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going to look at a D65E-7 this weekend- advice on what to check?

Discussion in 'Dozers' started by LCA078, Feb 25, 2021.

  1. LCA078

    LCA078 Well-Known Member

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    A D65E-7 is up for sale locally and the price seems right for a ranch dozer (ie- way under what a decent Cat D6 is going going for here). The guy selling it is a consignment yard so I'm not relying too much on his description of it being a great machine with 7k original hours. Anything specific to look for besides the basic u/c wear, fluids, engine starting/sounds, and shifting through all gears? I think it's a grey market machine so not really sure what engine it will have until I see it in person.
     
  2. tctractors

    tctractors Senior Member

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    The Series 7 has the Komatsu S6D125 motor, the low hours you talk of would not be an issue to any component on this Mount.
    tctractors.
     
    John C. likes this.
  3. LCA078

    LCA078 Well-Known Member

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    Thanks for the quick reply, tc- I was hoping you'd chime in on this one.

    The consignment yard is describing it as a -7 even though the serial number isn't showing up in the literature- that's why I think it's a grey market machine. From looking at other -7's for sale in machinery trader, I'm fairly confident this is a -7 and should have the S6D125 motor (which I understand is a good thing). With no electronic controls, emissions, etc. and it also being a main model for Komatsu, I don't think being a grey market is too much to worry about. If I'm wrong and maintenance might be painful, please correct me.

    Hopefully I can see it in person this weekend and post some pics of any leaks or worn-looking parts for your input. My main concern will be that I doubt I'll be able to put under load in the consignment lot to bog it down. Any way to test the tranny or engine instead of pushing dirt or leaning on a big stump? Should I try to test any pressures? (if so, let me know the fitting sizes I need to bring- I have a 0-5k psi gauge).
     
    Last edited: Feb 26, 2021
  4. tctractors

    tctractors Senior Member

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    The chance to fit pressure test points into the filter lids under the floor plates might prove a point to far to go, so just do a stall test and hope the drive shaft locks up, in first gear it will drive through the brakes on full bore.
    tctractors.
     
  5. LCA078

    LCA078 Well-Known Member

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    Thank you. And just to ensure I understand what you mean for a stall test I'm hearing:
    -In second or third gear, the brakes should readily stop (stall) the dozer.
    -In first gear at full throttle, the brakes probably won't stall it and it'll creep forward.
    -In first gear at med or low throttle, the brakes 'should' stall it.
    -If the drive shaft spins with the tracks stopped, it means a clutch is slipping.
    -If the drive shaft stops spinning when the tracks stop, the clutches are holding up against the torque convertor and the engine better have a bogged-down sound.

    I'm trying to think of a scenario where the engine bogs down to the point it dies with the brakes locked up but I really can't think of something unless the engine is weak (for a non-direct drive machine anyway).

    I'm guessing there's an art to listening to the engine, watching the tracks and drive shaft spin during a stall test to decipher the weak link (engine, torque converter, clutches, etc.). Looks like I'll be learning on the fly!
     
  6. John C.

    John C. Senior Member

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    It sounds like I should do a video tutorial on running stall tests on machines with a torque converter. If you can kill the engine with a torque converter engine, you got lots of problems.

    Something in my head is reminding me of a three stage torque converter in these machines. Does anyone know about that?
     
  7. LCA078

    LCA078 Well-Known Member

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    John- videos would be amazing for future readers. For me, I can find my way around most old-school diesel engines and understand how torque converters work. Where it gets a bit fuzzy is understanding the complete drive train on older dozers.

    For instance, my understanding for a simple dozer with a tc: Power is transmitted from Engine --> Torque Converter --> Transmission (gearing) --> Steering Clutch Packs --> Brake Packs --> Final Drives --> Sprockets --> Tracks. I get there are variations with steering and brake arrangements but in short, the engine should continue to spin even when the rest of the system is stalled (stopped). In this case with a correctly functioning driveline, the drive shaft should not be turning and the engine is bogging down a bit.

    But to add to further fuzziness, I understand some dozers have integrated controls where pulling a steering clutch all the way back engages a brake. What I don't know if fully engaging a brake disengages a clutch. That would make sense to me....but I never designed a dozer nor actually turned a bolt on one so what makes sense to me is pretty much worth squat.

    Maybe that'll help design a video if you go that route.
     
