924GZ wheel loader hydraulic problem

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This topic contains 3 replies, has 2 voices, and was last updated by  Ben 3 years, 7 months ago.

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  • #25577 Reply

    Hi All,

    I hope you don’t mind, I’m not a mechanic, I’m translating for a neighbor here in Paraguay, South America who runs a few pieces of heavy equipment (he started out as a mechanic), but doesn’t speak English.

    He has two 924GZ wheel loaders (both he got used). The first one runs fine in all ways, he’s using 15 W 40 oil for the hydraulics system.
    However, the second one has no strength behind the hydraulics and the hydraulic fan quits frequently.

    He cleaned and blew out everything and replaced the oil it had when it showed up (with 15 W 40, he doesn’t know what it had when it arrived). He tried the Cat rep here, but they charged him a fortune and left it worse off than when he gave it it them.

    The machine supposedly had 4500 hours on it, but the marker is broken and he suspects at least twice that really.

    He’s hoping it just needs a heavier oil due to normal loosening up, but as the oil change would be expensive (business is even tougher here than it is in the USA right now) he’s hoping to see if there’s something else he should check, or what other problems it could be…I sort of wonder about the pumps (for the shovel or the secondary for fan and brakes), but I’m no mechanic.

    I appreciate any help you can give us, my neighbor is a guy who came up from nothing (he speaks the Indian language much better than he does Spanish) and is trying to get something done with his life, and that’s really diffficult here. I figured you all wouldn’t mind giving him a hand if you know of something that might help. Thanks.

    #27788 Reply


    Ok so without a hydraulic schematic or ever having worked on one of these machines. If I had to guess… and I hate to say it, or to jump to this conclusion but you’re probably on the right track when you mentioned the pump… it really depends on which functions are giving your friend trouble… knowing that will help narrow down the problem.

    I would have expected the dealer to have a look at something as obvious as that…. but then I don’t know how the dealers are out your way.

    However, if he is having problems with all of the hydraulics the first thing he’ll want to check is the inlet screen for the hydraulic pumps. It’s posibble that all the pumps use a common hose to get their inlet oil. This will most likely be found in the tank, he will probably need to drain the oil. He may also need to remove the inlet hose (I’m not sure exactly where the filter is, I don’t work on CATs) If this filter is cloged or colapsed it could cause this type of problem.

    If it’s the worst case senario and one of the pumps is not working properly I would recomend that he not use the machine until he can fix it because the pump will likely be shedding pieces of metal (brass, steel) and this could contaminate the entire hydraulic system… bits of metal getting stuck in the valves is really not good and he could have ongoing problems for a long time after he fixes it…

    One last thing, as I understand it CAT does recommend 15W40 for it’s hydraulic oil however this is already a pretty thick oil, even for warmer climats so, I don’t know if changing the oil is really a good idea. If the problem is the pumps changing the oil may help for a short period of time but will also allow the pump(s) to wear out even more and that may cause more problems later as I said in the above paragraph.

    Anyway I hope some of this helps. Good luck to your friend.
    Please let me know if I helped or if you/he have any more questions


    #27801 Reply

    Thanks, Gadget!

    I’lll pass this on to him. There are separate lines for the bucket versus the fan and brakes, and he’s had problems with the fan (cuts out frequently) and bucket (lacks power), so I think it isn’t a single inlet screen, but everything else you said will help him track it down. I found one Cat manual that used an example of a 924GZ using 10W hydraulic, but there is no plainly spelled out recommendation (not even in the operator’s manual, which he has).

    This neighbor of mine is a real hard worker trying to get something done in life, so I’m glad for a chance to help him, and I’m really grateful to you for taking the time to lend a hand. It really helps.

    #27802 Reply


    No problem, I really hope it does help…

    Please get back to me and let me know of any progress, I’m having beers with one of my buddy’s tomorrow night, I’m pretty sure he works on these machines so I’m going to run this problem by him and see if he has any ideas…


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