by John Pfanstiehl
Corvette engine compartments are inhospitable for rubber. The high temperatures, oil and gas vapors and infrared heat from exhaust manifolds are tough on AC hoses. Fortunately these hoses often are easy to change. Zip Corvette offers many AC hoses as complete assemblies and at a reasonable price. Follow along to see what is involved with changing those hoses, along with some helpful tips.
After replacing an AC hose, the system should be held at a high vacuum to remove any water or moisture that may have entered. A vacuum pump and gauge set can be borrowed from several auto parts chain stores. If you don’t want to vacuum the system and install the refrigerant, just take the car to an AC repair shop. You still can be happy in the knowledge that you saved labor costs for the hose replacement and had the right part installed the way you want.
01: A new AC Condenser Liquid Line for a 1973 Corvette arrived quickly from Zip Corvette. Replacement hoses should have the proper size rubber O-rings on the fittings and plastic caps to keep dust and debris from getting inside the hoses. These are made in the USA.
02: Consider getting a new AC V-belt, like this 1973 350ci Air Condition Belt. Zip Corvette has these available with the original imprinting on the outside with GM part number, size, manufacture’s logo and codes. You can specify the desired quarter of manufacture and they are made in the USA.
03: A 1973-1977E VIR Maintenance Kit is also advisable if the system has a replaceable desiccant bag. Replacing the VIRs of 1973 to 1977 early-build Corvettes is fairly easy. Note: the desiccant packaging should not be opened until ready to install and the system is ready to vacuum. Other AC systems may have a Drier/Receiver like AC Drier/Receiver for 1968-72 Corvettes. All are made in the USA.
04: Check to make sure that the fittings and pipe bends on the replacement hose are identical to the old hose. A number of different AC hoses were used over the years on Corvettes. This hose is for 1973 only.
05: The shiny oily area on the flap is a telltale to the AC leak. If oil is seen on the hood over the front of the compressor, its front seal is leaking. In this case, the oil leak came from the installation of an aftermarket sight glass. Tip: most replacement hoses now have a hard plastic barrier lining which doesn’t seal well on metal nipples when used with standard hose clamps.
06: Oil should be added to the AC System if a considerable amount has leaked out. Be aware that there are a number of different oils used in auto AC Systems and not all are compatible. This system still had R12 Freon and used mineral oil.
07: Install the more difficult hose end first. In this case, it was the connection to the VIR assembly. This was best accessed from below. Use one hand to rotate and move the free end to help align the other end. Tip: heating the new hose can make it more flexible and easier to bend.
08: Make sure to hold the evaporator or condenser fitting to prevent rotating its metal tube when disconnecting these hoses. If the fitting turns, its joint may break at the condenser or evaporator, causing more work and expense.
09: When both ends of the hose are connected, and the hose is routed the proper way, tighten the fittings. They don’t have to be very tight, because the O-rings do the sealing. Applying a little AC oil or antiseize compound on the threads will make any future disassembly easier.
10: Connect the high and low pressure hoses of the gauge set if you are vacuuming the system. On this system, the low side hose connects to the VIR. That location is very tight, and may require modifying a right angle adapter.
11: The gauge set’s high side hose connects to the hose block on the rear of this compressor. Tip: after the system is charged, disconnect the gauge hoses when their respective pressures are at minimum. For the high side, that means when the engine is off and for the low side, when the AC is on.
12: A vacuum pump was available as a loan from the local auto parts store. You pay for it up front and then they reimburse you when you return it. The center (yellow) hose on the gauge set connects to the vacuum pump.
13: The vacuum pump soon attained a vacuum over 29”HG. This level of vacuum held for over an hour after the pump was shut off, indicating no leaks are likely. The high vacuum is used to boil and remove any water or moisture from the system.
14: After installing just over 3 pounds of R12, the pressures were right on target at 29.5 and 250 psi. Tip: placing the refrigerant cans in hot water increases the pressure inside the can to speed delivery into the system. Job completed – now it’s time to be cool again.
1963-1982 Corvette AC Hose Replacement
Source: Zip Corvette Parts
8067 Fast Lane | Mechanicsville, VA 23111 | (800) 962-9632
Corvette Parts List Related to Article:
- 69-72 350 AC Condenser Liquid Line
- 69-72 427/454 AC Condenser Liquid Line
- 73 AC Condenser Liquid Line
- 73-77E VIR Maintenance Kit
- 68-72 AC Drier/Receiver
- 73 350ci Air Condition Belt
- Shop/Service Manuals
Related Corvette Magazine Articles:
- 1973-1977E Corvette VIR Eliminator Installation and VIR Maintenance (coming soon)