Catastrophic Failure...is truly as bad as it sounds.

I had never tackled a pump failure on a backhoe before. Now I'm on my third one this summer. I always understood the concept, but the reality is so much worse. Literally, the metal gets almost everywhere. Every cylinder has traces of metal, the tank, the oil cooler, lines, valves, cartridges. I'm doing these under warranty, so I don't need to take any shortcuts. I'm averaging about 120 hours of laboron each one. The really diabolical part is that you can flush out 3 or 4 hoses in a row and not find anything, then you flush hose #5 and the sparkles just pour out of it. Same with the valve sections in the backhoe valve. Another tech said, "don't worry about the outrigger cylinders, The hold valves will catch anything going that way."
Nope,.. not true. Just as much metal in the outriggers.
I don't really have a point, I'm just sayin' Holy Cow!! it's really bad. If you ever encounter this, plan for the worst. Don't trick yourself into thinking, "well, I doubt anything got into _________ part of the system." it did.

And even after a complete tear down and washing I would not be surprised to find flecks showing up in filters or on oil samples. I hope that you are replacing the coolers. There are too many hiding places in them for me to feel comfortable about flushing and reusing.

It's kinda in the name.
Glad to see you're doing right by your customers

Where’s the kidney-loop machine when you really need it.? That puts the final cherry on top of the cake after you’ve sweat blood & bust knuckles pulling the system apart. Because if you don’t, there’s always going to be some particles left somewhere to trash the replacement pump.

I hate contamination failures. They are the stuff nightmares come from.

Logger using a filter cart:

I have had the pleasure of one cleanout so far in my career. It was on a landfill loader. It was terrible. Cleaned out all the lines, replaced all valve cartridges, flushed out valve bores, cleaned out tank, replaced cooler, replaced all pumps and motors, rebuilt all cylinders, filter carted it once all back together...took forever. I was sick of that never ending job

I've never encountered a catastrophic pump failure (yet), but I have always wondered, at least in theory..... if you replace the pump and filter, clean the tank and add new hydraulic, then start it up and run it without touching any control valve....then doesn't the pick up screen protect the pump which is not under load...and doesn't the return filter prevent particles from re-entering the hydraulic reservoir? Then if you gently operate each control valve being careful not to permit any cylinders come to their full travel, won't the filter catch any particles in them? I imagine you would have to replace the hyd filter several times while doing this. I have never tried this, just wanted to discuss in theory.

When i worked at a demo company they had a cat backhoe forget the model now that had a major failure there cure after doing whatever they did was a huge ass magnet stuck to the hyd tank , it was done way before my time , they took the magnet off one time and drained the tank and cleaned it out i was told thinking it would be ok, it wasnt magnet had to stay on it or stuff didnt work or would get stuck, i thinken they didnt even attempt to flush it out good thing it was a yard machine at that point .

I just went through that myself on an IMT that puked a rotary drive motor. Thankfully it was caught quickly and they designed the system with a large filter to catch anything rotary related before it made it to the pumps. We ran the oil through a filter cart and swabbed hoses.

In my experience, the degree of clean out was dependent on what type of machine and hydraulic system you have including the materials used in the components. Wheel loaders that use aluminum bodied gear pumps seem to work out fine with draining the tanks, changing filters and maybe flushing the valves. Units with vane pumps usually made a bit more mess as the broken vanes seemed to shatter like glass and end up in everything.
Hydraulic excavators that use mostly brass in the pump and motor barrels and for the slipper feet also seem to survive a little better. Excavators that use lots of steel and use very complicated control schemes are the worst. I saw plenty of Link-Belts with $60K bills for new pumps and clean outs. I saw at least the same number of Komatsu excavators with just the cost of the pumps and filters.
Planned maintenance is the way to prevent those catastrophes. Keeping fluids clean and changing out components before failure is worth every penny.

Back in the late 90's,we had a Link-Belt. 5800 I think.
I don't know if it was a link-belt fix or a dealer fix but they mounted 2 high pressure filters right off the pumps. Too long ago to remember what pump they were running in them but had a history of exploding and polluting the system. They also had an extra filter in the case drain from the pumps.

Changed on a 500 hour service.
Pain in the you know what.
They were a big Fairey Arlon filter, with that thick heavy canister to withstand the pressure. Since they were mounted right in the out line from the pump, they just bled oil when changing. It would run down the filter and make just about impossible to hold onto, let alone start it in those super fine threads. I stuck a piece of traction tape onto the side of the filter housing so at least I could hold on to it.

When the pump let go, as they knew it would, the shrapnel was all contained.
The fact that we had an exceptional operator on it helped. As soon as he felt the pump let go, he would shut the machine down, none of this try to keep it going routine.

The company I retired from used to have a fleet of Kobelco machines. Older models. They survived a pump failure with minimal clean up.
I would use the filter cart to pump out the tank. Hockey stick with rags on it to wipe the bottom of the tank. Replace all hyd filter and use the filter cart to pump the oil back in.

But that was logging. Slam it together and get it back to work.

I was working for the Link-Belt dealer back in those days. LS4300CII were the machines in the woods back then and they had a habit of doing just that. We put together a kit package with the high pressure filters for those machines which ran around $3,500 installed. Weyerhaeuser Raymond put one on a brand new machine and they had an older machine without. The older machine pumps went and that was the $60,000 bill for the clean out. The new machine pumps went at about 5,000 hours and all the stuff ended up at the filters. New pump and filters and back to work.

There was a problem with the high pressure filters though in that the mounting bodies were made of cast steel and they could only take so many spikes before the cases would crack and start leaking. That happened at around 6,000 hours. The white hats at the lazy W always beat us up about that. Before I left the dealer I got short timers attitude and told one of the white hats that he should learn how to do basic arithmetic. I don't think that to this day they have any idea of the life cycle costs of their machines.

I'm using these foam "pigs" to flush the lines, here's a shot of debris I found in the Ride Control block. I'm sure if this wasn't a warranty, I'd be cutting more corners. I know I've had boss's who would just want a magnet and a few filter changes. But I can submit all my time, so I might as well get in there.....In the Ride Control?! seriously?!

That's the same tool and sponges that we use on all our hydraulic hoses after assembly.
You can bet your bottom dollar that anywhere oil flows in the system, particles will be there …….

Same system I bought when the IMT threw a fit. Spendy but it sure is fun to shoot those pigs out!

Muffler Bearing said:

View attachment 201486 View attachment 201487 I'm using these foam "pigs" to flush the lines, here's a shot of debris I found in the Ride Control block. I'm sure if this wasn't a warranty, I'd be cutting more corners. I know I've had boss's who would just want a magnet and a few filter changes. But I can submit all my time, so I might as well get in there.....In the Ride Control?! seriously?!

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well its on the plus side of the boom cylinders, I can see that. I would be most concerned with orbitrol steering valves, PWM valves and all those little orifice fittings. Honestly don't think I'd have considered the ride control valve, What about the accumulator?

I'm replacing R/C accumulator, and the pilot control manifold and its accumulator. Also any cartridges. I'm not sure about steering stuff yet.

Junkyard said:

it sure is fun to shoot those pigs out!

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definitely!