MACS Monthly Newsletter - 2022 - DEC6

SAE J639 defines the service port geometries and
system pressures for R-134a and R-1234yf systems.
The current definition of " accessible " service ports
has not prevented the frequent need for service
port access extenders, so this would be updated in
the standard text. Sealing caps used on SAE J639
systems would need to be compliant with the new
sealing cap standard, and meet a minimum refrigerant
leak rate. And in order to avoid repeated system
design mistakes of using incompatible materials,
a material compatibility test requirement has been
proposed (Figure 13).
When will SAE decisions affect the service
industry?
The process to write a new J-standard is lengthy,
but not impossible. Another revision to SAE J639
would likely also take at least 2 - 4 years to get adopted
by the EPA, even if the updates are intended to
reduce lifetime vehicle emissions. OEs may choose
to exceed the minimum EPA requirement, but they
are not required to.
What can OEs/suppliers/service shops
do to improve the current service ports
environment?
Many OEs are guilty of poor service port placeFigure
13: Valves Left to Right: R-134a High Side with
M10 core, R-1234yf High Side Integrated Valve, R-1234yf
Low Side with Standard Core, R-134a Low Side with
North American M8 Core. The coupler interfaces of these
valves are wholly defined by SAE J639. The cap and customer
(braze end) interfaces are defined by the suppliers.
How will SAE recommendations and changes
affect the service industry?
Standardizing sealing caps will help reduce confusion
in locating replacement parts, and system
pressure/refrigerant leak requirements will reduce
refrigerant loss.
Couplers per " new SAE spec " should simplify the
search for a quality, non-damaging coupler, if manufacturers
follow the specification and advertise their
products under the specification number. But this
is not the same as having only compliant couplers
available for purchase and use.
New service port accessibility requirements that
define " accessible " would reduce the need to frequently
use service port extenders.
December 2022
6
Figure 14: Not all valve housings are designed equal!
Design mistakes like this one happen too often - in this
case, the core can be held open by the housing, preventing
the system from sealing when the coupler is removed.
And not all damaged and leaky systems pulling
into the bay left the assembly line intact - there are
many steps at the line manufacturing and vehicle
assembly plants that can damage the valve or core,
or introduce excessive heat or contaminant that reduces
valve life. See Figures 15, 16.
MACS Service Reports
ment. But a few do take care to keep the service
port easily accessible. A careful system design
could eliminate hours of labor and expensive extenders
used to access and service poorly located
service ports. Quality system design is more than
just placing components where they can be seen - it
includes considering the size of the service equipment.
Just because you can reach into the engine
bay and grab onto the service port doesn't mean the
port is accessible to couplers or pressure switches.
If the service port is so inaccessible the cap has
to be removed with long-nose pliers, that port will
probably never have a sealed cap installed again
(Figure 14).
Schrader Pacific
Schrader Pacific
MACS Monthly Newsletter - 2022

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