John Deere 755 Newbie

[beenthere]

Also use the google search in TBN (upper window) and type in JD 70 FEL.. past threads will come up as hits.. such as

https://www.tractorbynet.com/forums...erating/36340-removal-70-loader-jd-955-a.html

Post a pic of what you have in front of you and it will also help with suggestions and hints how to proceed.

 

[JD755]

70 Loader instructions attached. Note that you need to use the loader to raise the front tires off the ground when latching/unlatching the loader.

 

[buickanddeere]

obtain and read the JD service manuals from Sharps or from 1-800-522-7448. Bubba’s opinion is not always the design engineers intention.

TractorData.com John Deere 755 tractor information

 

[hotrod1016]

 

[Moukie]

Huge help Team - thank you. I think i have all the fittings to manually check oil pressure; just need daylight and time away from work. Hope to check tonight. Once i get that, i will make decision whether or not to remove FEL and begin tearing stuff apart, or plan B.

Thank you very much. I will be back.

David in SC

 

[Moukie]

Update to where i am. Got the FEL off with no issues. Thank you so much for the video hotrod1016! One less oil leak, setting until i get time and parts to fix; should be easy enough........Now for the oil pressure. I finally got a manual gauge and ran tractor a little today. Sure enough, psi is about 18-20 at start, and drops to right at 10 psi on a warm engine at mid-throttle; hence the idiot light coming on. It is doing what it should. My pressure fluctuates with RPM; from about 11-12 at WOT to about 5 at idle. Is it safe to assume from this that oil pump screen can be ruled out? Sounds more to me like worn rod and main bearings? Please help me with some options/advice:

1) Run as is. Maybe it fails; maybe it doesn't. I only expect to put about 30 easy hours per year on it. What would be the failure if it fails?
2) Go from current 15/40 to maybe a 20/50 wt oil. Should i first remove valve cover to make sure oil is reaching rockers?
3) Replace rods and mains only? Is there potential harm in changing only worn rod and main bearings? Can mains be changed in the machine? Do i have to buy from a JD dealer?
4) What about oil pump? Can it be worn, blocked, causing low psi? I am not sure how to test/verify. Can it be changed from the bottom?
5) Bottom end overhaul, to include pistons, sleeves, rod and main bearings, etc.
6) Full OH, including head rebuild.

I have not done compression test to see if head rebuild is needed. Is there potential harm in overhauling bottom without re-working head?

Do all parts have to come from a JD dealer? i contacted Hoye about an engine kit for a 3TNA72UJ Yanmar. As soon as they asked what tractor it was for, the conversation immediately shifted to me having to get parts from a JD dealer.

All suggestions are welcomed. I don't have too much in this tractor yet, and really don't want to put too much in it. It may be best for me to cut my losses before they get too big?

Thank you,
David in SC

 

[pmsmechanic]

I would pull off the oil pan and the bearing caps furthest away from the oil pump. Those will be the bearings with the most wear. If there are no scratches in the bearing journals that you can hook with your finger nail then I would just roll in new rod and main bearings and replace the oil pump and see what happens when you run it. I would also look for an internal oil leak. That might be the cause of your low oil pressure.

I'm just throwing out ideas. Someone with more experience with these engines might have better ideas. I've never worked on a 755.

 

[pipsqueek]

Do all parts have to come from a JD dealer? i contacted Hoye about an engine kit for a 3TNA72UJ Yanmar. As soon as they asked what tractor it was for, the conversation immediately shifted to me having to get parts from a JD dealer.

Hoye has industrial engine part division, lists the engine parts for the 955 (3TN84UJ) with JD part numbers but not 3TNA72UJ, have listing for 3TNA72. JD parts for 755 engine cross to parts for 455 engine, pistons, rings etc.

Yanmar Industrial Engine Parts: Water Cooled Engines

https://www.mytractorforum.com/53-john-deere/767994-need-engine-rebuild-kit-jd-755-a.html

https://www.mytractorforum.com/53-john-deere/600386-new-me-855-a.html

755 engine block where used according to jd parts:

