A Crash Course on Retrofits - BodyShop Business

A Crash Course on Retrofits

As a collision repair specialist, air-conditioning service is part of your job. When your customers bring in their cars for repairs, you want to offer them all the services required.

The less you farm out, the more profit you make on the job – which
is probably one of the reasons you decided on in-house A/C service
to begin with. With almost 47 percent of all collisions involving
the replacement of the front fascia, grille, hood and front fenders
– as well as their related underhood components – there’s a big
market for A/C repairs.

Little did you know that production and use
of the popular refrigerant R-12 would eventually be banned due
to environmental concerns – leading to tougher regulations regarding
repairs, refrigerants, recovery and recyling. Automakers worldwide
have chosen R-134a as the long-term replacement for R-12 in automotive
A/C systems. Vehicles purchased in the United States since the
1993 model year are already equipped with R-134a systems. But
because older models don’t have R-134a-compatible systems, the
solution for these vehicles is retrofitting.

What does this mean for your shop’s continued
A/C servicing?

If you have customers in for work that includes
the replacement or repair of the entire A/C system or some of
its components, it makes sense to offer them the opportunity to
upgrade or retrofit the existing system so it can accommodate
R-134a refrigerant.

Why Retrofit?

CFC production for air-conditioning and refrigeration
uses was banned in 1996. However, the existing supply of CFCs
can be used until it’s gone. According to the U.S. Environmental
Protection Agency (EPA), the United States will see spot shortages
in the supply of R-12 – a refrigerant identified as being one
of the leading contributors to ozone depletion – beginning this
summer, with severe shortages nation-wide in 1998.

Retrofitting alleviates customer concerns
about hazards or complications related to substitute refrigerants
– the only alternative to retrofitting once R-12 is obsolete.
Some of these refrigerants are marketed as “true drop-ins”
and “direct drop-ins for R-12 automotive use.” But the
truth is, there’s no such thing as a direct replacement for R-12
or R-134a refrigerant.

There are, however, nine EPA-approved R-12
substitute refrigerants for use in cars. Though these blends work
in an R-12 system, pose little health threat, have no ozone-depleting
characteristics and are inexpensive, many use hydrocarbons – such
as propane – which are flammable.

When these refrigerants are used, a hazard
is posed to any A/C service technician when he connects the high-side
and low-side hoses of a recycling machine to a car and tries to
recycle what he thinks is R-12 or R-134a. If an A/C system contains
a substitute refrigerant and the technician is unaware, gaseous
hydrocarbons – like propane – may be exposed to a 110VAC compressor
in the recycling machine, presenting a serious risk of fire and

Also, once customers choose to use a blend
refrigerant, they’re tied to using that particular refrigerant
– the A/C system has been modified and tested to accept only that
product. If, at some point, the blend isn’t available, the customer
has to choose between having the system reconfigured again or
going without service.

When weighing the benefits of retrofitting,
the cost of R-12 should also be considered. Like anything in short
supply, the price of this refrigerant has increased dramatically.
Right now, the cost of a 30-pound cylinder of R-12 is about $600
– six times more expensive than a like amount of R-134a. Because
of its cost, the smuggling of refrigerant into the United States
is second only to that of illegal drugs.

Essential Equipment

If you’ve decided to offer retrofitting as
a shop service, your first step is to purchase the necessary equipment.
As an A/C service provider, you’re required by law to invest in
R-134a service equipment. Without the proper equipment, the possibilities
of cross-contamination exist.

All equipment that recovers or recycles refrigerant
must be approved by the EPA or an approved equipment-testing organization.
Also, refrigerant extracted by recover-only equipment must be
recycled on site using approved equipment owned by the same person
or sent to an EPA-approved reclaimer prior to reuse. If you handle
multiple refrigerants, you must have equipment designed for each
type of refrigerant.

One of the most important pieces of equipment
for any A/C service provider is a refrigerant identifier, which
tells you what each car’s refrigerant system contains.

Why is identifying refrigerants so important?

Though R-12 and R-134a are the most commonly
used refrigerants in automobiles, more than nine different types
of refrigerant compounds are now legally being used; many others
– including propane – are illegally being used. None of these
refrigerants can be mixed with any other and continue to exhibit
optimal cooling properties. If a foreign refrigerant is introduced
into an A/C system not designed to use that compound, the A/C
system will experience accelerated deterioration.

