2019 Gone Farmin' Fall Premier Auction

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Thread: One for the experts - Cat 637D scraper.

  1. #31
    Join Date
    Jan 2013
    Location
    Australia
    Posts
    73

    Default This may help for a start

    That's shame Deas, thought we had it beat.
    Here's the hyd tank detail if it's any use for a start. You've got the fuel lines group yesterday, I guess using it to check there are no more wayward hoses connected incorrectly from the fuel group to the hyd system might be a start. We have established fuel is somehow entering the hydraulic system; it appears that despite the tremendous pressure that builds up in the hyd tank as it becomes overfull, the contaminated fuel/hyd oil canít be forced back into the fuel tank by that tremendous pressure.

    Looking at the schematics, it appears the two tanks don't share a common wall which if they did, could be cracked and allow fuel to be drawn into the hyd tank by suction as the ejector is moved to dump position because those ejector rams are pretty thirsty in terms of oil capacity. But if that were the case, surely it would be contaminating the fuel when the ejector retracts and oil is returned to the tank, which it's not. The fuel tank breather hose - has it been incorrectly connected into the hyd circuit and the suction just mentioned pulling fuel into the hyd circuit? Just a few ideas from a layman Deas.

    637D hyd tank FIN.pdf
    Attached Files Attached Files
    Last edited by OZPHIL2; 09-21-2019 at 02:14 AM.

  2. #32
    Join Date
    Dec 2006
    Location
    victoria australia
    Posts
    3,079

    Default Run Time To Full tank

    Hi Deas,
    seems odd it ran 3.5 hours no problem then suddenly found to be overfull---I guess when the next pre-start checks were done.

    I think it is time to put a Non Cat lock--- that ONLY the Dirt Foreman has access to---on the Hyd tank cap and see what happens.

    Cheers,
    Eddie B.

  3. #33
    Join Date
    Nov 2006
    Location
    Gold Coast, Queensland, Australia
    Posts
    4,767

    Default Doubt??????????

    Hi, edb.
    I doubt that a lock will solve the problem. It is the ranch foreman who has been filling it and I am sure that he knows where the fuel should go as I have watched him re-fuelling. It was 'ackshully' found to be over-full at the end of the day when the sight glass was checked out of curiosity

    I think we are just gonna hafta dig a little deeper, maybe investigate whether there is indeed a return fuel line from the back motor that is coming to the front and has been wrongly connected.

    OZPHIL2 has sent me schematics of the fuel system which I will check out against the machine on Monday. I will also look for other small lines attached to the hydraulic tank that don't look like they oughta be there. Thank you, OZPHIL2.

    If that fails, we may hafta call in the 'ex-spurts', the local Cat dealership - - who quite possibly don't have anyone whose memory goes back that far.

    Just my 0.02.
    You have a wonderful day. Best wishes.

    Deas Plant.

  4. #34
    Join Date
    Dec 2006
    Location
    victoria australia
    Posts
    3,079

    Default Rear Engine Fuel Lines

    Hi Deas,
    OK then on the Foreman--I could understand someone filling the Hyd Tank with Diesel after the Hyd tank was contaminated with Diesel via the so far found erroneously plumbed Injection Pump Return Line--9 Gal Per Hour return rate for the standard orificed fitting--return flow keeps the Inj Pump free from air/aerated fuel and also aides in cooling a little bit.

    A nose test before filling would indicate two Diesel Tanks to the unknowing who filled by nose.

    The Hyd tank/system must be mega diluted with Diesel by now and/or it is costing mega bucks to keep changing part of the oil in the system--wonder if it is expanding and/or aerating due to the very thinned Hyd oil--Hyd Pump cavitation could build air pockets in the bowl lift cylinders sending the expelled/displaced oil back to the Hyd tank.
    I guess the other cylinders have been removed for the water truck application.

    Is the water pump driven hydraulically or mechanically ?

    If by hydraulic motor, then aeration from cavitation may trap air in the Hyd system within the oil itself--can you see air bubbles (aerated oil) in the Hyd oil when dipping the Hyd tank oil with a clean stick or such--must be dipped as the gauge glass may not get to see the aerated hyd tank oil--only the level.
    --I guess one could wonder if the Hyd circuit is really actually over full, and we are not being tricked by expansion due to aerated diluted Hyd oil.


