For 750 TLB, just bought one, questions

750owner

Member
Hi, a newbie here.

I just bought a fixer-upper Ford 750 TLB, and had a few questions.

It's a 197? turbocharged 4 cylinder diesel. I read somewhere here that it probably has a a 256 CID, but I can't for the life of me figure out what the spec's are on both the engine and the machine. The engine is painted blue underneath, so it probably was already replaced from another Ford ag tractor.

Questions:

1) Where can I find a service and operator manual for the 750 tlb? Searching the web, all that seems to come up is the 750 backhoe attachment, at least from the looks of the drawing on the covers of the reprints out there. One site suggested it's the same as the 6500 tlb.

2) Where's the SN or VIN on these things? The engine has some sort of SN on the right side bottom, but as I said, it's probably not the original.

3) What engine do these things have? What's the designation?

4) If anyone wants to venture a guess on what happened to it... The guy I bought it from took deliver and had it running for an hour. Apparently, rather suddenly it started belching white smoke and then oil squirted out of the turbo. The turbo is zorched (the impeller rattles around in it). The engine appears to be somewhat frozen, meaning it won't crank over but the flywheel twitches. That's a little odd to me if one or more pistons are frozen, unless the bearings are fried too (enough so the crankshaft can wiggle). It's been sitting for 2-3 yeas after that incident. I'm trying to piece together a scenario that makes sense. The turbo I can deal with, but I'm hoping I don't need to do a complete engine rebuild or replacement. Certainly white smoke could indicate antifreeze in the exhaust, so the head gasket might have blown and hence water in the cylinders for some time might be the cause of the freeze. But why would the turbo have gone out too? Unless water also got in the oil and ultimately into the turbo's bearings or such while it was running...

Thanks!
 
your engine may be hydro locked from the turbo leaking engine oil into the intake manifold.
are you trying to turn the engine over with the starter? have you tried to rotate the engine backwards? (counterclockwise) you could pull the injection nozzles and then try to turn the engine over as well.
 
Model number and serial number should be in two spots. One is on a foil sticker on the under side of the right hood panel, above the battery, and the other location is on a flat spot on the transmission bell housing just rearward from the starter.

The 750 TLB was only made from 1975-1977 before it was replaced by the 755. The engine should be basically the same as the 7600/7700 ag and row crop tractors and the 755 TLB.
 
Okay, I located the model number and the "Unit" (thanks Sean in PA). The placard is fairly scratched up but I found the stampings on the transmission bell housing as well (though not the serial number--maybe need to look some more). Piecing together between the two:

Tractor Number: ?5?32?? could be C5?3210
Model: FF211S
Unit: 8H15B
Engine: 8E23B
Transmission: 8F29B
Rear Axle: 8F14? could be 8F140
Hyd Pump: ***
Hyd Lift: ***

I downloaded the JenSales reproduced operator's manual for the 750, but I can't find a service manual for the 750 (though the 755B has one--about 450 pages ~$150). Anyone know if such a manual exists?

tego, I must say I _really hoped_ the oil hydrolocking theory was it, but alas... not.

As they say, "Here's yer problem!"

After sponging out:
mvphoto13341.jpg



Inspecting the head gasket, I didn't see any signs of it being blown and if so that would probably have meant water in one or two cylinders I would think. They were all wet however.

Clearly there was a "event" which introduced water into the cylinders some other way, which could well have been through the turbo, for instance by way of the turbo's bearings which are shot. As I mentioned, the engine suddenly blew lots of smoke and then the turbo apparently puked out a lot of oil and the previous owner shut it down. Where would the water have come from? I'd think if it threw a rod the result would have been more dramatic. I suppose I need to pull the oil pan off and see what's up on the underside.

Anyway, _IF_ the block isn't damaged by say a thrown rod, is this reasonably rebuildable where she sits? The plan right now is to clean up the crud in the cylinders as best as possible, cut a block of wood to fit into them, and beat on each piston with a sledge in hopes of freeing them up. Before I left her this afternoon I soaked each piston with PB Blaster and topped off with a 1/4" of diesel fuel for a good soaking until next week at least. I could throw some flame at it to heat things up with a propane burner--I would think that might help?