For example, on the surface, it would appear
that there’s no problem with mixing R-12 and R-134a. After all,
R-134a was designed to mimic R-12’s pressure and temperature characteristics.
However, when you mix as little as 3 percent of R-12 with R-134a,
you get a new mixture with a higher discharge pressure than either
refrigerant has alone. This higher pressure can cause A/C system
performance problems, lead to the failure of the compressor and
other A/C components, and damage the refrigerant recovery/recycle
machine. To avoid such damage, the SAE J1661 R-134a retrofit standard
calls for no more than 2 percent residual R-12 in a newly retrofitted
R-134a system.

Note: The only person responsible for what’s
in an A/C system is the technician who physically put the compounds
in the system. Those who sell refrigerants aren’t responsible
for any contamination effects; they may choose to refund a purchaser’s
money, but they have no legal responsibilities.

Other equipment needed to perform an A/C retrofit
includes leak detectors for hoses and couplings, a gauge set,
hand tools to remove and replace “O” rings and service-port
couplings, a vacuum pump, a thermometer and correct high-side
fitting adapters.

Retrofit Right

The surest way to avoid problems, ensure repeatable
A/C retrofit success and achieve the best possible performance
for consumers is to know the basic retrofit procedures that will
help you retrofit right regardless of the systems you encounter.

  • Visually inspect all components of the current A/C and heating
    systems. Both systems must be functioning properly for a conversion
    to be successful.
  • Use a refrigerant identifier to positively establish that
    the A/C system you’re about to convert contains only R-12. If
    a system is found to contain an unknown refrigerant, do not connect
    your recovery/recycling machine. Be sure to use an identifier
    that also detects excessive noncondensable gases (air). As little
    as 2 to 3 percent air in a refrigerant charge will cause excessive
    head pressures and noisy compressor operation.
  • Leak check the system. Be sure to use R-12-rated leak-detection
    equipment and methods approved by SAE standard J1628.
  • Connect the R-12-rated service station or gauges and run a
    performance test. Record pressures and duct temperatures to use
    after conversion.
  • Thoroughly remove the R-12 from the system with a UL-approved
    recycling machine.
  • Remove the compressor from the vehicle. If the compressor
    is to be reused, the existing refrigerant oil must be drained
    and measured.
  • Remove and inspect the orifice tube or expansion valve. If
    the tube shows any debris in the filter screen, it should be replaced.
  • Remove the filter drier or accumulator; drain and measure
    the oil.
  • Flush the condenser. This needs done especially if there was
    a compressor failure or the orifice tube or expansion valve filter
    screen was plugged.
  • Before converting the system, perform the necessary repairs
    with R-134a-rated components.
  • Install the proper type of oil in the system. R-12-system
    mineral oil should be replaced with oil recommended by the OE
    or component manufacturer.
  • Install a new filter drier or accumulator with XH7 or XH9
    desiccant. This will provide the greater moisture absorbency needed
    in R-134a systems.
  • Permanently install conversion fittings using a thread-locking
    chemical or mechanical method.
  • Install a high-pressure cut-off switch if one isn’t already
  • Install conversion label(s). When possible, cover or remove
    the original R-12 label to prevent confusion during future servicing.
  • Connect the R-134a equipment and evacuate for 30 minutes (minimum)
    or longer for best results. The dual evaporator system should
    be evacuated for one hour.
  • Recharge the system to approximately 80 percent of its original
    R-12 charge level. Follow OE or component manufacturer’s recommendations
    if available.
  • Run a performance check and compare the duct temperature and
    system pressure to previous readings.
  • Leak check the retro-converted system with SAE J1628 equipment
    and procedures.

The Cost of Retrofitting

After all the discussion about regulations, equipment and procedures,
any shop owner still interested in performing retrofits is wondering,
“How much can I charge for this service?”

The amount you’ll be able to charge is a factor of what the market
will bear based on the amount of time spent on the job and the
components and parts used. This can vary depending on the condition
of the system and the number and type of components replaced or
upgraded. The following are some things that can increase the
cost of an A/C retrofit:

  • If the receiver drier/accumulator has old-style XH-5 desiccant
    (which is not compatible with R-134a) or has newer XH-7 or XH-9
    desiccant that’s saturated with moisture;
  • If the compressor is badly clogged or failed and needs replaced;
  • If the condenser needs to be replaced by a more effective
    multiflow condenser, or an auxiliary puller or the pusher fan
    needs to be mounted on the existing condenser;
  • If the system has serious leaks at the hoses and other connections;
  • If the system was topped off with an unknown refrigerant,
    requiring toxic-waste disposal.

