Cat 246 - Loss of Power

[01Time]

S/N 5SZ0xxxx

While clearing cedar trees on my property, for no apparent reason I suffered significant power power loss (drive system, the hydraulic system maintained full power). I then noticed a kind of a whine noise coming from the motor. It seems to be loudest on the left side, kind of near the air filter.

No pop, bang, or puff of smoke. But, it barely creeps on flat ground and won't move under full throttle on any sort of incline.

I did recently refuel, so I suppose it might be fuel related? Would that also explain the sound?

Here are a couple of videos so you can see what I am trying to explain:

Video 1: Trying to move

Video 2: Sound coming from engine area

 

[Steve Frazier]

Based on what I hear it doesn't sound like your engine rpm is dropping. The whine I hear sounds like the hydraulic pump, not fuel related. Have you checked the hydraulic oil level? There's a sight glass on the right boom tower.

 

[01Time]

Based on what I hear it doesn't sound like your engine rpm is dropping. The whine I hear sounds like the hydraulic pump, not fuel related. Have you checked the hydraulic oil level? There's a sight glass on the right boom tower.

I'll verify when I go back out there tomorrow, but it was sitting right in the middle when I checked it before I started using it.

From what your saying, I'm thinking this might be related to an issue I created for myself a couple months back when I dropped some tubing into the hydraulic tank.

Is it a good chance that the tubing is causing a blockage and worth draining the fluid and pulling out the hydraulic tank to remove the rogue tubing?

 

[Steve Frazier]

It could very well be that the tubing worked its way to the pickup tube to the pump and got sucked in. Have you tried the machine again since you reported this? It's possible that when shutting the machine down the tube would dislodge and you'll have full hydraulic power until it becomes stuck again. IF you haven't damaged the pump. If you find this is the case I bet you've found your problem.

 

[01Time]

It could very well be that the tubing worked its way to the pickup tube to the pump and got sucked in. Have you tried the machine again since you reported this? It's possible that when shutting the machine down the tube would dislodge and you'll have full hydraulic power until it becomes stuck again. IF you haven't damaged the pump. If you find this is the case I bet you've found your problem.

I did start it up again after letting it sit for a while, and it was the same.

Hopefully this isn't too complicated and I can get it done tomorrow. My machine is an 1.5 hour drive from my house, so I hope I bring all the tools I'll need!

Thank you for the help. I'll follow up when I can get it done to hopefully provide a resolution.

 

[ThreeCW]

A bit of brain storming here.

Possible problem with your pilot valve (stick drive)? Is the problem only when going straight ahead? How does it react if you turn left or right. How does it react when reversing up the same grade?

Possible final drive problem??

Have a look at this recent thread with a final drive problem and perhaps do a search of "final drive failures".

https://www.heavyequipmentforums.com/threads/cat-277b-boom-hydraulics-work-fine-not-moving.83739/

Hopefully it is a just a plugged suction causing your problem ... as replacing a final drive will be a costly repair.

 

[01Time]

A bit of brain storming here.

Possible problem with your pilot valve (stick drive)? Is the problem only when going straight ahead? How does it react if you turn left or right. How does it react when reversing up the same grade?

Possible final drive problem??

Have a look at this recent thread with a final drive problem and perhaps do a search of "final drive failures".

https://www.heavyequipmentforums.com/threads/cat-277b-boom-hydraulics-work-fine-not-moving.83739/

Hopefully it is a just a plugged suction causing your problem ... as replacing a final drive will be a costly repair.

That does sound similar to what I'm experiencing. For some reason I thought only tracked machines had a final drive? I'm probably wrong as I'm learning as I go...

I don't have much power in any direction, except when gravity is helping out.

I just got out to my property so I'm going to pull the hydraulic tank and remove that tubing - it should be removed anyway. I'm really hoping that fixes the problem because if it's anything else it's probably going to be very expensive.

 

[01Time]

Just getting out here to work on this and here's what I'm seeing so far...

The sight glass read over MAX when I got here. I moved it to the shade to work on it and now I'm noticing the bucket being equally sluggish. After I ran it long enough to get under a tree, the sight glass is now showing between MIN and the bottom of the gauge.

I've got the ROPS up and I'm looking for the drain line. I guess the shade is too effective, because it's hard to see into the open bay and I can't seem to find it. I might just have to put it back in the sun just so I can see what I’m doing. (I guess the human eye doesn’t like such a divergence in lighting!). Plus, I don't think the drain pan I brought is going to fit underneath. I might need to use some southern ingenuity to figure this out.

 

[01Time]

Got the tank out and I found the tubing I dropped in there. I also found a piece of cut water hose that I assume ended up in there the same way as my tubing did from the previous owner. But, I also found the tank filter floating about in the tank, not screwed into the tube it's supposed to be. And that leads me to what this has all caused.

The rogue tubing got sucked in, since there was no filter attached to stop it and it got all the way to, what I'm assuming is the pump. Below is a photo of the tubing inside the tube.

I'm taking everything I pulled out home so I can make sure it's cleaned out. Besides that, is there anything else I should do before I put it all back together and fill it back up with fluid?