If I can free them up, what next? I figure at least I'd drop a hone down each cylinder to clean it up a bit better. I see rebuild kits are about $400-$500. That's probably a better option in the long run, but right now I just want it to run. The big guess is whether it will run at all since i don't know what the root cause of all this was. (e.g. thrown rod, etc).

I also found some rebuilt complete engines for about $4000+ and a rebuild block with pistons/cam/etc but no head or oil pan, etc. for about $2000. How easy is it to drop/lift the engine in these things? It looks like it unbolts pretty easily, but there seems to be some pivoting/mounting pins near the front which I can't figure out.

With the rebuild kits, there appear to be some variables in the piston diameters which need to be spec'd. Any advice on that?

Thanks again.
 
FF211S is a 750 with a diesel engine and 3x3 torque converter auto reversing transmission.

Unit# 8H15B means it left the assembly line on August 15, 1978 during the day shift. I know that I said above that the 750 was only made from 1975-1977, but that was what the parts site shows. I have other references that show that the 550, 650 and 750 were made at least partway through 1978 before the 555, 655 and 755 replaced them.

The engine, transmission and rear axle numbers are all 1978 numbers as well.

Sorry I can't help much with your questions on the the stuck engine

You might try a New Holland Dealer to see if they can get you a service manual or if they could tell you what other models were included in the same service manual so you can look for one of those. The parts books that I can find on line for the 750 also include the 6500 and 7500, and so I would assume that the 750 has enough in common with them that the service manual for those models would have most things on the 750 covered.
 
Hi All, thanks for all the help so far. The saga continues.

I did an in frame honing job, bought a new turbo, and finally got the engine running again. Whew! However, when I really load it up, I'm getting a little stream out of the radiator cap... concerns me. I hope I'm not getting a little leak in the head gasket... Maybe will torque it up some more? Thoughts on that appreciated.

I am rebuilding steering rams since one leaks like a sieve, plus new tie rod ends. Also, while fussing with steering once she was running, I refilled the pump several times (prob 1/2 gal+), and quickly the steering hydraulic fluid foamed up a little and turned somewhat beige. Is that a sign of water in there? Geesh! There's water everywhere in this thing!!! Beats me how it would get in there.

Primary hydraulics seem in good shape.

The machine moved, but not well.

Key questions:

1) On the steering, once the cylinders were refilled, it turned to the left okay but was very hesitant to turn to the right. With higher RPMs it did better. Is this just a matter of leaky cylinders, or does it indicate a problem with the steering valve unit? I ordered new seal kits for the pump and cylinders, but not the steering unit, yet at least. (BTW I still need to road the machine a couple miles to my shop area, it's still in the field. Figured I can steer "enough" for now.)

2) Transmission/Brake: The tranny fluid levels seem okay, not burnt, and filled. However, I had a real hard time getting the machine to move. Could this possibly be a stuck hand brake? It would move fwd/reverse about the same in 1st gear with full power, but comes to a quick stop. i.e. it doesn't seem to roll. It won't move in 2nd or 3rd, either direction. The foot brake pedals and linkages all move in and out of the casings and look okay. I haven't been able to debug the hand brake though.

-or-

Is this a transmission problem? I discovered there is a lever on the steering column which is apparently the "dump valve". What is does that do? I saw a reference somewhere indicating that it could be related. I couldn't find a decent reference to it in the operator manual though, or online. It has a locking position on it as well. Upon quick inspection at least, I couldn't find what linkages on the transmission it's supposed to actuate. However, I also found a lever going into the side of the tranny which didn't seem to be actuated by anything. It's spring loaded, right above one of the foot brake linkage points just in front of the axle on the left side. Could there be a linkage broken somewhere?