It’s important to remember that retrofitting – unlike pinstriping,
window tinting or sunroof installation – isn’t a profit center.
It’s an extension of your existing A/C service that will help
you better serve your customers and contribute to the automotive
industry’s effort to meet new regulations to protect the environment.

Writer Melissa Green is managing editor of BodyShop Business.

Some information in this article was provided by Snap-on Tools.
Information for the “Retrofitting Right” checkpoints
and “The Cost of Retrofitting” was provided by Everco.

Caution: Highly Flammable!

The threat of fire and explosion from hydrocarbon refrigerants
is real. The Florida chapter of the Association of Arson Investigators
set up its own tests regarding the flammability of these compounds.
The results are frightening.

In one test, the driver’s-side door frame was bent out 1 1/2 inches
from the roof frame, and the driver’s-side rear door was separated
2 inches from the roof frame. As if that weren’t enough, three
vehicle windows were destroyed, and glass from the windows was
found as far away as 90 feet. A fireball traveled 8 to 10 feet
from the car as it dissipated, and the shock caused by the flash
was strong enough to set off a motion detector in a car parked
375 feet away.

Speaking from Experience

by Bob Leone

An operating R-12 system that’s cooling OK and isn’t leaking is
generally thought to be a perfect candidate for an HFC-134 upgrade,
right? Wrong.

As a former shop owner in Colorado, I learned to be selective
in appropriating vehicles for retrofitting. When is retrofitting
appropriate? A crunched condenser or damaged compressor is one
condition for advising a customer to retrofit to HFC-134, for

If you’re just starting to retrofit, the easiest first attempts
are late-model light trucks, in particular, General Motors ’85
and newer cars and trucks. Most offer easy access to components
for draining mineral oil, as well as simplified service-port upgrading.

Note: If you specialize in retrofits on GM vehicles, like we
did, then replace the accumulator and/or receiver dryer on any
units dated earlier than 1993. Stock a bunch of the universal
dryers and change the orifice tube. Part 15-1491 is a filter for
in-line installation that has an orifice tube built in – a clever
idea that might catch on. This combo gives you a head start on
future service routines and can improve vapor-thermal conductivity
by allowing for improved flow.

Some of the vehicles we encountered were more difficult to work
with – for instance, early, automatic-temperature-control (ATC)
Lincolns and late-model Saturns are hard to get the old oil out.
A few vehicles are best to retrofit with factory kits – such as
Volvo and Mercedes. The OE kits I’ve seen are much more complete
than they previously were, and new prefab hoses with acme-style
HFC-134 service ports instead of port-replacement fittings work
best in some installations.

The Biggest Complaint

In our experience, the biggest complaint we’ve heard regarding
retrofits from R-12 to HFC-134 is decreased fuel mileage. It’s
not uncommon to lose one to three miles per gallon.

Let’s take a closer look at the problem.

If your GM vehicle retrofit takes a bigger condenser, a more aggressive
fan or a pusher fan assembly, the additional weight you add will
eat away at fuel mileage. How do you compensate for the weight
increase? If you’re going to replace a GM radial compressor with
a new unit, take the time to locate a new, lightweight compressor
with a six-pole electromagnetic clutch assembly. By using this
3/8-inch shorter unit, you can shave 3 1/3 pounds off the vehicle’s
curb weight. You’ll also provide for a stronger drive coupling
to assist in pumping against higher high-side pressures. The weight
lost by using the new compressor will help counter that gained
with the other components.

On some GM trucks, you may be able to catch a break if they have
over-size radiators that already run engine-oil-cooler heat exchangers.
These big guys already have the mondo condensers with a lot more
baffles and fins.

Bigger radiators will help keep a truck cool, but vapor-thermal
conductivity levels are still a hard nut to crack with HFC-134.
It’s tough to give up heat with such high average temperatures
at the heat-exchange unit.


Kits available for retrofit are packaged with esther oil, either
natural or synthetic. The synthetic stuff is pretty good for systems
you might be able to drain, but I prefered to use the biodegradable
esther; whenever it appeared, we’d have to flush. Keep in mind
that manufacturers say any remaining flush residue will only enhance
system operation. Both types of kits have a good flushing medium,
leaving a conditioning chemical additive optional.

Some kits give you a selection of blue or green “O”
rings that can be used for captured or free-style installation
on hoses or fittings. It’s a good idea to dump your old R-12 seals
and schrader service-fitting cores because the new blue and green
rings work well on R-12 systems, too.