020DF - ENGINE, OEM (SERIES 200 DIESEL)
3009, 3011, 3012, 3014, 3015, 4019 and 4020 OEM Engines and Accessories (Waterloo) - PC2370
3009DF - ENGINE, OEM (SERIES 200 DIESEL)
3009, 3011, 3012, 3014, 3015, 4019 and 4020 OEM Engines and Accessories (Waterloo) - PC2370
3015DF - ENGINE, OEM (SERIES 200 DIESEL)
3009, 3011, 3012, 3014, 3015, 4019 and 4020 OEM Engines and Accessories (Waterloo) - PC2370
3012DF - ENGINE, OEM (SERIES 200 DIESEL)
3009, 3011, 3012, 3014, 3015, 4019 and 4020 OEM Engines and Accessories (Waterloo) - PC2370
3011 - ENGINE, OEM (SERIES 200 DIESEL)
3009, 3011, 3012, 3014, 3015, 4019 and 4020 OEM Engines and Accessories (Waterloo) - PC2370
3014DF - ENGINE, OEM (SERIES 200 DIESEL)
3009, 3011, 3012, 3014, 3015, 4019 and 4020 OEM Engines and Accessories (Waterloo) - PC2370
4019DF - ENGINE, OEM (SERIES 200 DIESEL)
3009, 3011, 3012, 3014, 3015, 4019 and 4020 OEM Engines and Accessories (Waterloo) - PC2370
4020 - ENGINE, OEM (SERIES 200 DIESEL)
3009, 3011, 3012, 3014, 3015, 4019 and 4020 OEM Engines and Accessories (Waterloo) - PC2370
425 - TRACTOR, LAWN AND GARDEN
425, 445 & 455 Lawn and Garden Tractors - PC2351
445 - TRACTOR, LAWN AND GARDEN
425, 445 & 455 Lawn and Garden Tractors - PC2351
455 - TRACTOR, LAWN AND GARDEN
425, 445 & 455 Lawn and Garden Tractors - PC2351
655 - TRACTOR, COMPACT UTILITY
655, 755, 756, 855 and 856 Compact Utility Tractors - PC2054
756 - TRACTOR, COMPACT UTILITY
655, 755, 756, 855 and 856 Compact Utility Tractors - PC2054
755 - TRACTOR, COMPACT UTILITY
655, 755, 756, 855 and 856 Compact Utility Tractors - PC2054
855 - TRACTOR, COMPACT UTILITY
655, 755, 756, 855 and 856 Compact Utility Tractors - PC2054
856 - TRACTOR, COMPACT UTILITY
655, 755, 756, 855 and 856 Compact Utility Tractors - PC2054
670 - TRACTOR, COMPACT UTILITY
670 and 770 Compact Utility Tractor - PC2227
770 - TRACTOR, COMPACT UTILITY
670 and 770 Compact Utility Tractor - PC2227
F925 - MOWER, FRONT
F925 Front Mower - PC10378
3TNA72C - MOWER, FRONT
F925 Front Mower - PC10378
F935 - MOWER, FRONT

Note 425/445 is just because 455 lumped in with that family of tractor. Same with 655/755/855, have to drill down to part section.

 

[Moukie]

I have a very knowledgeable person recommending to me that I swap 15/40 to straight 30 Rotella and I will get better psi. I have a lot of trust in this person's abilities. Does not seem to make sense to me. He also states that 10 psi should be plenty, and not to worry about it.
Any thoughts on this, from you all that have a lot of experience with these engines? I really want to use this machine, but shudder at the thought of using something that is not quite right. I also fear that if I end up pulling the engine to swap rod and main bearings that I will then end up with a total rebuild including head work. That is money I will likely not ever get back during a sale.

Can rod and main bearings (and rear main seal) be changed without pulling the engine?

Also - where is best place to purchase tilt cylinder and power steering cylinder rebuild kits? I need to do all 3 to stop the "bleeding". Can I do this without special tools?

Thanks for the help.
David in SC

 

[Mechanos]

You can get the seals for the loader cylinders from JD. They are an "off" size so source them elsewhere is more difficult but I wouldn't say impossible. As for the power steering cylinder, the gland is welded on, so in order to rebuild it, you'd need to cut the gland off, size and source the seals and then weld it back together. Or source a completely different cylinder altogether.

 

[pmsmechanic]

In school we were taught that 10 psi oil pressure per 1000 rpm was adequate.

 

[Agvg]

30w is thicker when cold but thinner warm than 15/40 so it doesn't make sense. But are your bearings worn your crankshaft is probably also worn and needs machining or replacement.

Have you measured the pressure?

 

[Moukie]

Thanks for all info. Mechanical pressure gauge measures 10-12 psi at operating temperature and WOT; too low for me to be comfortable, so I will likely tear into at least the bottom end.

As for cylinder leaks, no problem buying the tilt cylinder seals from JD. The ps cylinder - wow, welded together. Time for me to get out my saw and welder to give it a shot. Does anyone happen to have the numbers/count for the seals that go back in? Sure makes it nice to have everything laid out and ready before I take it apart.

