SERVICE MANUAL
The service nylon tubing will be marked at regular
intervals
with
name,
number,
type,
size
and
manufacturing code designations.This
marking
is
intended to positively identify the tubing and prevent
substitution of inferior quality tubing.
TRAILER BRAKE HOSE COUPLING AND DUMMY
COUPLING
Hose couplings provide a convenient means for
connecting and disconnecting air lines between tractors
and trailers. When two couplings are joined, their
packing rings are forced together under pressure to form
an air tight seal.
Dummy coupling is the term given to those couplings
which are used to keep dirt or foreign matter out of the
air lines when they are not being used. Dummy couplings
are either rigidly mounted to the truck or fastened by a
chain.
TEST
1.
With hose couplings connected and brakes
applied, coat the hose couplings with soapsuds
to check for leaks. No leaks allowed.
2.
Leakage
results
from
worn,
damaged,
or
improperly installed packing rings.
REPLACEMENT
1.
At least once a year or if leaking, the hose
coupling should be disassembled, cleaned and
serviced.
2.
Remove old packing ring by prying out with a
screwdriver. Be sure packing ring groove is
thoroughly cleaned.
3.
Install new packing ring by partially collapsing it
with the fingers, (Fig. 8 ) and entering one side
of flange in groove in coupling.
4.
Work the remaining part of the packing ring into
place with a blunt nosed screwdriver or similar
tool (Fig. 9). Exposed face of packing ring will be
flat and free of any bulges when properly
installed.
TRAILER
BRAKE
HOSE
ASSEMBLIES
AND
CONNECTORS
Trailer brake hose assembles are used for making
flexible connections between components on the truck
which change positions in relation to each other or for
making flexible connections between the tractor and
trailer. Hose lines or couplings at the rear of tractor are
marked by tags identifying them as "SERVICE" or
"EMERGENCY".
Fig. 8 Installing Packing Ring In Hose Coupling
1Packing Ring
2Hose Coupling
Fig. 9 Using Screwdriver to Complete Packing Ring
Installation
1Blunt Nosed Screwdriver
2Packing Ring
3Hose Coupling
Test
1.
If a line is suspected of being restricted, remove
and blow air through it in both directions. Air
passage through hose must not be obstructed in
any way.
2.
To check for leaks, apply the brakes and coat
hose and connections with soap suds. No leaks
are permitted. Leakage at hose connectors is
CTS-4079 - CHAPTER XII - Page 6