case 780 impulse buy, so many questions....

[NMBlackBetty]

My dad rebuilt a 336BD in his 680E I think 4 times, I have replaced a liner and piston in one when it dropped a valve in the gravel pit (that was a fun time). I have also rebuilt a 504BDT in a 2670 tractor. All I know is the counterbores (the bottom ledge in the block where the liner seals into) are prone to cracking, and are usually all corroded and pitted to chit. Those injectors probably don't have a prayer of coming out, and every single exhaust manifold bolt is going to break off but who cares, you'll want to put new heads on anyway (or have yours rebuilt, in any case you won't care). Be extra careful and folllw book procedure for torque when installing the water jacket and intake manifold, they are lighter aluminum and you can break the mounting holes out. Pretty simple engines, no balance shafts to deal with like newer 4 bangers.

Wow! So much good information, thank you for taking the time to share it!

 

[NMBlackBetty]

The engine oil pump has four mounting bolts.
There are shims between the pump and block that sets the crankshaft gear and pump gear clearance. The gears have timing marks on them.
it is critical to time it correctly because it controls the crankshaft vibration.
Those shims can sometimes stick to either the pump or block. Sometimes both when the pump is removed.

Just to make sure I am understanding correctly then....

When I take it off, count the shims and photograph the timing. Replace the shims with the same number and size of shims, and exact same bolts and make sure the timing is exactly the same when I reassemble the engine? Or am I way off base?

 

[NMBlackBetty]

I'm wondering what 25 years of sitting has done to the machine. There is a good chance 50% of the hydraulic hoses will need replaced once it runs. Greater chance the hydraulic cylinder seals are rotted.

Do you have much experience in these types of repairs, including the engine? Tooling?

I've restored dozens of old diesel trucks, from 1 ton pickups to a few stewart and stevenson military trucks, a dump truck conversion and an old semi. Never a piece of construction equipment though.

I'm approaching this the same as I have with the old trucks. Even if I think I know something, I assume I don't know it and verify the info before I proceed with every step. If I can find a new part for something, I replace it, right down to the lug nuts, although in this case I need to find 2 new front rims as well as these are dinged up and bent. I won't be repacking the hydraulic cylinders, I'll be looking to buy new ones. And even if it looks fine, I will be replacing every hydraulic line. New seat, glass, pretty much everything. I've seen rebuilt engines for sale around $7,000 but even though it's likely to be more expensive, want the experience of rebuilding this one just to gain the knowledge. I plan on stripping it down to a bare block, sending it off to be machined and powder coated, the rebuilding it myself with as many new parts as I can find. I like to tinker, and like to be wrong so I can learn from it. I'm almost disappointed when I rebuild an old diesel engine and it fires up perfectly the first time as I feel like there is nothing more to learn from it.

I usually send out or replace parts that need to be machined, I have a lathe and welder but that's where my machines end. We have a large sand blaster and paint booth, but that's for cosmetic work if I get it to live again.

All in all, this started out as a $500 impulse buy and in my mind, I saved it from being torched to pieces and hauled off to the scrap yard. If I fail at my engine rebuild, I'll suck it up and buy a reman engine. Same with the Trans. But I don't give up easy.

 

[NMBlackBetty]

Looking at these pictures, it doesn't look half bad. Get the engine running, then do hoses and cylinders as they go. Might avoid eating all this at once.

Thanks JL. I though she was kind of pretty. I look at it more as a hobby. I don't even need the machine, 2 of our tractors have backhoes on them and we have a new 85p excavator. It's not "eating" expenses for me, it's making something old new again and learning from the experience.

 

[NMBlackBetty]

I'll be the voice of reason.
Parts will probably be difficult the case/new holland parts system is falling apart I've had trouble getting stuff
If you truly intend to do a nut and bolt resto it is going to be about 4 times more expensive then you intend.
When all Said and done you will still have a old over weight backhoe

You're probably right, I haven't even set a budget for the project, I seldom do.

Talking to my local case dealer, I can already see parts will be a fun journey.

Thank you for letting me know you're having issues though, it helps me set reasonable expectations.

 

[Tyler d4c]

You're probably right, I haven't even set a budget for the project, I seldom do.

Talking to my local case dealer, I can already see parts will be a fun journey.

Thank you for letting me know you're having issues though, it helps me set reasonable expectations.

I by no means am trying to stop you but expect some bumps in the road and keep us posted if you do go for the rebuild

 

[NMBlackBetty]

I by no means am trying to stop you but expect some bumps in the road and keep us posted if you do go for the rebuild

I'm bull headed, or so my wife says. I don't think anything is going to stop me, although not having a serial number sure is holding me back a lot.