  8. John C.

    John C. Senior Member

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    The converter is a type of fluid coupling that can allow for slippage between the engine and the transmission. When you apply full power or torque from the engine, it is applied to the converter which transfers it to the transmission. When the transmission has resistance to turning in the form of a load against the blade or someone stepping on the brakes, the fluid in the torque converter starts slipping or shearing between the internal elements of the converter. The angles inside the components are engineered so that torque is increased for a bit but only up to a limit. The load is applied to the engine which will drop down some in revolutions. There are factory specifications for how many revolutions the engine drops and that spec can tell you the efficiency of the engine and torque converter. Stalling the converter also creates heat. You can get a feel for the efficiency of the converter by how fast that temperature rises and how fast it cools down again when the load is released.
    Now you have two factors of operation that can give you a good and quick read on possible problems in those two components.
     
    Paul Council likes this.
  9. LCA078

    LCA078 Well-Known Member

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    I saw the D65E today and it was in okay shape for a 40 year old machine. After figuring out the monkeyed-up electrical system, the engine started okay and hydraulics seemed to be good. Undercarriage had significant wear and blade was beat to hell with big slop in all the pivot points. Shifting was very stiff and seemed out of decent adjustment (like neutral was near the 1st detent, and 1st was near 2nd, etc.). All that was okay but what bothered me was that both brakes were mush with barely any resistance all the way to the floor and didn't stop/slow the machine at all in any gear. Machine was slow to turn left and didn't turn right at all with the steering levers. Also, there was not a stump/ditch/mound of dirt to push against either so I really couldn't figure out how to do a stall test with the bad brakes nor put any load on it for a bit. Seller said the brakes and steering weren't really needed when pushing dirt (blade tilt was all you needed to steer) but were also an easy fix with a simple adjustment in the linkages...all to which I politely agreed. I didn't know how to play with the linkages nor troubleshoot the brakes and I was short on time so I left feeling fairly dejected. But given the seller's hard price is over 2x what similar ones have sold at auction, I'm pretty sure it'll be there for a while. If I can understand how to troubleshoot the brakes and fiddle with the steering linkages, it may be worthwhile to go back and take another look if the seller comes down in price.
     
    Last edited: Feb 28, 2021
  10. John C.

    John C. Senior Member

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    The adjusters are under a cap on each side of the back of the machine on top of the main deck and underneath the fuel tank. It's not something that is difficult to do but there is the possibility that the linings on the bands are worn out as well.

    If they are asking too much and don't hesitate to walk away.
     
  11. epirbalex

    epirbalex Well-Known Member

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    hours sound crook
     
  12. LCA078

    LCA078 Well-Known Member

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    two very good bits of advice right there...
     
  13. ETMF 58 White

    ETMF 58 White Well-Known Member

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    Sounds like you are making the right call here. More advice for anyone reading who wants their own farm dozer, ranch dozer, build-a-pond behind the house dozer: You can’t do decent work with a sloppy blade. You can’t get much work done with a too-small machine. You can’t get any work done with a broke down machine. You can’t imagine how expensive repair bills are on these things. You will get very little help from dealers on old stuff owned by DIY’ers. BUT, a nice well cared for reasonably aged dozer will give you much satisfaction and be very handy to have around. You can’t go cheap in this business.
     
    Shimmy1 likes this.
  14. Shimmy1

    Shimmy1 Senior Member

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    I know we aren't discussing one, but I have a question for the guys that are familiar with cable blades. Isn't any machine with a cable blade considered "sloppy"?
     
  15. John C.

    John C. Senior Member

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    A sloppy blade doesn't mean that it can't be used. Put a couple of thousand hours on any dozer and they loosen up a bunch. Unless you are running a GPS or trying to use the dozer for a grader, the loose blade joints aren't going to stop you. The dirt don't care what is moving it.
     
  16. LCA078

    LCA078 Well-Known Member

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    John is right for what I’ll be using it for. Slop in the blade probably won’t affect my ability to push cedar into a burn pile. And even this was a brand new dozer off the show room floor, my non-experienced hands on the controls will cause more damage than anything else could.

    The slop I’m worried about is a trunnion or pivot point being so worn that it’ll slip out or off during a push.

    I’m sure someone willing to put some love and a lot money into that machine will have a great machine.