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Cat 977L Fuel Leak

jezow2010 · 2022-12-30 13:32

Hello, we are looking at potentially buying two Cat 977Ls - one serial is 11K05182 and I cannot find the serial on the other although I am sure it is similar. long story short we don’t know the story and we know nothing about these larger CATs. One machine fired on ether but as soon as we got it to fire a little it started pouring fuel out of what seems to be a weep hole out of the transfer pump? It’s just a line that runs into the belly pan. Am I correct in assuming it’s a weep hole and is there no fuel return from the pump area on this system? All I can see is the fuel line incoming from the tank nothing else. It was smoking, I’m assuming it is getting fuel and is a runner we just didn’t have the best batteries and didn’t know what to think when it started dumping fuel. For the sake of seeing if it will run, move forward and backward and steer, I think I will just run this line into the tank or a catch and let it bleed for the few minutes we run it. Lastly, what else do we need to look for if I may ask? The other machine is seized but being able to buy them both makes me comfortable that I will have parts to keep the one good one running. I will check the fluids, try and check operation etc. but if anyone has some advice I am all ears! also, what manuals would you recommend I get? I have been trying to download a nice service manual so I can look at the fuel system schematic and diagrams of the fuel pump but I think I will have to order a hard copy somewhere. Thanks!! Tyler

Replies42
  1. #1Nige2022-12-30 13:52

    Here's what to look for based on the 11K05182 S/N. The same manuals might apply for the other machine but that is not guaranteed. See comments below. SEBU5374 - Operation & Maintenance Manual - $30 UEG0732S - Parts Manual - $124 REG00635 - Service & Repair Manual - $200. Prices quoted are for pdf downloads and/or CD as appropriate. The service manual is not available for donwload AFAIK, the nearest option that is not in paper form is on CD. The 11K prefix covered both 977K and 977L loaders. There are 4 different ranges of the 11K prefix, 1-3918 that are badged as K model, 3919-5050, 5051-7762, and 7763-Up. The last 3 groups are all L models. Different manuals can apply to different groups, especially for parts. You may find some useful information in this link - https://tractors.fandom.com/wiki/Caterpillar_977K

  2. #2Nige2022-12-30 13:53

    Keep posting.......... As a new member once you have made 3 posts you will be able to upload photos. At that point get snapping and let everyone else see what you see.

  3. #3fest7772022-12-30 15:46

    could be a bleed line, is there a petcock on the pump end may need too shut it off

  4. #4jezow20102022-12-30 15:58

    There is the air bleed at the top, I’m assuming, just like a round knob you turn. I never did check what position that was in and whether or not that would change things.

  5. #5jezow20102022-12-30 15:59

    Thanks for the source for the manuals!

  6. #6Cat9772022-12-31 15:14

    The undercarriage is the make or break deal. Post pictures. 8" pitch from 11K1 to 11K05958 the SALT track witch has 8 1/2" pitch. But I've seen 2 old machines with the 8 1/2" pitch. The 8" pitch replacements will be phased out, if they haven't been already. Don't bet the farm on this info but it may help. The Caterpillar 977K crawler loader was introduced in 1966 in the USA. Production began in Japan in 1967 and Scotland a year later. [1] The 977K has a D333 turbocharged , six-cylinder engine producing 170 hp (130 kW) (FWHP). It has a three-speed powershift transmission. It comes standard with oil cooled clutches and brakes, pedal steer, and electric start. The 977K was manufactured in the USA, with an 11K or 46H serial number prefix; in Japan with a 70J or 76H prefix; and in Scotland, with a 48J prefix. The 46H unit has a walk-through operator’s compartment. In 1970 Caterpillar modified the final drive, beginning with 70J00569, 48J00376, and 11K03019. In 1971 a sealed loader linkage was added, beginning with 70J01083, 48J00584, and 11K03687. Caterpillar replaced 977K with 977L in 1971, but retained the 977K serial number prefixes. The 977L features increased horsepower to 190 hp (140 kW) FWHP, beginning with 70J01303, 48J00586, and 11K03919. In 1970 Caterpillar modified the final drive, beginning with 70J00569, 48J00376, and 11K03019. In 1971 a sealed loader linkage was added, beginning with 70J01083, 48J00584, and 11K03687. Caterpillar replaced 977K with 977L in 1971, but retained the 977K serial number prefixes. The 977L features increased horsepower to 190 hp (140 kW) FWHP, beginning with 70J01303, 48J00586, and 11K03919. In 1973 a rollover protection system (ROPS) was added to the American unit, beginning with 11K05417. Cat also added a two-piece master link, beginning with 11K05959.