I think I located an aftermarket print copy of the service manual, ~400 pages, $150ish. Does anyone have a spare copy or digital version?

Thanks again! Everyone says this is a heck of a machine once it runs.
 
(reply to post at 06:41:01 11/25/14)

The parts books that I can find on line for the 750 also include the 6500 and 7500, and so I would assume that the 750 has enough in common with them that the service manual for those models would have most things on the 750 covered.

Hi Sean, thanks. Any idea what the difference between the 750 and the 7500 is? I can find repair manuals for both the 755 and 7500, but not the 750 strangely enough. Manuals on ebay seem to run about $120 and up, hate to get the wrong one.
 
(quoted from post at 22:27:58 03/08/15)
Hi Sean, thanks. Any idea what the difference between the 750 and the 7500 is? I can find repair manuals for both the 755 and 7500, but not the 750 strangely enough. Manuals on ebay seem to run about $120 and up, hate to get the wrong one.

7500, 750 & 755 are all industrial models with the same basic engine and chassis design, just made at different times. The 7500 was the earliest, made from 1973-1975. The 750 replaced the 7500 and was made from 1975-1978, and the 755 replaced the 750 and was made from 1978-1983. They all had the 256 turbo engine except in 1981 they upped it in the 755 to the 268 turbo and added "Blue Power Special" to the name. A New Holland dealer should be able to get you a service manual specifically for the 750, but it will likely be more expensive than the ones on ebay.
 
Poking around, I found approximately this:

550 1975-1977 3 cyl
555 1978-1982 3 cyl
555a 1983-1984 3 cyl
555b 1986-1988 3 cyl
555c 1989-1992 3 cyl
555d 1992-1995 4 cyl
555e 1996-2000 ? cyl

6500 74-?? 4 cyl (skip loader, i.e. no backhoe)

655A 85-?? 4 cyl

7500 73-75 4 cyl 256/4.2L
750 75-78 4 cyl 256/4.2l
755 78-83 4 cyl 256/4.2l (later 4.4l?)
755A 84-?? 4 cyl 4.4l?
755B ?? 4 cyl 4.4l?



I managed to find a manual for a 755B, which so far appears to be pretty similar to the 750.
 
The good news, now that I have a manual, is that it looks like the cable that actuates the hand brake lever on the transmission case is inoperative, and I presume the brake is thus "set". Fingers crossed that repairing this will solve most of the moving problem.
 
Hi All,

Well, the saga continues.

After unfreezing the engine, honing, new rings and bearings, new turbo, reassembly, all in frame in the woods, brake freed up, and various other tweaks to get the machine to move, I managed to road it to my location about an hour away, and to my horror discovered that the original problem (water in the oil, oil gunk up, turbo bearings fry) reoccurred.

I pulled the head this morning, _fortunately_ without draining the radiator, and after drying everything out, discovered that the #1 cylinder was filling ever so slightly with coolant water. After looking closely, I found the problem:

[b:49ed0b1350] A pinhole leak about half way up the cylinder wall![/b:49ed0b1350]

Ughhhh! What's happening is the water leaks into the chamber on the upstroke, and into the crankshaft casing on the down-stroke, hence the water in the oil. We're talking about a couple gallons or three consumed during that trip. What should have tipped me off was the steam coming out of the valve cover vent pipe.

I would have never found the leak had I emptied the block of coolant before pulling the head, so that's good I suppose....

The new questions:

1) Can the block be "patched" or sealed? It would obviously be way easier to put in some sort of coolant-based sealant product, or hit the hole for second with the welder and clean up the bore, than to pull the block. I'm guessing "no" on these because of the pressure (for the sealant), and it's hard to weld to castings I'm told (and I'm guessing probably it would crack later due to hardness differences and hence uneven expansion).

2) If block can't be fixed per 1), I suppose it could be sleeved, or I can get a replacement block. Has anyone ever sleeved a block, in the field, in-frame?

