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Get to k
know your Setra
S S 417
7 suspensio
on

The Setrra suspensio on system is a wonderful thing — but before you can c truly undderstand it, yo ou have
to know how the coa ach air systemm works. The ere are three
e delivery line
es leaving thhe air dryer: primary
p
(drive axxle) brakes, secondary
s d accessory (everything eelse) air.
(frront/tag axle ) brakes, and

Since the
e suspension ssory air pre ssure, that's the circuit we're
n uses acces w going too examine.

All air prressure for th

Figure 1
On all cooaches made e from 2011 to present (S
S 417 TC and S 407 CC)), the valve iss mounted on n the
rear of th
he accessoryy air panel (s
swing-down p e roof of the spare-tire coompartment. See
panel) on the
Figure 2.

Figure 2
Next, thee air goes thrrough a pres
ssure regulattor, set to 95 psi, and on to a distributtion block. Th
here are
four of th
hese pressurre regulators in the accesssory system m, and three are
a used for the suspens sion. The
fourth is for the entra
ance door annd the rest off the accessoory air. See Figure
F 3.

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Figure 3
From thee distribution oes to three leveling valv
n block, air go ves: one for the front susppension and two for
the rear suspension. Photos on the right in Fiigure 4 show w earlier mufffler (obsoletee); all valves should
be upgraaded to the red muffler sh hown on left..

Figure 4
These th
hree leveling valves contrrol the ride h
height of the coach.
c To av
void confusioon, refer to th
he air
gure 5 offers an accessorry-system ov
schemattic below. Fig verview.

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Figure 5
Figure 6 shows the air
a routing fro
om the tank tthrough the 120
1 psi presssure protectioon valve (A), through
a 95 psi pressure reg
gulator (B) and on to the distribution block
b (C).

Figure 6
Figure 7 shows air flo
ow from the distribution b
block to each
h of the leveling valves.

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Figure 7
Lastly, F
Figure 8 show
ws air flow fro
om the leveliing valves to
o each of the axle air belloows.

Figure 8
An addittional feature
e of the Setra
a suspensionn is the inclus
sion of two pressure reguulators incorp
porated
into the d
drive-axle su
uspension. These regulattors are set tot 60 psi and are an "insuurance policyy" to
maintainn some air prressure in the
e drive-axle ssuspension in
i the event of
o a major aiir-system faillure.
Refer to the components identifie ed with the a rrows in Figu
ure 8.

4