engine

Engine Mount - Rear

for 1970 AMC Rebel Machine 390ci V8 · RWD

Difficulty

Moderate

Time

2.5 h

Tools

Steps

🤖AI-generated, not yet human-verified. This walkthrough was produced by AI and may contain errors. Treat it as a guide, cross-check every step and torque value against the manufacturer's service manual, and stop if anything looks unsafe. This is a moderate-risk job — take extra care.

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

Warnings

⚠️Never work under a vehicle supported only by a jack. Always use jack stands rated for the vehicle weight.

⚠️Ensure the engine is properly supported before removing mount bolts. Engine falling can cause severe injury or death.

⚠The rear transmission mount shares load with the rear engine mount. Verify transmission mount condition before proceeding.

ℹ️Apply penetrating oil to all mount fasteners at least 30 minutes before starting work to ease removal.

Tools required

Floor jackEssential

Jack standsEssential

Engine support bar or chain hoistEssential

Block of wood (approximately 2x6x12 inches)Essential

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

Combination wrench setEssential

Torque wrenchEssential

Penetrating oil

Wire brush

Pry bar

Parts

Rear engine mount × 1 — Use OEM specification for 1970 AMC 390ci V8
Engine mount bolts (if corroded) × 1 — Grade 8 hardware recommended

Preparation

Park vehicle on level, solid ground and engage parking brake
Chock the front wheels securely
Allow engine to cool completely if recently operated
Disconnect negative battery cable
Spray all engine mount fasteners with penetrating oil and allow to soak

Procedure

1
Raise and support vehicle
Raise the front of the vehicle using a floor jack at the front crossmember. Support the vehicle securely on jack stands placed under the front frame rails. Ensure the vehicle is stable before proceeding underneath.
2
Support the engine
Position a floor jack with a block of wood under the engine oil pan, centered and toward the rear. Raise the jack until it just contacts the pan but does not lift the engine. Alternatively, install an engine support bar across the fender edges with a chain to support the engine from above. The engine must be securely supported before proceeding.
3
Locate rear engine mount
From underneath the vehicle, locate the rear engine mount at the back of the engine block where it connects to the transmission bellhousing area. The mount consists of a rubber isolator with mounting brackets bolted to both the engine/bellhousing and the crossmember. Inspect the mounting hardware and note the configuration.
4
Remove crossmember-to-mount bolts
Using appropriate sockets and wrenches, remove the bolts securing the rear engine mount to the crossmember or frame bracket below. These are typically two bolts accessible from underneath. Support the mount as you remove the final bolt to prevent it from falling.
5
Raise engine slightly
Carefully raise the floor jack under the oil pan approximately 1/2 to 1 inch to create clearance and relieve tension on the upper mount bolts. Raise slowly and watch for interference with hood, accessories, or firewall components. Do not raise more than necessary.
6
Remove engine-to-mount bolts
Remove the bolts securing the upper portion of the rear mount to the engine block or bellhousing. These bolts thread into the engine and may be difficult to access. Use swivel sockets or box-end wrenches as needed. Keep track of bolt locations if different lengths are used.
7
Remove old mount
With all fasteners removed, extract the old rear engine mount from between the engine and crossmember. It may require gentle prying or wiggling to free it from its position. Inspect the mount for signs of failure such as cracking, separation, or oil deterioration.
8
Clean mounting surfaces
Use a wire brush to clean the mounting surfaces on both the engine/bellhousing and the crossmember bracket. Remove any rust, old gasket material, or debris. Inspect the threaded holes in the engine block and clean threads if necessary using a thread chaser.
9
Position new mount
Position the new rear engine mount in place between the engine and crossmember. Align the mount with the bolt holes on both the upper and lower surfaces. You may need to adjust the jack height slightly to achieve proper alignment.
10
Install engine-to-mount bolts
Install the upper bolts that secure the mount to the engine block or bellhousing. Start all bolts by hand to ensure proper thread engagement. Tighten bolts in an alternating pattern to draw the mount evenly into place. Torque to manufacturer specification (typically 40-50 ft-lbs for this application, verify with factory service manual).
11
Lower engine onto mount
Slowly lower the floor jack under the oil pan, allowing the engine weight to settle onto the new rear mount. Lower until the mount is properly compressed and the lower mounting holes align with the crossmember bracket.
12
Install crossmember-to-mount bolts
Install the bolts that secure the lower portion of the mount to the crossmember or frame bracket. Start all bolts by hand first, then tighten in an alternating pattern. Torque to manufacturer specification (typically 35-45 ft-lbs, verify with factory service manual).
13
Remove engine support and lower vehicle
Remove the floor jack or engine support bar from the engine. Lower the vehicle from the jack stands and remove stands. Lower the vehicle completely to the ground.

Reassembly

Reconnect the negative battery cable
Start the engine and observe the rear mount for proper operation and any unusual vibration
Verify all mount bolts remain tight after initial engine operation

Verification

With engine running, check for excessive engine movement or vibration indicating improper mount installation
Visually inspect all mount bolts to ensure they are properly tightened and seated
Road test the vehicle and verify no unusual vibrations or driveline movement during acceleration and deceleration
Re-torque all mount fasteners after 100 miles of operation