3) Presuming I need to pull the engine, can it be done without splitting the tractor? The machine is still in the field, so heavy lifting equipment is not readily accessible. Basically it's going to be 4x4's and a chainfall.

4) If I opt to sleeve #1, do I really need to do them all? The engine runs fine otherwise.

5) The turbo bearings are shot, but it looks like the impeller is okay. The housing walls are just barely scratched. Can these be rebuilt? Details if so? Is it a DIY job?

Thanks again in advance.
 
Looking around some more, I found at least the concept of "pinning" the leak, which is to say finding the right sort of pin to insert firmly into the hole. Does anyone have any ideas on this?

One option may be some sort of pliable "tack" that could just be pounded in.

Another option would be to drill out and tap the hole, put in a screw

Bore cleaned up after of course.
 
Here's a great article on "cavitation", the apparent cause of the problem.

http://www.oilburners.net/articles/cavitationartic.html

In short, the flexing of the cylinder as it fires causes the water jacket to expand and contract very fast. When it contracts after the explosion, it causes a vacuum in the coolant.
Apparently this leads to corrosion and development of these sort of pinholes, especially if there are little pockets in the casting (which is not uncommon). Apparently using certain coolant additives prevents this sort of corrosion, and diesels are particularly prone to it due to the high compression (and a turbo to boot).

I found various references to sleeving:

- just the leaking cylinder (cheaper, but fine)
- all of them (more reliable, since if one is gone, the others may be close behind)
- that it can't be done (since the cylinder is already corroded away from the coolant side, so boring it out just makes the wall that much thinner).

Please comment.

Thanks!
 
Here's a great article on "cavitation", the apparent cause of the problem.

http://www.oilburners.net/articles/cavitationartic.html

In short, the flexing of the cylinder as it fires causes the water jacket to expand and contract very fast. When it contracts after the explosion, it causes a vacuum in the coolant.
Apparently this leads to corrosion and development of these sort of pinholes, especially if there are little pockets in the casting (which is not uncommon). Apparently using certain coolant additives prevents this sort of corrosion, and diesels are particularly prone to it due to the high compression (and a turbo to boot).

I found various references to sleeving:

- just the leaking cylinder (cheaper, but fine)
- all of them (more reliable, since if one is gone, the others may be close behind)
- that it can't be done (since the cylinder is already corroded away from the coolant side, so boring it out just makes the wall that much thinner).

Please comment.

Thanks!
 
Here's a great article on "cavitation", the apparent cause of the problem.

http://www.oilburners.net/articles/cavitationartic.html

In short, the flexing of the cylinder as it fires causes the water jacket to expand and contract very fast. When it contracts after the explosion, it causes a vacuum in the coolant.
Apparently this leads to corrosion and development of these sort of pinholes, especially if there are little pockets in the casting (which is not uncommon). Apparently using certain coolant additives prevents this sort of corrosion, and diesels are particularly prone to it due to the high compression (and a turbo to boot).

I found various references to sleeving:

- just the leaking cylinder (cheaper, but fine)
- all of them (more reliable, since if one is gone, the others may be close behind)
- that it can't be done (since the cylinder is already corroded away from the coolant side, so boring it out just makes the wall that much thinner).

Please comment.

Thanks!
 
Posting an update for archival purposes.

This cavitation issue turns out is quite real, particularly--apparently--in these Ford 256 turbo diesel's.

I made an attempt to seal the pinhole with a ceramic-type block sealer coolant additive, first flushing the block thoroughly with water and a coolant flush additive (by the same manufacturer). The point of the flushing is that the sealer does not work if there's any antifreeze present, and also the flushing additive removes some rust for a better seal. After flushing, one add the sealant and runs it for an hour or two, drain, and let cure for 12+ hours.

It seemed like it worked, and in fact I did a couple days of digging with the machine.

But, alas... upon returning to my base camp I found the coolant level way low, and of course it ended up in the oil pan again (i.e. I drained out a gallon or more when I cracked open the oil drain plug).

So....

It looks like I need to sleeve the thing.