  7. #7jezow20102022-12-31 15:38

    Undercarriage is surprisingly ok for as much as we would use them. The price is right… I would hate to see them to to go to the crusher and we could definitely have some fun with them. Not sure when we will go look again, next time hopefully we can fire the one up fuel leaks aside and make a deal and get them home!

  8. #8Cat9772023-01-01 10:22

    I think those tracks are stretched/worn. The sprockets are worn way out from it I believe. The chain probably skips teeth under the load of pushing, on both of them from the distant pictures. You could post better ones. I would advise getting a look see from a pro or you may be fighting your way up a long list of bills. Just replacing the sprocket won't work the old chain won't match the new sprocket and will climb up on top of teeth snapping and grinding, and something will break after too short a time. I have some older segments I may sell cheap or look on Machinery Trader for some used ones. "Don't even try New Ones" Absolute best of luck whatever you decide!!

  9. #9Dave Neubert2023-01-03 16:49

    check to see if bleeder is open if it is closed then supply pump needs replaced or rebuilt

  10. #10jezow20102023-01-03 20:02

    Yeah that’s what I read, can you tell me where, for sure, the bleeder is? There are two things that I can see clearly - a knob that I can turn which I’m assuming is the bleeder, and then a pump to prime things. Is that the bleeder?

  11. #11Delmer2023-01-04 01:08

    yes, a knob you can turn could be a bleeder. Turn it clockwise and see if it shuts off the fuel. Not unexpected that somebody trying to get it started would open that and leave it open if they couldn't get it working.

  12. #12Nige2023-01-04 10:32

    Is this, or something similar, what you have.? #1 is the bleeder valve. It is a needle valve and may be damaged or not seating correctly.

  13. #13Nige2023-01-04 10:36

    Here's a slightly different illustration of what you may have. #23 is the priming pump. The knob is unscrewed anti-clockwise to release then pump to prime and at the end crew it clockwise until it tightens.

  14. #14jezow20102023-01-04 10:38

    That does look like it. So when that bleeder valve is open it will not bleed around the valve but down to a drain? I am going back out Friday, I will be able to share more then!

  15. #15Nige2023-01-04 10:48

    Take some good photos so that everyone else can see what you're looking at.

  16. #16jezow20102023-01-07 15:18

    Ok we went back yesterday. Few things - 1. The fuel pump on the first machine definitely needs rebuilding. Someone in here said the seals were bad and that has to be the case… it is leaking fuel everywhere out of the transfer pump once it gets going. Fuel leak solved. 2. Said machine has either a rod knock or a broken piston. Sounds horrible but it had good oil pressure. Other than that it turned and moved forward and back but that’s it. Rest in peace. 3. The other machine is locked up from sitting. It would turn slightly but needs a little more work. If I were to unscrew the glow plugs does that give me access to the pistons to put some penetrating oil down the cylinders? If so I may go back and try. 4. The undercarriage on the seized machine is marginal, pics attached. These machines are headed to the shredder unless someone is interested, I do not think I am so much anymore. $5k each based on scrap value if anyone is interested. I will also link a YouTube video once it is uploaded.

  17. #17jezow20102023-01-07 15:20

    More pics

  18. #18DMiller2023-01-07 17:30

    What ever went thru the gear train on the last few photos may have wiped out a worthy overhaulable engine, timing cover busted, mounting plate bent and injection pump who knows. SALT rails, may have some life left internally Pin to Bushings, need to look at bushing wear and if any of the seals have failed with oily greasy residue inside the link ears. Sprocket segments on the Dozer Shoe unit are pointing, around 60-70% worn, rollers would need to be checked for frozen or busted flanges on that unit. Large Tooth Shaped rail section is the Master Link, remove the rail shoe bolts and beat the dickens out of that to separate to remove a rail. To measure Rail wear, get the rail tighter, across four segment(five Pins) measure as close to Ctr to Ctr or edge of a pin to same edge of a fifth pin away and divide by four. Either one of those and or both will be MONEY pits for awhile to get 'Functional Enough' to work.

