evac/recharge, refrigerant recovery, and alignment

[Semidevil]

2 questions:

If a bodyshop requests to evacuate and recharge on the air conditioner, is 'refrigerant recovery' also necessary? I was always under the impression that the 'evacuate' part of evacuate & recharge is the same thing as refrigerant recovery. can someone explain.

With car alignments, can a car that is able to take a 4-wheel alignment also take 2-wheel alignment. I know that if a car is 2 wheel drive, 4 wheel alignment would be excessive. What about a 4-wheel drive taking a 2 wheel alignment?

 

[TekViper]

Evacuate/recovery is essentially the same thing. Most shops have an a/c machine that will recover most of the refridgerant charge (evacuating the system). After the charge has been recovered, depending on what is being done, it can then pull a vacuum in the system to remove any moisture in the system. The longer it is left on a vacuum, the more moisture will be removed. Typically it will not require more then 20 minutes unless the system is old or has been left open for a long period of time.

There are some vehicles that you can "get away" with a 2 wheel alignment, but a 4 wheel alignment is always recommended, even if your vehicle only has adjustments for 2 wheels. For example, say you have a RWD pickup truck with a solid rear axle, there are no adjustments you can make to the rear axle/wheels (unless it has sustained heavy damage, in which case you are looking at more then just a regulare alignment) but the front wheels you can set camber, caster, and toe. The benefit of having a 4 wheel alignment on this type of vehicle is sensors are placed on the rear wheels (non adjustable) and will compensate alignment specifications of the front wheels to match the rear axle more precisely. Without the rear sensors being mounted, you are aligning the front wheels to where the rear wheels are "supposed" to be, but may no longer be do to age and wear.

Most any alignment these days should always be a 4 wheel alignment, even if your car doesn't have adjustments available at all 4 wheels. Difference in price comes in how many adjustments need to be made and how difficult the adjustments are to make.

 

[Semidevil]

Originally posted by: TekViper
Evacuate/recovery is essentially the same thing. Most shops have an a/c machine that will recover most of the refridgerant charge (evacuating the system). After the charge has been recovered, depending on what is being done, it can then pull a vacuum in the system to remove any moisture in the system. The longer it is left on a vacuum, the more moisture will be removed. Typically it will not require more then 20 minutes unless the system is old or has been left open for a long period of time.

so if a bodyshop requests to 'evacuate/recharge' AND 'refrigerant recovery,' are they double charging me?

thanks.

 

[steppinthrax]

Make sure if they are going to be evacuating and recharging the system that they do a leak test. They should fill the system up with nitrogen to above operating pressures and test with soap/water.

Then they should evacuate and if they are using a computerized evacuator (robinair)charger it usually holds the pressure for 15 mins or so and test for pressure drops. Then it will drop in refridgerant.

If there is a leak even a small one and air gets into the system your starting all over again and most likely replacing the dessicant.