hvac

AC Compressor

for 1970 AMC Rebel Machine 390ci V8 · RWD

Difficulty

Moderate

Time

3.5 h

Tools

Steps

This procedure covers the removal and replacement of the air conditioning compressor on a 1970 AMC Rebel Machine with 390ci V8 engine.

Warnings

⚠️AC refrigerant must be recovered by certified equipment before disconnecting any lines. Releasing refrigerant to atmosphere is illegal and dangerous.

⚠️Refrigerant can cause severe frostbite. Wear safety glasses and gloves when working with AC system.

⚠Original 1970 systems used R-12 refrigerant which is no longer available. System may have been converted to R-134a or other substitute.

⚠Use only the correct compressor oil type for your refrigerant. Mixing oil types will damage the system.

Tools required

AC refrigerant recovery machineEssential

Socket set (3/8" and 1/2" drive)Essential

Wrench set (standard)Essential

Line wrench setEssential

Serpentine belt tool or pry barEssential

Torque wrenchEssential

AC manifold gauge setEssential

Vacuum pumpEssential

Safety glassesEssential

Drain pan

Wire brush

Parts

AC compressor × 1 — Use OEM specification or aftermarket equivalent for York inline compressor
Compressor mounting gasket or O-rings × 1 — Check compressor kit
AC refrigerant R-12 or approved substitute × 1 — Typically 3 lbs capacity for this system
Compressor oil × 1 — Use mineral oil for R-12 or appropriate for substitute refrigerant
V-belt for compressor × 1 — Replace if worn or cracked

Preparation

Park vehicle on level ground and engage parking brake
Allow engine to cool completely if recently operated
Disconnect negative battery cable
Verify AC system refrigerant type by checking under-hood labels or previous service records
Gather AC recovery equipment and ensure proper certification for refrigerant handling

Procedure

1
Recover refrigerant from AC system
Connect AC recovery machine to service ports on the system. Follow recovery machine instructions to completely remove all refrigerant from the system. Allow adequate time for complete recovery, typically 15-30 minutes. Note the amount recovered for reference during recharge.
2
Remove compressor drive belt
Locate the compressor V-belt on the front of the engine. On the 390ci V8, the York compressor is typically mounted on the passenger side. Loosen the compressor mounting bracket adjustment bolt and pivot bolt to create slack in the belt. Slide the belt off the compressor pulley, crankshaft pulley, and any idler pulleys.
3
Disconnect refrigerant lines from compressor
Using line wrenches to prevent damage to fittings, disconnect the suction line (larger diameter) and discharge line (smaller diameter) from the rear of the compressor. Cap all open fittings immediately with plastic caps or tape to prevent moisture and debris entry. Have a drain pan ready to catch any residual compressor oil.
4
Disconnect compressor electrical connections
Locate and disconnect the compressor clutch electrical connector. On the Rebel Machine, this is typically a single wire connector near the compressor body. Note wire routing for reinstallation.
5
Remove compressor mounting bolts
Remove the compressor mounting bracket bolts that secure the compressor to the engine block. The York compressor typically has two or three mounting bolts on the bracket plus a pivot bolt. Support the compressor weight while removing the final bolt. Carefully maneuver the compressor out of the engine bay, being mindful of surrounding components.
6
Prepare new compressor for installation
Drain shipping oil from new compressor according to manufacturer instructions. Add the correct amount and type of compressor oil as specified for your refrigerant type (mineral oil for R-12, PAG or POE for R-134a conversions). Typical oil capacity is 8-10 ounces. Rotate compressor clutch by hand several times to distribute oil internally. Install any new gaskets or O-rings on compressor fittings.
7
Install new compressor
Position the new compressor onto the mounting bracket, aligning bolt holes. Install mounting bolts finger-tight initially. Ensure compressor is properly seated and aligned with pulley plane matching other engine pulleys. Tighten mounting bolts in a cross pattern to secure compressor firmly to bracket. Verify compressor pulley rotates freely without binding.
8
Reconnect refrigerant lines
Remove caps from compressor fittings and refrigerant lines. Install new O-rings if applicable, lightly coating with compressor oil. Thread fittings by hand first to ensure proper alignment, then tighten with line wrenches. Suction line and discharge line should be snug but avoid over-tightening aluminum fittings.
9
Reconnect electrical connection and install belt
Reconnect the compressor clutch electrical connector. Install the V-belt over the compressor pulley, crankshaft pulley, and any idler pulleys. Adjust belt tension by moving compressor on bracket adjustment slots. Belt should deflect approximately 1/2 inch under firm thumb pressure at the longest span. Tighten adjustment bolt and pivot bolt to secure compressor position.
10
Vacuum test the system
Connect vacuum pump and manifold gauges to AC service ports. Pull vacuum on system for minimum 30 minutes, ideally 45-60 minutes. System should reach and hold 28-30 inches of vacuum. Close manifold valves and monitor for 10 minutes. Vacuum should not drop more than 2 inches, indicating no leaks. If vacuum drops significantly, locate and repair leak before proceeding.
11
Charge AC system with refrigerant
With vacuum pump off and valves closed, connect refrigerant source to manifold gauge set. Charge system with appropriate refrigerant type to specification (typically 2.5-3 lbs for this system). Reconnect battery negative cable. Start engine and set AC controls to maximum cold and high fan. Continue charging on low-side port only with engine running until proper pressures are achieved. Typical running pressures: low side 25-35 psi, high side 180-250 psi depending on ambient temperature.

Reassembly

Verify all refrigerant line connections are tight and show no signs of oil seepage
Check compressor drive belt tension and adjust if needed after first hour of operation
Ensure all tools and materials are removed from engine compartment

Verification

Start engine and turn AC to maximum cold setting
Verify compressor clutch engages when AC is turned on (clicking sound and pulley engages)
Check that cold air is being produced at dashboard vents within 2-3 minutes
Monitor AC pressures with gauges to confirm proper system operation
Inspect all connections for refrigerant leaks using electronic leak detector or soap solution
Verify no unusual noises from compressor during operation
Test AC performance after 15-minute run time to ensure consistent cooling