  19. #19jezow20102023-01-07 17:57

    This shows a lot more - CAT 977 cut 01 the pictures of the messed up engine are what is left of a cannibalized/half scrapped machine but it shows the fuel system that is on the other. Amazingly enough it turns over haha.

  20. #20Nige2023-01-07 18:01

    Anything's fixable. This thread should give you a few ideas - HeavyEquipmentForums If you can get the pair for scrap value there ought to be possibilities.

  21. #21jezow20102023-01-09 18:38

    Can anyone weigh in on popping the glow plugs to access the cylinders with some lube? How is everything else on these machines? Are transmission and brake issues common? Are the final drives really a problem point? The oil in these looked mint. If you want to replace tracks what are your options and how much money would you plan on?

  22. #22Nige2023-01-09 18:42

    HEF's tame fuel injection specialist was opining not long ago about an easy way to remove glow plugs. Let me see if I can find a link. Either way removing the glow plugs would allow lubricant to be injected directly into the cylinders.

  23. #23Delmer2023-01-09 22:50

    Tracks will cost more than the machine is currently worth by the time you're done, and you might not get the cost of tracks back if you have to sell in a few years, total. You have to have some serious work to be worth keeping one of those running. Now, if you enjoy working on stuff like this, you could possibly make one good one and keep it going with parts. "scrap value" is not the weight times price at the yard, "scrap value" is what someone is willing to pay to come and remove a very large and hard to move carcass, for negotiating purposes.

  24. #24ChrisUK2023-01-17 05:17

    Thanks @Nige

  25. #25ChrisUK2023-01-17 05:21

    @DMiller that last sentence has hit the nail squarely on the head !

  26. #26DMiller2023-01-17 06:31

    Yep, anything's fixable as long as cash flows!!

  27. #27jezow20102023-01-24 20:53

    Do you have a source where I can find the manuals on CD? Specifically REG00635. Google doesn’t show me much. Machines in their new home -

  28. #28Nige2023-01-24 22:03

    Try here - https://www.servicemanualpro.com/?page=Products&searchbox=11K05182

  29. #29bunkclimber2023-01-26 06:51

    I saw the YT video you posted the 977L runner it didnt sound too bad, mighta just needed a good afternoon snortin' to clear it out..shame about the one with the smashed engine..even the injection pump off of that coulda brought $500 or better as a core..anyway there's still a lot of these 977s out there for sale cheap,I'd pass on these two..unless like maybe if one had a winch..but those are golden hen's teeth anymore..

  30. #30jezow20102023-02-12 18:45

    Ok well too late to pass haha … have the service manual and replaced the transfer pump assembly and the hand pump. Got the system bled out nice and now when you pump the hand pump it just pushes out that same overflow. From what I understand that drains the cavity between the two seals for the injector pump drive shaft. So the fuel side is bad and it’s leaking past the seal and down the outlet. the manual I have is the wrong engine layout… it matches the other 977L but the machine in question seems to be more of a 977K. Picture of the engine serial attached. does anyone have any info on what that seal and cavity looks like?

  31. #31Nige2023-02-12 19:23

    Wrong manual for the engine in 11K05182 or for the other machine.? On which machine is the 3N01759 engine S/N plate.?

  32. #32jezow20102023-02-12 19:30

    Wrong manual for the engine in the 11K05182 machine. That’s the machine the engine tag is from. I’m pretty confused by this… the manual clearly says it covers the 05182 machine but it’s not correct, the machine looks exactly like the K machine that was cannibalized. Is there a chance someone put an older engine in the 05182 machine…?

