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[QUOTE=richwaugh;179367] JOhn,I would suggest that you open up the pressure relief valve on the loader controls and clean it out.If that PRV sticks open you'll have complete bypass and no pressure to operate the loader.It does happen.Just watch carefully when you disassemble the PRV so0 you don't lose any parts or get them in the wrong order - a digital camera can be a lifesaver here.The valve has a spring in it, so take it apart slowly and carefully so it doesn't go "sproing!" and send parts flying all over. [/QUOTE]

AHA!! A place where there could be a single point
failure if it got jammed with a piece of crud. Gosh,
Rich, if you keep this up, you might cure a small
part of my ignorance...........Maybe.

So I just tried to find my documents that might have
a parts "exploded view" of the controller and came up
empty. Does anyone have a web link to a page that shows
that? I am suspecting that the relief valve must be
under the round cap (on top) that seems to be made to
be removed with a Hex Key wrench....?...
Directly beneath (on the bottom) the round cap is a
pipe that is capped off. Probably related........

Thanks again for all the help,
johnD

PS That "sproing" sound is the 2nd worst sound I would
want to hear. The worst is "OOPS" from a Doctor
doing surgery on my bod!

Jinma 224 Loader does not lift or tilt
Jinma Farmpro Agracat Nortrac
Replies 23 Post by dnaraG_1M

Murf:
Ah, I think that we were on different tracks. You
are describing localized boiling that creates bubbles.
That had not occurred to me in the context of cavitation.
It does seem reasonable to me that a surfactant which
lowered surface tension - better wetting - would lower
the thermal resistance at the coolant / metal interface.
If lowered enough, perhaps the heat would flow into
the coolant mass fast enough to prevent a localized
boiling. Intriguing concept. I wonder if my wife will
let me use a pan for an experiment..!...

I was on a different track. Having grown up around boats,
I have always thought of cavitation as a purely mechanical
effect. Don't think that those props get all that hot.
It had been my understanding that the damage occurred
when the bubbles were smashed, dislodging tiny bits of
the metal prop, sleeve, or whatever..... Can you
describe what part of the thermal effect causes the damage?
Is it still the smashing of the bubbles or something
else entirely?

Which would be the predominating effect - thermal or
mechanical?

So much to learn, so little time!
johnd

Best way to keep cool SCA OAT HOAT
Jinma Farmpro Agracat Nortrac
Replies 12 Post by dnaraG_1M

>As I stated before, the steering wheel provides directional
> input to the steering controller. Physically turning the
>wheel activates the steering controller, which in turn
>tells the PV that it requires fluid from the primary
>circuit. The PV opens, permitting fluid to enter the
>secondary circuit. The PV then routes this fluid to the
>controller which passes it on to the steering cylinder
>(and ultimately back into the primary circuit). Remove
>steering wheel input, there's no steering controller
>intervention, the PV closes.
Yes, that's what I had understood from my previous reading
of your, and other's, postings. Putting it in my own
words, I understand that to say that "if the pump is
running, the steering controller directs the pump's
pressure to the slave cylinder - but does not generate
it's own pressure to the cylinder".

I hope that's right.

But in your previous reply, you addressed what happens
when the pump is NOT RUNNING. In that case, you were
very clear that the steering controller CREATES it's
own pressure from steering wheel motion. From
combining these two concepts, I conclude that the
steering controller operates in two different
ways, depending on pump working/not working.

IE
1) Pump running -> the steering controller DIRECTS
the pressure from the pump to the cylinder.
2) Pump not running -> the steering controller CREATES
pressure on the cylinder. Pressure which can/does
damage the seals in the cylinder.

Boy, that sure was non-obvious to me at first. But then,
I really have no idea of the internal implementation of
the steering controller and, being a simplistic guy, was
assuming a simplistic valve setup. Those mechanical
engineers are just way too sneaky for me....(grin)..

cheers,
johnd

Hydraulic steering problem Jinma 284
Jinma Farmpro Agracat Nortrac
Replies 18 Post by dnaraG_1M