    You fellows are likely more savvy now as to what to look for than an outside person who is not very experienced at troubleshooting such problems.

    Was at The Dealer a week or so back and mechanics are so hard to get here that they have recruited from South Africa--I think-- and stand to be corrected--there was a young lady amongst them. They were doing their orientation, safety training etc.

    Also the usual question was posed when ever I visit The Dealer--"Eddie, when are you coming back ?"
    This even after some 15 years since retiring.

    Cheers,
    Eddie B.

  5. #35
    Join Date
    Nov 2006
    Location
    Gold Coast, Queensland, Australia
    Posts
    4,767

    Default Still a scraper.

    Hi, edb.
    This machine is still a working twin-engined scraper with separate fuel tanks front and rear for each of the 2 engines. We are gonna hafta do a closer inspection to see if we can find some other fuel line wrongly coupled to the hydraulic tank - times like this, I could wish that I was a bit younger and 'scrawnier' but that is also why there are younger and more active people than me around the place, to do those things that I can't.

    I am going to sideline that machine until we do solve this problem in hopes of avoiding any further damage to the hydraulic system.

    Ah, life's little mysteries.

    Just my 0.02.
    You have a wonderful day. Best wishes.

    Deas Plant.

  6. #36
    Join Date
    Nov 2006
    Location
    Gold Coast, Queensland, Australia
    Posts
    4,767

    Default The Mystery Continues.

    Hi, Folks.
    Well, the mystery continues.

    We had a Quinn Cat mechanic out here to look at the 637D scraper last night and he went away with splinters under his fingernails too. It looks as if the hydraulic tank will be coming off next.

    Stay 'tooned'.

    Just my 0.02.
    You have a wonderful day. Best wishes.

    Deas Plant.

  7. #37
    Join Date
    Dec 2006
    Location
    victoria australia
    Posts
    3,079

    Default Split Tank Wall

    Hi Deas,
    thanks for update on this hair tearer.
    By now with all the eyes that have looked at this unit that we can now be fairly sure to assume that the fuel lines etc. are fitted correctly.
    It is logical now to inspect the inner dividing wall in the combined tank setup for a split/cracked wall.
    Would it be true to say that the most leakage has occurred when the fuel compartment has been fullest ??

    Maybe in the past the tank has been damaged and repaired but the inner wall has a problem still--often can be the case for selling on a machine with a seemingly un-fixable issue.

    How long has the Ranch owned this unit ? if a recent purchase then we may have our answer as per the above scenario.

    Cheers,
    Eddie B.

  8. #38
    Join Date
    Nov 2007
    Location
    NW Ohio
    Posts
    3,310

    Default

    Would this unit have a fuel oil torque converter?

  9. #39
    Join Date
    Nov 2006
    Location
    Gold Coast, Queensland, Australia
    Posts
    4,767

    Default Separate Tanks and Oil TC.

    Hi, edb
    The hydraulic tank is separate from the fuel tank and merely bolts to the front of the fuel tank. The fuel tank appears to be part of the fender assembly. As near as I am able to see with the hydraulic tank still in place, there appears to be about a 2-inch gap between them which appears to be open at the bottom and possibly also on the side facing the engine, which I can't see at the moment.

    From the parts book, there appears to be a large access plate bolted to the rear face of the hydraulic tank, the side facing the fuel tank. I'm guessing that this plate is there to enable access to the plumbing inside the hydraulic tank but WHY put it on the inaccesible side of the tank so that you have to REMOVE the whole tank to be able to access that plate? Why not put it on the front face of the tank to make access easier?

    O.K.. I know. I'm just a 'pore, dumm bulldozer operator' so what would I know?

    Hi, Rome K/G.
    I think the torque converter runs on oil which I suspect comes from the transmission.

    Just my 0.02.
    You have a wonderful day. Best wishes.

    Deas Plant.

  10. #40
    Join Date
    Jan 2013
    Location
    Australia
    Posts
    73

    Default 637D Hyd tank pics

    Deas,
    A couple of pics from the net of a wreck. Two seperate tanks as you say. May be of some help.


    fuel-and-hyd-tanl-637D-2a.jpg

    fuel-and-hyd-tank-637d-3a.jpg

    637D-hyd-tank4.jpg
    Last edited by OZPHIL2; 09-28-2019 at 01:44 AM.

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