15w-40, I'll go with that. Thanks again.

The paint job is the last step. I'm not going to waste time and money painting a unit that isn't a feasible candidate for a rebuild. Idea gathering right now. Priority right now is fluids.

Dameon · Apr 22, 2014

Dameon said:
The paint job is the last step. I'm not going to waste time and money painting a unit that isn't a feasible candidate for a rebuild. Idea gathering right now. Priority right now is fluids.

I am in Louisiana. The brass filter (I assume) is part number 6563995 which is listed as Hydraulic Filter (Bronze In-Line). But the parts guy at the Bobcat dealer here said he'd have to order that if I wanted it. He had all other filters in stock... 6598362: Air Filter (Inner), 6598492: Air Filter (Outer), 6675517: Oil Filter, 3885315: Fuel Filter (In-Line), 6515541: Hydraulic Filter (10 micron).

antfarmer2 · Apr 22, 2014

Dameon said:
I am in Louisiana. The brass filter (I assume) is part number 6563995 which is listed as Hydraulic Filter (Bronze In-Line). But the parts guy at the Bobcat dealer here said he'd have to order that if I wanted it. He had all other filters in stock... 6598362: Air Filter (Inner), 6598492: Air Filter (Outer), 6675517: Oil Filter, 3885315: Fuel Filter (In-Line), 6515541: Hydraulic Filter (10 micron).

Don't order it you may not need it and I have one they said I needed it but did not I am in Texas

antfarmer2 · Apr 22, 2014

antfarmer2 said:
Don't order it you may not need it and I have one they said I needed it but did not I am in Texas

My fuel filter is a can on the right side if you have that be careful the bottom is glass

antfarmer2 · Apr 22, 2014

antfarmer2 said:
My fuel filter is a can on the right side if you have that be careful the bottom is glass

First thing is the fuel cap to pull the tank take the four nuts off the cage undo the two plugs on the left side of seat when sitting if it has them lift up cage and tie it back there is a strap holding the hydro and fuel tank get a new pick up tube and screen now it will bite you in the ass later and replace all lines

Dameon · Apr 22, 2014

antfarmer2 said:
First thing is the fuel cap to pull the tank take the four nuts off the cage undo the two plugs on the left side of seat when sitting if it has them lift up cage and tie it back there is a strap holding the hydro and fuel tank get a new pick up tube and screen now it will bite you in the ass later and replace all lines

Thanks for that tip! That's the kind of stuff I really look for... been there, done that, experience. Pickup tube and screen added to shopping list.

antfarmer2 · Apr 22, 2014

Dameon said:
Thanks for that tip! That's the kind of stuff I really look for... been there, done that, experience. Pickup tube and screen added to shopping list.

Let's get the engine first there are some checks you want to make before draining hydr fluid and while the cab is up need to grease and check the ujoints very important and a pita

antfarmer2 · Apr 22, 2014

antfarmer2 said:
Let's get the engine first there are some checks you want to make before draining hydr fluid and while the cab is up need to grease and check the ujoints very important and a pita

Once you get the cab up look to the left side of the hydro pump standing in front of the cat if there is one big hose going to the left you don't have the brass filter if there is a big steel block to the left with three hoses comming off the block you do need the filter

1981 Bobcat 743 Rebuild

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