PS Magazine - TB 43-PS-561
PS, The Preventative Maintenance Monthly
ISSUE 561
AUGUST 1999
Dear Half-Mast,
Our unit has wheeled construction equipment like the 130G grader,
MW24C scoop loader and 621B scraper.
Does it matter which direction the tires are mounted on these
vehicles?
SFC W.M.
perators, there are good reasons why your scraper’s TM 5-3805-248-14&P-1
tells you to check the hydraulic oil with the scraper idling and the cylinders
retracted. Checking oil that way saves seals and the hydraulic reservoir’s sight
glass, by making sure you don’t overfill the reservoir.
Why idling? Oil expands as it warms up. Warm oil registers a little higher on
the gauge than cold oil.
OK, but why retract cylinders? Oil used to extend the cylinders isn’t in the
reservoir to be measured. It’s in the cylinders doing its job. If you measure the
tank with the cylinders extended, it looks low.
If you overfill the tank for either reason, pressure builds
up—blowing seals. Too much oil has even been known
to blow out the hydraulic reservoir’s sight glass.
So, before you add oil, make sure the scraper is in the
parked position and all cylinders are retracted. Let the
scraper warm up a few minutes. The hydraulic oil level
should show between the ADD and FULL marks.
If you overfill the reservoir, remove the excess with an
AOAP vampire pump.
Construction Equipment . . .
Dear Sergeant W.M.,
Tactical vehicles, like HEMTTs and M939-series trucks, use a non-directional
tire. That means the tire can be mounted any way you want.
But, with the large tires on construction equipment, it’s a different story.
Those tires are designed for off-road use in loose sand, dirt, mud and gravel.
When pointed in the right
direction, the driving tires’ chevron
pattern provides the traction the
vehicles need.
If you’re not sure which way the
tire mounts, look at the direction
arrow on the tire’s sidewall. It
shows you the way.
Tires on non-driving wheels can
be mounted either way.
621B Scraper . . .
Oil level should
be between ADD
and FULL
Note tire rotation arrow
for
each
vehicle's
driving wheels-
-
yes, it
does
matter
!
don't forget
to
retract
my
cylinders
this
time!
right, i
don't want you
to
blow
another
seal
.
PS 561
23
AUG 99
PS 561
22
AUG 99
Back to Top Back to Top
