This post is about "broken" hydraulic pumps that aren't broken. Yes,
there is that kind of pumps, and every once in a while one of these
crashes at our workshop, making me wonder what the hell it's doing
here... As I have already mentioned before, my main craft is hydraulic
pump and motor repair. I like doing it, I've been doing it for a long
time and even dare say that I am "relatively" good at it, so you can
take my word for it when I say that NOT ALL "broken" hydraulic pumps
and motors, brought to a workshop to be repaired, ARE REALLY
broken!
This may sound a little extreme, but it is
true, and this sad fact is well known by all hydraulic workshop owners
and workers, who will also confirm you that in 99 cases out of 100 the
reason for it is inadequate troubleshooting
(the term "inadequate" in this context standing for "incompetent",
"hunch-based" and "tradition-based"). From what I've seen so far, these
"broken not broken" pumps and motors can be divided into:
1. "Broken" units that aren't broken at all, and
present no damage beyond normal wear, with the malfunction being caused
by something else (with the most ludicrous cause being a disconnected wire...).
2. "Broken" units, that aren't broken at all, but need adjustments.
3. "Broken" units, that are malfunctioning, but the
malfunction could be easily repaired without dismounting the
pump from the machine (like a clogged orifice, for example)
Every time when such an "excessive overhaul"
happens, thousands of euros get spent without any particular need for
that. One could argue endlessly about the commercial side of the
question, stating that, since workshops find themselves at the
receiving end of the money path, these situations shouldn't be
considered as something bad, and I can relate to that. But being an
industrial junkie, I will always defend technical side over the
commercial, and this is why I, for the millionths time, will repeat
something I say almost every day to people seeking troubleshooting
advice:
Never dismount a pump or a motor without confirming its malfunction and making sure it can't be fixed on the spot!
Efficient troubleshooting is a logical and systematic
search for the source of the problem. Hunch-based troubleshooting, on
the contrary, is another form of witchcraft, which is fun to watch and
occasionally delivers astonishing results, but when applied on a
regular basis is a direct road to bankruptcy.
Logical and systematic means that:
a) you must know and understand how the hydraulic
circuit in question works to be able to elaborate theories, and
b) you must confirm your theories through tests.
"Blind" overhaul of the main pump every time a
hydraulic equipment goes slow is just like removing a person's appendix
without any physical examination every time an abdominal pain is
present!
You wouldn't believe me if I told you how many times
I am asked to repair (often urgently) perfectly functional units! And,
despite all I just said, I know for sure that I will be asked that
again and again... There's a conviction in my heart, however, that IH readers will never be the ones responsible for this.
