hydraulics

shugy368 · Post by **shugy368** » Sat Jul 30, 2016 2:45 pm

Hi everyone, good day to you all, I am experiencing a slow lowering of my loader when raised and engine off. could a low fluids level cause this or am I looking for a bad seal? Can't see fluid dripping any where, maybe internal ?

Also my service manual says when changing same fluid to replace with S.A.E 5W- 20 oil, not hydraulic fluid? Is this correct or a misprint in my manual?

Stan Disbrow · Post by **Stan Disbrow** » Sat Jul 30, 2016 3:37 pm

Hi,

If you can't see a leak, probably seeping back thru the control valve. Your manual is printed correctly for when it was new. These days, use a decent hydraulic oil. They have additives which you want, which didn't exist back then.

Stan

pop pop · Post by **pop pop** » Sat Jul 30, 2016 4:07 pm

hey shugy, i figured you'd be busy fighting fire,,that guy Scott is a fireman down there..he is just on the south edge of it.(or was)
to answer your question, one of your spool valves probably needs to be pulled, it may just have slug/debris in the spool.
very easily checked. you may notice an o-ring or 2 needing replaced.
figure out which lever lowers it and pull out that spool.
of course engine off with no pressures.

shugy368 · Post by **shugy368** » Sat Jul 30, 2016 6:48 pm

thanks Stan I was a little confused by that, and pop pop I don't see any reference to a " spool " in my service manual. Can you clarify a little more? Thanks. and I am not a fireman but my son rides along in the cal fire helo as a paramedic.

jtrichard · Post by **jtrichard** » Sat Jul 30, 2016 9:08 pm

Most likely the piston cups are leaking by .... Since your book says OIL I have to assume we are talking 440 or before?...... A spool is the rod/shaft/piston in your control valve they CAN wear and leak by but I would lean more the piston seal in the lift cylinders

Stan Disbrow · Post by **Stan Disbrow** » Sun Jul 31, 2016 5:13 am

Hi,

The control valve pistons look a lot like thread spools, which is where I think they got their name from.

On the earlier machines, they have adjustable rods between the valve pistons and the lever. So the issue may well be with that. You could tell by just how much lever action is needed before it drops.

And, yes, it might be the piston seals in the cylinder(s). You didn't say which machine and blade, so you might have only one....

Stan

shugy368 · Post by **shugy368** » Sun Jul 31, 2016 9:59 am

Once again I asked for the ingredients without letting you all know the main dish

I have 1956 JD- L 420-C with a Hydreco monoblock double valve which operates the four rams needed for the loader

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