Hoses and Fittings

A/C systems that are in good shape normally have hoses that are
in good shape; but, be aware that on some older installations,
such as those using axial-style compressors and POA valving, the
molecular transitional properties of HFC-134 can cause a marginal
hose to leak right away. If you have a hose, even a barrrier-style
hose, with a center leak, replace it. Swage or end-fitting leakers
can be cut off and reswaged using a bubble-style crimping tool.
Barb-style hoses can present problems when trying to repair an

Though most kits give you new angled or straight HFC-134 service-port
adapters that are designed to screw on over the old R-12 stuff,
remove entirely or replace the valve cores with the new material
type and add lubricant to the system by pouring it through the
adapter or injecting it with a syringe before you get the new
fittings in place. Most kits have a locking compound or interference
thread fit to discourage tampering with the new 134-style fittings
once they’re installed. Filters are a good idea and come with
a few kits. When clearance problems prevent using the old service
points for installation of new retrofitting service fittings,
use a valve and saddle clamp to create a totally new service port.

Note: Be aware that, eventually, you’re going to come across a
retrofit or “spook” installation (no parts other than
fittings and maybe oil) that’s using another variety of hook up.
This is mandated by law for the other drop-in substitutes the
EPA has approved. The chance of cross contamination is pretty
heavy in such a case. We avoid fooling around with systems like


The guys at GM have relented, as of late, and are down from seven
to three types of PAG oil for their original-equipment compressors.
We preferred esther and found that PAG and mineral-oil cocktails
simply don’t have any future as multiservice lubricants and that
reliability suffers as a result of mixed lubricant characteristics.
The mineral oil likes to “hang” in the accumulator.
When replacing an orifice tube, be sure to look for oil pockets
in the evaporator and get all of the sludge that may be lurking
in the bottom of the unit.


Deep vacuum (50-micron rated vacuum pump) means 30 minutes in
a deep cycle, and then recharging to approximately 85 percent
by weight of the original R-12 volume. Some bigger systems can
use 90 percent, but don’t forget that the high-pressure cut-off
switch (a necessity in the conversion process) will cut the compressor
clutch if you overcharge and bring the pressure on the high side
up too high.

The Clutch Switch

Cycling-clutch-switch adjustment or replacement may also be required.
We allow the system pressure on the low side to coast down a bit
before re-engagement of the clutch. This saves a little gas and
takes away some of the annoying clicking and clacking that might
go on with some small-capacity systems. A neat pusher-fan relay
can be wired to the clutch cycling circuit and will go off and
on with the clutch – cutting fuel waste and noise.

Retrofitting Dos and Don’ts

  • Invest in good equipment, this includes the recovery and recycling
    gear for R-12, as well as for HFC-134. Also, don’t forget to leak
    check with your R-12 recover/recycle unit after removing the refrigerant
    from the original system. Measure and record pressures and temperatures
    for later reference. The cycling-clutch duty cycle also should
    be kept in mind.
  • Buy a refrigerant identifier – a device that can check purity,
    test for cross contamination and rule out flammable drop-in refrigerants.
  • Black-market refrigerant can have as much as 5 percent or
    more moisture content, which is bad news for valving and compressors.
    When using PAG, the filter dryer will give up the ghost in record
  • Keep an assortment of spring-lock repair kits for those Ford
    and other systems that use this type of connector. We’re all aware
    of the leakage problems that R-12 exhibits when minor contamination
    works its way into the couplings. The higher pressures and tenacious
    molecular activity of HFC-134 make matters even worse.
  • Labeling retrofits may be the most important step in the process.
    Use one or more labels and, when possible, cover or remove the
    old R-12 affixed label.
  • If you were fortunate enough to start with a reliable, functional
    R-12 system and you’ve recorded pressures and evaporator temperatures,
    then your final performance and leak checks will go smoothly.
    Otherwise, consult applicable pressure-temperature charts, use
    your combo or dedicated “sniffer” leak detector to seek
    out problem areas and, last but not least, take advantage of kit
    maker and equipment builder technical help lines to get you through
    the tough ones.
  • Current part numbers for replacement dessicant used with R-12
    systems will not, in my experience, degrade the system if used
    with an HFC-134 upgrade. Still, XH/7 and XH/9 are the recommended
    dessicant materials for the new systems. Because we always used
    esther, 134 “O”-ring material, barrier replacement hoses,
    and new

R-12/134 dessicant-compatible accumulators and dryers, we can
advise others that long-term planning for upgrade conversion does

Writer Bob Leone, a retired shop owner, is ASE Three-Way Master
Certified and is completing qualifications as a post-secondary
automotive instructor in the vocational school system in Missouri.

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