MACS Monthly Newsletter - 2022 - DEC7

Suppliers, for their part, also have significant responsibility
when it comes to A/C system layout and
performance. Their diligence in maintaining clean and
reliable production lines has a direct effect on the quality
of the A/C system. A/C lines must be properly cleaned of
flux salts and other contaminants and thoroughly dried
before they are assembled in the vehicle (Figure 18).
Figure 15: Left: Comparison between a damaged valve
housing after being brazed onto the line vs an identical
new part. Right: Valve core with damage from debris in
the housing at installation.
Figure 18: It doesn't take a large piece of debris to cause
a leaky valve. Even fibers off a clean rag or T-shirt can
create a leak, if they find their way onto the valve o-rings.
Valve cores must be clean and leak-free when inFigure
16: Left: Core with contaminant left from the
housing braze process. Right: Contaminant trapped in
the valve core from factory system evacuation/fill.
Equally as critical as thoughtful A/C system design
and layout is availability of replacement parts.
OE part number listings could be easier to access,
and some OE parts are nearly impossible to obtain
exact replacements for. Distributors make obtaining
OE parts possible, but without a known part number,
identifying the correct part can still be difficult
(Figure 17).
stalled into the A/C line for factory fill, and they must
be identifiable for replacement during A/C system service.
Factory and service couplers must be cleaned
and maintained frequently to prevent damage to the
service ports, limit debris introduction into the A/C
system, and ensure a proper seal. After fill, sealing
caps must be properly installed, and they must also be
identifiable and available for replacement when the vehicle
is serviced.
What Can MACS Repair Shops Do to Minimize
Service Port Damage and Leakage?
What does this mean for the automotive and mobile
air-conditioning industry? For now, the most important
steps to take are hopefully ones already being taken:
Source parts and tools from reputable sources. This
includes replacement sealing caps!
If you notice a service tool damaging the service
ports or valves, clean and repair or replace the tool.
See Figure 19.
Figure 17: Brazing is a difficult step in the A/C line manufacturing
process. Any flux or salt that remains in the
A/C line or housing attacks the brass valve cores and
the aluminum valve housings. Cleaning the lines of braze
residue includes a flushing and drying process to ensure
the lines are properly cleaned. The corrosion visible inside
this housing can be the cause of a leaky system,
either by eating away at the surface that the valve core
seals to, or by damaging the valve core seals directly.
December 2022
7
Figure 19: Low side M8 core with the installation bridge
broken after installation at the vehicle assembly line. With
this type of failure, it may be possible for the system to seal,
but this core cannot be removed without special tools
MACS Service Reports
Schrader Pacific
Schrader Pacific
Schrader Pacific
Schrader Pacific
Schrader Pacific
MACS Monthly Newsletter - 2022

Table of Contents for the Digital Edition of MACS Monthly Newsletter - 2022