  33. #33Nige2023-02-12 20:05

    I am almost sure not. I can't date or relate the engine S/N to the tractor Serial Number, but see below. Regarding only engines and ignoring all the other machine changes made during production of the 11K-prefix 977 models........ Machines with S/N from first built up to 11K3918 were badged as K models and had a 170FWHP D333 turbo engine. S/N from 11K3919-5050 were badged as L models, retaining the D333 engine but with power increased to 190 FWHP. For both the above ranges the original engine installed during manufacture of the tractor would carry the same Serial Number as the tractor. S/N from 11K5051-7762 were again badged as L models. The D333 engine was replaced by a 3306 (3N-prefix) engine but retaining the same 190 FWHP. So your 11K5182 with a 3N-prefix 3306 engine is right. Also the 2P8604 engine arrangement on the engine plate is only listed as being for use in 977L machines. Whether the engine is the original one fitted to the tractor is another matter. I suppose the possibility exists that the engine might be a later one than the original engine installed in 11K5182 but as S/Ns go 3N1759 is a pretty early 3306 engine.

  34. #34jezow20102023-02-13 08:33

    So it appears it is just an early 3306… is guess the serial number told me that on the engine *facepalm* any ideas on what manual I need for this specific injection pump variant? I combed my manual last night and it just is based off an entirely different injection pump and fuel system.

  35. #35Nige2023-02-13 09:08

    Can you find any Part Numbers on the injection pump itself, maybe a Part # tag or a casting number on the body.? I suppose that it is possible that a different FIP to the one the engine was originally built with has been installed. 11K machine s over 7130 had a different fuel system (sleeve metering) compared to the earlier models.

  36. #36jezow20102023-02-13 10:51

    That’s interesting and makes sense as to why the newer machine (07393) has the newer, sleeve metering fuel injection system. Just a bummer as to why the manual does not cover both styles. I will try and get a good picture of the FIP in question.

  37. #37Nige2023-02-13 10:59

    What is the pubication reference number of the section of the manual where the "System Operation" ofuel system information appears.? I just checked SENR7593-01 online and it includes both New Scroll Fuel System (NSFS) and the sleeve metering fuel system. I'll send you something. Keep an eye on your messages.

  38. #38jezow20102023-02-17 18:02

    I actually went back to the scrapped machine and tore the entire injection pump off to see if I could find the issue. Few things - 1. for the hand primer pump what way does it go?? The machine we have had the inlet sucking from the fuel filter housing by the bleeder and the outlet went to the injection housing in the fitting near where the fuel comes from the tank. When we pumped it would blow bubbles in the tank. We flipped it to what the manuals show - from the tank is the bottom or inlet side and then it outputs to the fuel filter housing by the bleeder. Now it pumps correctly but unless the breather is completely open it just dumps fuel out of the drain in question. 2. The drain in question, after looking at the casting, has two potential sources - the fuel transfer pump (which is brand new now) and a channel from the fuel filter housing. I do not have this housing at the moment but from what I can tell it’s the drain from a fuel bypass valve? Does anyone have anymore info on that…? 3. how does the transfer pump route its excess fuel back to the inlet? Is it the bypass internal to the pump? If it is through the primer pump then it seems it would have to be mounted ‘backwards’ as we found it on the machine. a good picture of a K or L fuel pump setup would go a long ways in determining the primer pump direction in question.

  39. #39jezow20102023-02-17 18:03

    More pictures, also meant to say if the bypass is messed up and or it goes through the hand primer pump I could have dead headed the new pump and blew out the seal that would cause this leak. To me, it seems as if it’s way too much fuel to becoming from that pump. It seems like the pump is dumping it through this.

  40. #40jezow20102023-02-18 20:22

    In an effort to close this out for some other poor soul that has the same issue as we did… we found the issue. The bleeder was not seating properly and apparently that tube is where is bleeds out. It looks like someone whacked it and bent the threads so when it was ‘tight’ the valve was not seating properly. Got it tightened down and the leak was gone! Unfortunately, the fuel leak did not solve the knock. Looking for a good 3306 if anyone has any leads!!

  41. #41Bluox2023-02-18 23:02

    with the motor running loosen the fuel lines one at a time and see if the knock goes away. If it do change the nozzle on that one . If that cures it change them all. Bad Bob

  42. #42jezow20102023-02-19 08:52

    Take a listen to this - https://youtube.com/shorts/bbGKiE64lRQ?feature=share When I shut it off it stopped very abruptly. I went to turn the fan over and it would not budge as it would before. What is the interchangeability on these 3306 engines? I see different injection systems like we have on the two machines and then I see direct injection engines. Can I put a DI 3306 in place of a PC one?