PS Magazine - TB 43-PS-679
PS, The Preventative Maintenance Monthly
ISSUE 679
JUNE 2009
10
PS 679
JUN 09
11
PS 679
JUN 09
Without the mounts, every bump during operation makes the cab rock and bounce.
And when you raise or lower the cab, it can tilt, putting extra stress on the hydraulic
struts. The problems are even worse if your truck has add-on armor.
If you notice cracks, tell your mechanic. New rubber mounts can save you a lot
bigger repair bill later.
Test with Bed Flat
Make sure the dump bed is completely lowered before you check the fluid level in
the hydraulic reservoir.
When the bed’s up, the fluid is in the lift cylinders. You won’t get a true reading of
the amount in the reservoir. Adding fluid with the bed up can blow seals when the bed
comes down.
While reconnecting the line, be sure not to cross
thread the Ftting. If you strip the threads, the truck will
have to go to support to get the hose replaced.
ReFll the tank and check the line for leaks. If it’s
leaking, tighten the Ftting
1
/
6
turn or one flat at a time
until the leak stops.
Since
there’s
no
drain
plug, disconnect the oil line
at the bottom of the tank.
Make sure you let the oil cool
before you loosen the line, so
you won’t get a hot oil bath.
±MTV…
C
A
B
R
E
S
T
S
E
A
S
Y
O
N
R
U
B
B
E
R
M
O
U
N
T
S
C
A
B
R
E
S
T
S
E
A
S
Y
O
N
R
U
B
B
E
R
M
O
U
N
T
S
M939-Series Trucks…
Hydraulic Oil
Reservoir Draining
Report cracking on cab support mounts…
…before they start to disintegrate
drivers, when doing your
weekly pmcs on your fmtv,
don’t forget
to take a look at
the front cab support mounts.
ouch!
I
wish they’d
replace my
cab support
mounts!
these
bumps are
killin’
me!
mechanics, the hydraulic oil
reservoir for the m929- and
m930-series dump trucks
needs to be drained and
refilled annually.
Drain oil from bottom line
±ill here and check line for leaks
The upper mount, NSN 5342-01-3
7
1-
7
9
7
3,
and lower mount, NSN 5342-01-3
7
1-
7
258,
will deteriorate over time.
First you’ll notice splits in
the rubber. Soon after they’ll
begin to disintegrate.
679.10-11.indd
1-2
5/4/09
5:26:16 PM
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