[Vwdiesel] Risks of Hydraulic Heating?

[James Hansen]

Don't discount that your hydraulic oil may be too heavy for the temperature,
all it needs to be is 20W for summer and winter.  The crystallizing thing in
the filter just sounds like really cold heavy weight oil too.  It gets to
looking sort of crystally when heavy oil gets cold, just before it starts to
simulate grease.

Lee's suggestion of a warming circuit is very valid if the system can pump
the oil around that is.  If it can't, you should just use thinner oil.  I
use donax td, summer, winter, gear cases, hydraulics, transmissions, etc.  I
use an older case 2860 tractor on a grain vac in winter.  Trouble is, it's
powershift (farmer speak for semi-auto transmission) and the hydraulics,
rear end, and transmission are a common gearcase, with a barrel of oil in
it.  It takes two hours of idling to warm it enough to just drive, not use.
(use it when it's cold, the oil pressure spikes kill the clutch packs in the
trannny)  I have a hydraulic hose roughly three feet long, with an end to
plug into the tractor hydraulic circuit on both ends.  Plug it in, pull the
hydraulic lever, and let it circulate for half and hour with the engine at
idle, and it's ready to go at any outside temp.
-James

-----Original Message-----
From: vwdiesel-bounces at vwfans.com [mailto:vwdiesel-bounces at vwfans.com]On
Behalf Of Val Christian
Sent: Tuesday, December 20, 2005 7:18 PM
To: vwdiesel at vwfans.com
Subject: [Vwdiesel] Risks of Hydraulic Heating?


Gang,

On my DIESEL (idi, even) tractor, I have an annual problem with hydraulics
jambing up.  What I think happens is that moisture in the hydraulic system
(transmission, brakes, loader, etc.) crystalizes at low temps, and as a
solid, clogs the hydraulic filter.

Heating the filter, with a propane torch frees things up, and after a
period of operation at winter temps, the system seems pretty trouble free.

Here's the problem...how to cook out the oil?

This year, I'm considering running the tractor at a moderate power
1800 out of 3000 RPM, and putting the hydraulics into a lock mode, so that
the pressure limiter goes into bypass.  I'm a little concerned about
the effects on the bypass valve (erosion, etc.), and local heating of the
hydraulic oil as it goes through the bypass.  Can anyone comment?

Val

ps: As the battery fails on the tractor, I find that running the block
heater
pays of (timewise, not powerwise) over topping the charge on the battery.
Hello summer cylinders.  If my cars were harder starting, I'd be popping
frost plugs.

pps: Extreme cold starting technique...I've seen the gas/kero soaked rag
trick used at the quarries.  I did something similar on an old Rabbit,
except that it was in the garage.  I wanted something cleaner.  I pulled
off the crankcase vent hose, and used tissue saturated with isopropyl
alcohol.  I reasoned that the tissue wouldn't hurt the engine when injected
and the alcohol wouldn't be as sooty.  Later refinements had an assistant
holding a propane torch in the intake manifold.  Preheating the propane
in extreme cold helps, but the burn is short.  5 or 10 seconds.
The same torch is used to blast misquitoes in the garage in the summer.


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