Cat oil analysis opinions

[Columbo]

I have attached the latest oil sample report for my excavator, a Cat 311B 8HR00401. An oil sample was completed when I bought the machine, most of the fluids indicated extended service intervals, etc. As suggested I completed a second oil analysis after 100 hrs, that report is attached. Overall, all of the samples showed improvement. The one that I’m curious about, and would like opinions on, are the two final drives. One final drive shows normal wear metal counts and particle counts. The other is still showing elevated wear metal in the sample. What, if any, action should I take for this specific final drive at this time? Thanks!

 

[Nige]

What did the condition of the mag plugs look like on both finals when you sampled the oil most recently.? Any distinguishable difference between the two.?

The RH final drive was much more contaminated that the LH one at the previous sample. It stands to reason it might take more cleaning up. Despite that the iron & silicon contents have reduced by a factor of 10 from what they were previously.

FWIW I would get the machine up to operating temperature, drain the oil from that final drive, then refill it with the same quantity of diesel. Lift the track off the ground and run it for 5 minutes in each direction - or longer depending on your levels of patience. Drain the diesel and inspect for metal particles by swishing a magnet around in it. Once the final drive has completely drained, refill with fresh oil, go another 100 hours, and resample.

Is it leaking any oil at all from the Duo-Cone seal.?
It might pay you to inspect the area of that seal (not easy to do) and do a bit of cleaning. Do NOT pressure wash it. Doing that that can drive dirt in between the steel rings of the seal and lead to their destruction in short order.

 

[Columbo]

Thanks, Nige. No significant metal noted on the magnetic plugs. No oil leakage at all from the duo cone seals. I had flushed both finals with diesel at the last oil change, I can do that again on this final drive and resample. Thanks for the suggestions!

 

[Nige]

I didn't bother going back to check but I thought the "diesel flush" option had been discussed before.
Sometimes it takes more than one flush..........

 

[Columbo]

Yeah I’ll do it again, it’s a simple, low cost solution! Hopefully another flush and fill will clean this drive out to match the other. I’ll take another sample after 100 hrs.

 

[CM1995]

It's always nice to see the red and yellow turn into green on a most recent sample.

 

[Bluox]

You know I've been doing this type of work for a number of years and I 've never seen diesel rebuild a wore out anything.
Bad Bob

 

[Columbo]

You know I've been doing this type of work for a number of years and I 've never seen diesel rebuild a wore out anything.
Bad Bob

Well, that’s why I was asking for opinions. This is a low-use machine but I’d rather prevent a catastrophic failure then take my chances and pay more when it fails. That said, a diesel flush and oil change cleaned up the other final to an acceptable level so maybe this one just needs another clean out? What would you suggest as a course of action given these samples? Thank you!

 

[willie59]

You know I've been doing this type of work for a number of years and I 've never seen diesel rebuild a wore out anything.
Bad Bob

Not once did anyone suggest diesel will rebuild anything, you're missing the point entirely. What is being suggested is cleaning the innards of the final and then fill with fresh oil, then see if metal keeps appearing in upcoming samples. If it does, pretty good indication something is going on in there.

 

[Delmer]

The oil sample is measuring iron at an atomic level, hopefully the chunks of metal stuck to the magnet. If the chunks on the magnet showed catastrophic damage, then you've got a higher probability of failure in shorter hours. If the oil had many thousands of hours on it to get alarming iron levels, that's different, and flushing the oil and continuing to sample might get you a clean oil sample, and a reasonable expectation that the drive will be reliable.

 

[CM1995]

Not once did anyone suggest diesel will rebuild anything, you're missing the point entirely. What is being suggested is cleaning the innards of the final and then fill with fresh oil, then see if metal keeps appearing in upcoming samples. If it does, pretty good indication something is going on in there.

^^^ Exactly Wille.

 

[Columbo]

So, update from this weekend. I drained the oil from this final drive (had maybe 5 hours on it, tops) and certainly saw glitter in the oil. Flushed with diesel as suggested and refilled with fresh oil. One thing I confirmed was that the oil drain/fill plugs are not magnetic. I have a new spare plug from cat and that one is not magnetic either. Was there an update or model change when cat switched magnetic plugs? Any thoughts on what to do from here? As it’s a machine I use sporadically for my own projects who knows how long this final may last. If I run it to failure does that negatively impact the cost of a rebuild versus repairing it now?

 

[Nige]

That's surprising, and there isn't a magnetic version of a plug the same size available anywhere either.
All I can suggest is to remove the cover and see if there is enough space for a thin rare earth magnet to fit so that it will not get hit by the gears and planetary carrier ads the FD turns. Maybe you could even install a small RE magnet on the end of the plug.? there are three of them so 3 small magnets might just do the job.

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