Remove and replace the air conditioning accumulator (receiver-drier) on a 1966 Chevrolet Corvette with factory AC system, including refrigerant recovery and system recharge.

Warnings

Tools required

Parts

• AC accumulator/receiver-drier × 1 — Use OEM specification or Four Seasons 33001
• Refrigerant oil (mineral oil for R-12 systems) × 1 — Use mineral oil compatible with R-12, 2-3 oz
• Refrigerant line O-rings × 2 — Use OEM specification, size varies by connection

Fluids

• R-12 refrigerant (or EPA-approved substitute) — 0.875 qt

Preparation

1. Verify refrigerant type by checking service port labels or system decals
2. Park vehicle on level surface and set parking brake
3. Ensure engine is cold before beginning work
4. Gather all replacement parts and verify correct accumulator for your system
5. Connect refrigerant recovery machine to service ports and verify machine is ready for operation
6. Have plastic caps or plugs ready to immediately seal open refrigerant lines

Procedure

1. 1

   Recover refrigerant from AC system
   Connect recovery machine to both high and low-side service ports. Follow machine manufacturer's procedure to completely recover all refrigerant from the system. Monitor gauges until both high and low side read 0 PSI or vacuum. Allow recovery machine to run full cycle to ensure all refrigerant and oil are captured. Record the amount of refrigerant recovered for recharge reference.
2. 2

   Locate the accumulator assembly
   The accumulator is located on the passenger side of the firewall area, mounted vertically near the evaporator outlet. It is a cylindrical metal canister approximately 3 inches in diameter and 9 inches tall with refrigerant lines entering from the bottom and exiting from the top. On 1966 Corvettes, access is from the engine compartment.
3. 3

   Remove accumulator mounting bracket
   Remove the 2 bolts securing the accumulator mounting bracket to the firewall or inner fender support. Use an open-end wrench to hold the bracket nuts while loosening bolts if necessary. Support the accumulator by hand as you remove the last fastener.
4. 4

   Disconnect inlet refrigerant line
   Using a flare nut wrench to prevent rounding, carefully loosen the inlet line connection at the bottom of the accumulator. This line comes from the evaporator outlet. Once loose, unthread the connection completely by hand. Immediately cap both the open line and accumulator port with plastic plugs to prevent moisture entry and debris contamination.
5. 5

   Disconnect outlet refrigerant line
   Using a flare nut wrench, loosen the outlet line connection at the top of the accumulator. This line goes to the compressor suction port. Unthread completely and immediately cap both the open line and accumulator port. Inspect both disconnected lines for damage or corrosion at the flare fittings.
6. 6

   Remove old accumulator
   With both lines disconnected and mounting bracket removed, carefully remove the old accumulator from the vehicle. Invert it over a measuring cup to drain and measure any residual refrigerant oil. Record this amount. Inspect the drained oil for debris, metallic particles, or discoloration which may indicate compressor or system problems.
7. 7

   Prepare new accumulator
   Remove shipping caps from new accumulator ports. Add the appropriate amount of fresh mineral refrigerant oil to the new accumulator: if 2 ounces or less drained from old unit, add 2 ounces; if more than 2 ounces drained, add the same amount that was removed. Pour oil slowly into the inlet port.
8. 8

   Install new O-rings on refrigerant lines
   Remove the old O-rings from both the inlet and outlet refrigerant line fittings. Clean the fitting surfaces with a shop rag. Install new O-rings onto each line fitting, ensuring they are properly seated in their grooves. Lightly coat the new O-rings with clean mineral refrigerant oil to aid installation and sealing.
9. 9

   Position and connect new accumulator
   Position the new accumulator in the mounting location with the inlet (bottom) and outlet (top) ports oriented correctly. Remove the plastic cap from the inlet port on the accumulator and the evaporator line. Connect the inlet line hand-tight, then snug with a flare nut wrench. Do not fully torque yet. Remove caps from outlet port and compressor line, connect hand-tight, then snug with wrench.
10. 10

    Secure accumulator mounting bracket
    Install the mounting bracket around the accumulator and align with the firewall or fender support mounting holes. Install the 2 mounting bolts and tighten securely. Ensure the accumulator is held firmly without crushing the canister.
11. 11

    Torque refrigerant line connections
    Using flare nut wrenches, torque the inlet and outlet line connections to proper specification. Apply firm pressure to achieve a leak-free seal without over-tightening which can damage flare fittings. Typical specification for these connections is 15-20 ft-lbs, but verify for your specific fittings.
12. 12

    Evacuate the AC system
    Connect vacuum pump to system service ports using manifold gauge set. Open both high and low side valves. Run vacuum pump for minimum 45 minutes to achieve deep vacuum (29+ inches Hg). Monitor gauges for vacuum hold: close valves, shut off pump, and observe for 10 minutes. Vacuum should hold steady; if it rises, there is a leak that must be found and repaired.
13. 13

    Recharge AC system with refrigerant
    With system under vacuum and holding, prepare to charge with R-12 refrigerant (or approved substitute). Connect charging equipment to low-side port. Introduce refrigerant slowly following gauge set instructions. System capacity is 3.5 pounds (approximately 56 ounces) for the 1966 Corvette factory system. Charge to the amount recovered in Step 1, or to factory specification if significantly different. Monitor high and low side pressures during charging.

Reassembly

1. Verify all refrigerant line connections are tight and properly torqued
2. Ensure accumulator is securely mounted and not in contact with any sharp edges or moving components
3. Double-check that no tools or materials were left in the engine compartment

Verification

• Start engine and set AC controls to maximum cooling and high blower speed
• Allow system to run for 5 minutes, then check low-side pressure (should be 25-35 PSI) and high-side pressure (should be 180-250 PSI at 75-85°F ambient)
• Verify cold air is blowing from vents, with vent temperature reading 40-50°F colder than ambient
• Use electronic leak detector or soap solution to check all connections at accumulator for refrigerant leaks
• Monitor system operation for 15 minutes to ensure pressures stabilize and remain within normal range
• Check compressor cycling: it should engage smoothly and cycle off when adequate cooling is achieved

More procedures for this vehicle