Tips and Tricks For Automotive
A/C & Cooling System Service

Please send comments, corrections and additions to: PParish@delanet.com

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You must consider the safety of the tips listed below.
Try them at your own risk!
Testing with Nitrogen
Our Nitrogen Tank Setup
Picture of Nitrogen Test Setup
We have taken the nitrogen tank fitting supplied to us by our welding supply house and attached a 1/4" pipe thread tee. Then we added a 1/4" male pipe thread by 1/4" male flare adapter to one end and a high pressure relief valve to the other. The relief valve we used is like one that comes on a shop air compressor with a setting of 150 PSI. When we want more pressure we hold pressure on the stem of the relief valve.
Spring Lock Fittings
When you service a Springlock fitting make sure that the inside of the fitting is clean before you put it back together. Clean the male and female Springlock fitting parts with a scotch brite pad. Then clean the o-ring groves by drawing a string back and forth through them. Put on new R134a (green) o-rings covered with mineral oil.
Flushing Components
We only flush air conditioning components that are free flowing like the condenser, evaporator and lines. We squirt the mineral sprits into the component with a squirt bottle. The solvent coming out will show how dirty the component is and whether it is free flowing. After we flush the component with solvent we pop it dry. Pop it dry means we hold the rubber tipped blow gun tight on one end and hold our finger tight over the other and then release. It is important to make sure you have dry shop air. We use a Milton rubber tip blow gun. We add a short piece of 1/2" refrigerant hose over the blow guns' tip when needed. We grind one end of this short piece of hose to a point like the blow gun.
Flushing A/C Systems
Tight Fittings
If we have a fitting that will not push into a hose we pour boiling water over it. We pour slow and in a way that it does not get into the hose.
Flourescent Tracer Dye
We put flourescent dye in every vehicle that has a leakage history. If the vehicle is partially charged we mix the dye with oil and inject it with a oil injector.
Tracer Products provides a full line of flourescent leak dye they call "Tracerline". They have a flourescent leak dye (TP-3840) that is compatible with mineral oil, PAG oil, Ester oil and Alkyl Benzene oil.
Tracer Products Address
Stuck Orifice Tube
To get out stuck or broken orifice tubes we use heat. A heat gun would be the best bet. After applying heat we either blow the tube out or use a pick tool that we have made. Do not blow with to much pressure and be sure to ketch it with multiple layers of shop rags.
Installing Orifice Tube
Picture of Tool
If a orifice tube will not go back into the line or evaporator we use a tool to clean up the inside. We turn the bolt into the line with an air ratchet. The tool acts as a scraper as it is turned into the line clockwise. It is a simple tool to make.
    Take a 10mm x 120mm bolt and:
  1. Cut off the threaded part of the bolt.
  2. Round the sharp edge left from the cut just slightly.
  3. Cut a 1/8" to a 1/4" grove in the bolt length wise with a hack saw.
  4. The grove in the bolt acts as a scraper. Grind or file down the leading edge of the hack saw cut. I placed a piece of sheet metal in the grove as I cut down the leading edge. This was to make sure I did not cut any of the trailing edge.
  5. Then knurl up the trailing edge by rubbing it from the side with a round piece of steal or a screw driver.
SPECIAL FITTING
Everco and Murray offer a special fitting to convert old vacuum pumps to R134a use. Its part number is 409546.
Four Seasons also offers a special fitting to convert old vacuum pumps to R134a use. Its part number is 59214.
I use a Robinair air vacuum pump with no moving parts for R134a use.
Special Tool to Rethread Fitting
Picture of Tool
I have made some rethreading tools by cutting existing steel fittings.
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PParish
70 North West St.
Dover, DE 19904
DATE: Jan. 21, 1997
E-mail address: PParish@delanet.com/