We have an older Cat 318 Excavator that a pump problem just surfaced on the excavator. It happened suddenly & the pump chatters quite loud, case drain line pulsates (the one pointed at in the pic) & when testing the flow, the case drain line delivers a high quantity of oil when taken off & directed into a bucket to test the flow; about 1.6 liters in 8 sections at high idle. We are told that it likely indicates pump failure. Also, see the evidence of the brass slivers in the case drain filter (the white filter) when cut open. The pump seal has been leaking for quite some time, near where it couples to the drive dripping out of the vent hole. Anyone have any advise on what our next step should be? Unit has a little over 10,000 hours in it & we have owned it for about 2 years.
Send them out, or get an exchange set. Sounds like you've lost a retainer plate and/or some piston slipper feet. 10,000 is a decent life if that's the original pump set, they're due.
We decided to go with new pumps. They are ordered & should be here in a couple of days.
New pumps were installed yesterday & we ran the excavator for a few hours today.........everything seems good now. It was suggest that we pull the "case drain" filter that we replaced when the pumps were installed, after a few hours of operation, cut it apart & see how it looks inside, just to be sure, which we plan to do. We plan to do an oil sampling at the same time.
You'll need to pull/inspect/change filters on a regular basis for the short term to make sure that anything generated by the previous failure has been caught. When you have oil samples done make sure the analysis includes a particle count, aka ISO Cleanliness Code. The target for your machine hydraulic system should be a maximum 18/15 and preferably less.
Ok, thanks for the additional information Nige. Any idea at what intervals the filters should be pulled off at & inspected?
I'd be doing it every 50 hours or less if I had invested the amount of money on new pumps that you have. Also ask your dealer if there are any High Efficiency cleanout filters available for your machine that can be used to ensure that any remaining circulating particles are removed as fast as possible. Here's a little more information on ISO Codes .... http://www.machinerylubrication.com/Read/28979/iso-cleanliness-code
This is the evidence that we found with the pump closest to the engine, that we took apart, just to see what went wrong. Is there any point in keeping any parts from old pump assembly, or just recycle everything?
That pump could most probably be rebuilt despite the visible damage, the question is whether or not it would be economical to do it.
For sure got your money's worth out of it with that many hours. Yes it has value, as Nige says it could be rebuilt so you may be able to sell it to a pump rebuilder or someone looking for a good core. That's one of the cleanest pump failures I've ever seen, usually they grenade completely. Would have pretty quick if you'd kept running it!
Basically all the damage to the faces of the slippers was caused by the one that split right down the middle. It reminds me of a quote from a Cat training course I went to one time many years ago about component life estimating. "The optimum life of an engine (or any other component for that matter) is one revoultion of the crankshaft before it fails......" I think that pump qualifies in spades.
Sounds like your instructor knew the guy who taught the "Failure Analysis" class I took many years back. He also worked building racing engines for some motorcycle racing team. His goal in building engines was to have them fail on the "Victory Lap" said if they lasted any longer they were over-built and wasting needed horsepower!