I found a shop in the region that quoted me about $600-$700 to do that, including magnafluxing and new crankshaft bearings and seals. Seems reasonable, though I don't know yet if that includes the sleeves.

The hard part now is pulling the engine since I'm not in a shop. Having a backhoe would be nice... how ironic. The good news is that the service manual says one can pull the engine on these without cracking the tractor in half. I'll have to rig up some sort of gantry with a chainfall, or see if I can get some other machine to swing by for a bit.

Any additional advice appreciated.

Thanks
 
Just curious how the 750 "saga" is going. I've got a 755 and just noticed this thread a few weeks ago. Doing all that work "in the field" is impressive. I was in the same situation and did injector pump work, replaced the radiator, hose replacement, etc. "in a field" and it was not real easy. (i.e. not having ready access to tools, a good vise or machinery).
 
(quoted from post at 06:11:37 09/16/15) Just curious how the 750 "saga" is going. I've got a 755 and just noticed this thread a few weeks ago. Doing all that work "in the field" is impressive. I was in the same situation and did injector pump work, replaced the radiator, hose replacement, etc. "in a field" and it was not real easy. (i.e. not having ready access to tools, a good vise or machinery).

Not a lot of updates at present. The machine runs fine as long as I drain the water out of the oil pan before starting it, and refilling the radiator.

I did just acquire a heavy equipment engine hoist from craigslist for cheap which will yank the engine out no problem, but I didn't get to doing it yet, and I found a rebuilt turbo for $300. I also need to rebuild the steering valves and after sleeving, it'll be a decent enough machine. I don't know if I want to dive into the tranny while the engine is out. It needs new brake pads too.
 
It needs new brake pads too.

That model doesn't have brake pads like you would have in a car with disk brakes. It has a multi-disk pack, sort of like a motorcycle clutch. It's like stacking up multiple double-sided clutch disks and using a spring to keep the pressure off of the surfaces, and pressing on the brake pedal overcomes the spring force and forces the surfaces of the disks together. They are located inside the axle trumpets just outboard from the rear axle center housing, inside that fatter part of the axle trumpet hosing before it gets narrower where the fender mounts.
 
..... I also need to rebuild the steering valves ....

I plan to look into my steering this weekend. Since I hadn't used it in a couple of years, I wasn't surprised that the steering seemed slow to respond. I topped off the fluid ( fairly low) and it still was sluggish. Then I drove it on the road and had trouble keeping it going straight. I checked the manual and found that in case of pump failure, the steering motor acts as a pump so you have "some" steering. I'm going to start by changing the filter. I haven't changed it since I've had the machine (over 10 years). Rebuilding the steering motor looks to be a real dicey operation. If that looks to be the problem, I "may" try and rebuild it but keeping replacement as Plan B. $500+ for an aftermarket motor (NH dealer is over $1200) but I've learned that some times it's better to bite the bullet and spend the money. Same goes for the steering pump (300+)
 
Rebuilding the steering motor looks to be a real dicey operation. If that looks to be the problem, I "may" try and rebuild it but keeping replacement as Plan B.

I just "rebuilt" mine the other day, which is to say I took it apart, cleaned it, and put it back together. My steering deteriorated to only one direction.

It was probably a waste of time, because the only wearable parts in there really seemed to be the seals, which I didn't replace since I didn't have them. However, all they do is prevent leaking out of the top of the motor.

To get it out you have to take the covers off the steering column, remove the wheel, and pull the steering column "tube" up to reveal a pin that's held in with a spring clip. Pull the pin and the motor unbolts. I didn't, but clean the outside well first.

It was kind of interesting to see what was inside, but there wasn't any dirt or anything that seemed clogged in there. I blew everything out with an air hose and cleaned them with gasoline nonetheless, and it went back together relatively easily. Have the parts diagram handy though.

My steering fluid had water in it, and I am also cleaning out the pump, rams, and plumbing. When I get it all back together, I'll post my findings. I might put new seals in the pump too.
 

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