Thanks so much. This is going to be fun. Happy Pumpkin Day to All!
David in SC

 

[Moukie]

Update on where i am:

1) I have replaced missing glow plug control module. Have not yet tested plugs; but hope to today. Pleased to see the dash light actually came on. No chance of cranking today without glow plugs, as temps will not hit 50.
2) Have re-packed both tilt cylinders. Have not yet put back on, but will soon.
3) Have scrounged metal i need to re-condition bucket
4) Am thinking serious about "siping" the rear tires to give this machine some traction. I can't even hardly maneuver in my backyard without spinning. Don't want to switch to ag tires, as they are too aggressive.
5) Figured out why i have no tach/hour meter. The brass fitting that houses the gear that drives the cable was not seated at all in the base; so the gear was not engaged at all. Housing is all full of crud. Cable inside was actually not broken. I have cleaned it all up and have it ready to put back in. How far in does the brass fitting insert? Hard to tell exactly; there is a ring around the brass fitting; almost like an o-ring groove, but no clearance for an o-ring. It does appear the brass fitting should recess some amount into the base. I can possibly measure and get close. My manual does not show any pics of this.
6) Have sheet metal to fabricate the missing engine cover. Both appear similar, so should be able to do. Just takes time and patience. I have neither, but love to tinker when i can.
7) Went to JD dealer yesterday and bought new fuel filter, hydro oil and filter, and another oil filter......in anticipation of pulling oil pan to measure bearing clearances. Whoa. Dealer quoted me over $300 each for rod bearing inserts! I looked at him like he was an alien and he said "yeah, they are expensive". My plans are now changing. I think i might now just take a chance on it and run the heck out of it and see what happens. No way in the world i will spend $2,000 to replace 6 bearing inserts and a rear seal. That is crazy.

I hate to be cynical, but that is absurd. Couple questions as i seek alternatives:
1) What will likely be my failure for running with low oil pressure? Spun bearing, crank damage?
2) I see the Yanmar engine code of 3TNA72, and i think the UJ at the end only indicates it was used for John Deere applications. If that is true, i would assume the internals of all 3TNA72 engines to be the same. Does that seem reasonable?
3) If that is the case, i see complete engine rebuild kits on ebay for about $500. Yes, they are from China, but what isn't nowadays. Shoot, i can buy a complete rebuild kit for the price of two rod bearing inserts from JD. Any thoughts?
4) Another option is to purchase a donor engine. Again, i can find 3TNA72 engines easier that 3TNA72UJ engines. Is the base engine the same?

Yeah, i am very frustrated with pricing of replacement parts for this machine. But, still moving forward. If i can get comfortable with engine oil pressure, next will be to tackle the non-working front drive axle. That will be exciting.

Thank you again in advance. All feedback is welcomed.

David in sunny, but cold SC

 

[Agvg]

10 - 12 psi at idle? Have you checked price on bearings from a engine shop?

 

[shooterdon]

I feel your pain and frustration. As a new JD855 owner I have been shocked at the repair/parts costs. Fortunately, I got my tractor at a very reasonable price so it softens the blow a bit. Still....It makes purchasing a used older tractor a crap shoot. I nearly bought a second machine that was only going for $3800 that had no attachments and was in better condition than mine. I thought that was a lot of invest for a backup or parts machine...but maybe I should have got it.

It makes buying new and having a warranty look better all the time. I suppose that is part of the marketing plan....make repairs so expensive that people give up on the older machines.

BTW, I have over $2200 in repairs so far. Still no parking brake and will need to do the FEL cylinders eventually as they have slow leaks. No glow plug light and fuel gauge does not work.

 

[hotrod1016]

John Deere outsources a lot of parts. I have invested over 2,000 fixing the 4wd on my 755 and then after 3 1/2 months one of the outsourced beating failed. Cost me another 400 because John Deere only has a 90 day warranty

 

[beenthere]

Good morning,
Proud new owner of a 1989? JD755 that is in need of a whole lot of attention. I think I got a fair deal on the purchase that makes it worth the effort, but it sure needs a lot of work. ..............................................

Truthfully, i love a project and cannot wait to get started. Don't take my post as a negative; just a simple list of what lies ahead. As soon as i figure out how to get the loader off, i will likely take about everything off/apart to get working properly.

......................... Thank you very much, in advance.

David in SC

Went back and read your OP. Hope you are not getting discouraged and won't give up on your project.

 

[Moukie]

Just checking in.....
Great suggestion to check a machine shop for bearings. I will do that.
I am not getting discouraged; just a bit anxious. I just clicked purchase for 3 new glow plugs, as my module appears to work, but all 3 plugs had essentially no resistance. That should be a win, I hope, when they come in. I also got the tach cable gear re-seated properly today, and did a little more cleaning while at it. Good opportunity to remove and check belt and then tension properly.
I am only getting anxious because I am fixing all the little things to make the machine more reliable/useable, but I know the first time I take it out and work it, it may suffer a catastrophic event due to low oil pressure. I refuse to spend the kind of money JD dealer will want for a new JD engine rebuild kit. Shucks, I can buy a complete engine rebuild kit from China for less than the price of two rod bearings from JD dealer.

I would love to hear some feedback on the quality of the rebuild kits I see for around $500 on ebay; especially from someone who has used one. Even if I just used the bearings and threw the rest away, I would come out much better......if the parts are made of good quality.

Anyone have any experience with these kits, and does anyone know if they even work for a JD 755?

Thanks much,
David in chilly SC.