 

[Tinkerer]

Can you get the serial number that is/ should be on the differential ?
That will indicate what model the tractor is and which parts book you need to use.
Provided it has the original or same as, differential in it.
I am pretty sure you have an early model 780CK.

check this brochure out >https://assets.cnhindustrial.com/ca...es/cce_LB_Historic_780_specs_06-26-2009_1.pdf

 

[NMBlackBetty]

Can you get the serial number that is/ should be on the differential ?
That will indicate what model the tractor is and which parts book you need to use.
Provided it has the original or same as, differential in it.
I am pretty sure you have an early model 780CK.

check this brochure out >https://assets.cnhindustrial.com/ca...es/cce_LB_Historic_780_specs_06-26-2009_1.pdf

i don't remember seeing one on it, I was going to go up to the machine today to look more, but it has poured rain all morning and our ranch road is a mud pit. May be Saturday before I can get out of here to go look again.

The Sims cab tag says it's just a 780, where the stickers were on the side (they have been painted over) it just says 780, no numbers I have found give me anything, but I did chat with a guy who used to work for the forest service division that use to own it back in the '70s and he said if he remembers correctly it was a 1972 780 CK, he was in his 20's back then and worked in the shop and vaguely remembers working on it, they had been requesting a backhoe for their district for years I guess and it was a big deal when they finally got it. At the forest service office, there is a photo of the machine in 1974 digging out a bunch of brush that dammed up an arroyo and flooded miles of land in the district so I know its at least 1974 or older, it still has the same forest service sticker on it in the same place, just painted over now, so I know its the same machine.

I will report back Saturday night after I go out again with a fine tooth comb to try and find something to identify the machine. I cant tell you how much i appreciate your help with places to look.

 

[Coy Lancaster]

Hey NBLACKBETTY That's a good looking machine. There is a lot of work ahead of you for sure. One thing I can help you with is there should be a serial number on the machine stamped on the frame under the radiator support. If you remove the grill and look on the left side frame.

 

[chestypuller]

that 780ck service manual still floating around i got emailed one now i cant find it, help

 

[NMBlackBetty]

Going to look for the serial number again today, thank you all for your suggestions on other places to look. Got a quick question though. I need some new front lug nuts to get it moved. Any idea where to find some? I checked broken tractor already and they have nothing listed for the 780.

 

[Tyler d4c]

Should be able to source off size and thread pitch there probably 1/2 fine thread

 

[JaredV]

Any tractor parts place should have or be able to get them. Looking forward to seeing your progress.

 

[Tinkerer]

The CNH dealer near me has a huge assortment of lug bolts and nuts on his shelves.
If you can't find that particular bolt, a stud and nut can be used in its place

 

[Delmer]

most of that sort of stuff is going to be standard ag stuff, you could probably borrow off a junk tractor if you wanted to. 9/16 NF probably, don't remember what the thread count is but it's standard.

Since you're looking to replace stuff rather than rebuild, it's a good thing you got a case. A 580 would have made your job a whole lot easier, 780's are a little more rare, aren't they? I know if you were doing a Deere or Cat, a lot more stuff would be NLA, and you wouldn't want to pay the price even if they had it. Case has far more aftermarket support. Not that I would suggest your project.

The cab won't be any help that I've seen, the cab tags will be a generic certification for the models they fit, not an ID.

 

[edgephoto]

I know if you were doing a Deere or Cat, a lot more stuff would be NLA, and you wouldn't want to pay the price even if they had it. Case has far more aftermarket support. Not that I would suggest your project.

The cab won't be any help that I've seen, the cab tags will be a generic certification for the models they fit, not an ID.

@Delmer Interesting you commented on parts for CAT to be hard to get. I have a CAT 426 that I have been fixing. I have not really found parts to be an issue. About the only thing this is discontinued is ROPS frame parts. I even commented to the CAT dealer how I was surprised at how easy it was to get parts.

 

[Tyler d4c]

@Delmer Interesting you commented on parts for CAT to be hard to get. I have a CAT 426 that I have been fixing. I have not really found parts to be an issue. About the only thing this is discontinued is ROPS frame parts. I even commented to the CAT dealer how I was surprised at how easy it was to get parts.

All I can say I have had way better times getting both deere and cat parts then case/new holland by a whole lot.

 

[Tinkerer]

Just to make sure I am understanding correctly then....

When I take it off, count the shims and photograph the timing. Replace the shims with the same number and size of shims, and exact same bolts and make sure the timing is exactly the same when I reassemble the engine? Or am I way off base?

No you are not “way off base”.
You are 100% correct.
Take photos of the connecting rods on the crankshaft so you don’t put them on wrong on reassembly. I like to stamp an arrow on the rod caps
Same is true with the pistons if you replace them. Especially that they are not put on the con rods backwards.

 

[Delmer]

It wouldn't be the first time I'm wrong. I'll stand by there's more aftermarket stuff for Case, and a 580 will have better parts support than a 780.

I haven't been impressed with older JD BACKHOE parts availability. Really don't know Cat or Case enough to compare though, just going by what I read on here.