892D bogging

Hello all, I have a poor decision 892D I purchased earlier this year that I’ve already got some good help on here for. This machine has been a huge learning experience for me. The last big hurdle for me to have a good working machine is a weird bogging issue. Have read a lot and not found anyone else with the same symptoms. The machine goes forward and back great but bogs hard when turning. Also, if I push down with the boom it is too weak to lift the tracks but as soon as I activate another function, like move the stick some, it will pick the tracks right up no problem. Im a novice but this does not seem engine related to me. It seems to run great with only a puff of black smoke on startup and I have changed filters and oil. Also doesn’t seem like relief valve because of the change with the second function. Ideas?

Are you moving the stick then pushing the boom down and it lifts? Or your putting the boom down then curling the stick to lift the tracks?

Push down with the boom, very little power. Keep pushing and also move the stick, plenty of power.

So I finally have a bucket on this and dug a little with it today. I have a major power issue. It bogs lifting the boom just with the bucket. Have to go really slow or little at a time with dirt. I have to lift the tracks to turn. It has a new fuel filter and smokes when it bogs, don’t think it’s an engine issue. Is there anything easy to check or do I need to get the manual printed and start checking pressures?

You need to be sure it is not the engine first. You need to check boost pressure. With the engine at full operating temperature, load the engine to 2100 rpm. Boost should be 17.5-18.5 psi. If it can't make boost, then you have an engine issue.

Ive had a bogging issue my self that was different than yours. The best advice I can give to you is to have someone come to you or bring machine to them and have them thoroughly check the hydraulic pump with a flow gauge. Mine was bogging on stick and boom functions and he adjusted the regulators on both of the pumps as well as the pilot pump. I first ruled out fuel related potentials , then turbo which lead to the next victim the hydraulic pump. Be sure the air cleaners are new, new fuel filters and ck all rubber fuel hoses for cracks to eliminate air suction or line collapse if the fuel lines are old and weak, if theres a banjo screen on inj. pump make sure there no debris it. It seems to me to be a hydraulic problem, but you have to go thru the process of elimination. There's no other way around it. If you can find out the pump manufacturer and get the part # off it is a big help and you need the service manual so a technician can go thru book and see what the settings should be. My Tech said if i didn't have the service manual he would of never of come out, they need those spec's out of the book otherwise they're workin blind. Good luck.

Well, I called a cat mechanic friend cause I don’t have a Deere mechanic friend. He hasn’t made it here yet so I’ve dug deeper, trying to eliminate engine issues to be sure. I plumbed in a boost gauge I had from a car. It made a max of 8 psi which I’m sure is way low. Even worse, the old coolant reservoir was broken so I finally hung the new one and topped it off. Now that I can see the coolant it’s constantly pumped full of bubbles. There is no oil in coolant or coolant in oil but I clearly have a bad head gasket. I had to walk away before I did any digging into the fuel system. I’m at the end of my rope with this thing.

Pulled myself together and went back to it. No more bubbles. Must’ve been air locked, but now there’s a bit of oil at the top. Not sure if it’s still maybe head gasket or if it’s environmental contamination. Giving up for now. Might try flushing the coolant system and looking closer at the turbo in a few days. Any suggestions on determining for sure if my head gasket is ok or not?

Keep checking the engine. But my 892E the pump regulator on the back cap was sticking. So if u bumped the hydraulics and got it unstuck, it had power, but when it got stuck it would just lug down and not really work. Ended up getting pump rebuilt (a year later the other one also). Local hyd guy got parts about 1/2 of Deere prices and now mine works well.

Are you referring to the main relief valve?

sounds familiar only there is no bumping it to make it work, just sucks all the time.

Did something change between your posts #1,3 and 4? it sounded like you had decent power sometimes. And now you have very low power all the time?

Ben Steiner said:

Are you referring to the main relief valve?

sounds familiar only there is no bumping it to make it work, just sucks all the time.

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no I am referring to on the head of the two hydraulic pumps. Mine may be slightly different as it’s an 892e with pilot valves, but thought the pump design was similar.

Once I finally had a bucket on it I dug 100’ of my ditch out and it is agony at all times. It will dig but always bogs the motor when lifting boom or stick or turning. Have to really baby it or let it recover if I pull too hard.
When I tried to lift the tracks it would not do it unless I move the stick also. Maybe just not enough power to lift and slide the bucket, not really sure.

Keep checking the engine, but there is a way to force the pumps to full power for testing (I wouldn’t run that way). But I’d have to look in to how to do it. It was either connecting a line, or disconnecting a line and it would full stroke the pumps.

Here is my pump setup. I’m foggy on theory of operation. What actually causes the swash plates to move up and down to vary the flow? My mechanic friend was only familiar with newer machines that are electronically controlled.

Ben Steiner said:

Here is my pump setup. I’m foggy on theory of operation. What actually causes the swash plates to move up and down to vary the flow? My mechanic friend was only familiar with newer machines that are electronically controlled.

Click to expand...

blue is what strokes the pump. The red, is the end cap that is what moves under that cap to stroke the pump. Do I have the books? I’ll see if I can find a few pages when I have more then my phone. I also think I have pics of it apart (but I’ll have to track that down).

Here is with the rear cover removed and the valve that slides back and forth.

So, in the second picture, that is called the swash plate, correct? And that is what was sticking in your pump causing a bogging motor and lack of hydraulic power?
Also, you’re saying there is a way to force it to full flow to tell if that is the problem I have going on? Just trying to make sure I understand correctly.

That is the mechanism that moves the swash plate. It is called a valve if I remember correctly. The upper pic with blue, has several metal lines attached is the govener or regulator that controls the valve. On mine, I believe removing and capping one of the steel lines, removes the feedback of the hydraulic pump and forces the pump to max flow. On mine, that valve and cap (the part removed), had some rough spots and would cause the machine to not have powe to dig, track, lift etc. one pump runs some functions and one track, the other runs other functions and the other track. We did gauges and testing but finding that the results weren’t consistent we’re the clue for us. But you also need to verify your engine is ok. FYI, someone had reset our rpm to 65% of normal on high. Because the hyd functioned better if it didn’t try and stroke the pumps.

Pulled the muffler today. Turbo looks good on both sides and spins free, doesn’t contact the sides. Still not sure why boost is so low. My gauge is questionable though and I used 15’ of 1/4” line. Kinda thinking the motor isn’t able to spin under load long enough to build full boost, maybe….

Also looked at the lift pump, pulled a small amount of debris out of it and blew air through the feed line. It primed much easier than before, almost instantly. Also observed the return fuel flow under load like the manual says, saw no change in flow and some, not excessive black smoke under heavy load. I am pretty confident the fuel system is not the culprit.

My coolant system still had pressure in it after days of sitting. I really can’t imagine that would be the case if I had a head gasket issue. I’ll keep an eye on coolant and oil for now. I do not have equipment to do a leak down test, will purchase if needed.

I’m feeling fairly confident in this motor as far as my limited abilities go and getting more confident that this is hydraulic in nature. Anyone have any further input on that or is it time to pull the pumps apart for a look?