 

[ThreeCW]

Hopefully you caught the problem in time before any damage was done. Not sure what damage could be caused to the hydraulic pump by starving it from fluid. I wonder if cavitation induced damage is possible? It is concerning that initially only the drive system was affected and the other hydraulics were not, and then later the other hydraulics were affected. Perhaps it was because the drives system requires a lot more flow rate than the other hydraulics and the plugging was only partial at that time.

I would suggest running it after assembly to test if everything is back to full functionality. After you have circulated the hydraulic system well, I would suggest changing out the hydraulic oil filter. I also suggest to cut the old filter apart and see if any tell tale damage (i.e. metal particles) have collected in the filter pleats.

 

[01Time]

Hopefully you caught the problem in time before any damage was done. Not sure what damage could be caused to the hydraulic pump by starving it from fluid. I wonder if cavitation induced damage is possible? It is concerning that initially only the drive system was affected and the other hydraulics were not, and then later the other hydraulics were affected. Perhaps it was because the drives system requires a lot more flow rate than the other hydraulics and the plugging was only partial at that time.

I would suggest running it after assembly to test if everything is back to full functionality. After you have circulated the hydraulic system well, I would suggest changing out the hydraulic oil filter. I also suggest to cut the old filter apart and see if any tell tale damage (i.e. metal particles) have collected in the filter pleats.

I'm really hoping that since it wasn't being ran completely dry, just obstructed, it's just a matter of removing the obstruction to get it back going again.

After further thought, there was an impact on the boom hydraulics from the beginning. When I initially encountered this problem, I put the machine in high throttle so I could move it to a spot I could look at it. And that is when I made the initial assessment of the bucket operating normally. But as I further evaluated everything, the movement of the boom only operated normally at high throttle. It’s likely as you said, that the hydraulic force necessary to operate the boom is much less than what it requires to propel the machine. So, it was affected - but just at a lesser extent.

Assuming I can get out to my property later today, I’m hoping to have everything put back on and tested by the evening. If not, I might not have resolution until the weekend.

 

[Steve Frazier]

Assuming you didn't run in that state for very long it shouldn't have caused too much damage. I think the biggest concern would be the pump overheating as the oil passing through the pump also cools it. If it got hot while starved for oil it could cause the pump to score itself.

As a rule, anytime a machine sound changes from the norm you should shut down asap and determine what has caused it to happen.

 

[01Time]

Assuming you didn't run in that state for very long it shouldn't have caused too much damage. I think the biggest concern would be the pump overheating as the oil passing through the pump also cools it. If it got hot while starved for oil it could cause the pump to score itself.

As a rule, anytime a machine sound changes from the norm you should shut down asap and determine what has caused it to happen.

I may have permanent damage to the system or there's something else going on. I put it back together yesterday and it didn't improve.

I think I'm going to have to punish my bank account for my errors and have a mechanic come out to fix it. I'll report back when I get an answer so that it may be helpful to others.

 

[Steve Frazier]

I hope it's not catastrophic. Good luck!!

 

[01Time]

I hope it's not catastrophic. Good luck!!

Thank you, me too! I had a guy come out to look at it today and he seems to think there is debris in the hydraulic control valve which is keeping some of the valves open resulting in a loss of pressure. He's supposed to take it apart, inspect it, and clean it out tomorrow. Fingers crossed, because if that is all this is my bill will stay in the three digits.

 

[ThreeCW]

Here is a recent thread that I think you should read ... it may help in your trouble shooting.
https://www.heavyequipmentforums.co...ith-hydraulics-machine-moves-very-slow.80965/

And some more bed time reading ... you might be able to get a few more trouble shooting tips here:
https://www.heavyequipmentforums.com/threads/2006-cat-287b-no-hydraulics.80858/

 

[01Time]

Here is a recent thread that I think you should read ... it may help in your trouble shooting.
https://www.heavyequipmentforums.co...ith-hydraulics-machine-moves-very-slow.80965/

And some more bed time reading ... you might be able to get a few more trouble shooting tips here:
https://www.heavyequipmentforums.com/threads/2006-cat-287b-no-hydraulics.80858/

Thanks. Unfortunately, those symptoms do sound familiar. I'm really crossing my fingers it's just a bad relief valve.

 

[ThreeCW]

As per those threads, cutting open your hydraulic fluid filter and checking for solids (if any) is key to analyzing your problems at this stage. If no solids are found, that would be a very good thing.

 

[01Time]

As per those threads, cutting open your hydraulic fluid filter and checking for solids (if any) is key to analyzing your problems at this stage. If no solids are found, that would be a very good thing.

I’m heading out to my property now to grab the filter.

 

[ThreeCW]

Found the following on:
https://www.hydraulicspneumatics.com/technologies/hydraulic-filters/article/21882556/filtration-tips-you-may-not-know

"Check used filter elements for trapped metal. An increase in yellow metal shows a failure in wear plates or slippers. An increase in white and gray metals (ferrous) indicate wear caused from contamination or cavitation. Black, carbonaceous material, sticky gooey varnish, or gray ash may signal time for an oil change and a review to see what is causing the heat."