Strut Mount - Rear

This procedure addresses replacement of rear shock absorber upper mounts on a 1972 Ford F-100, which uses traditional leaf spring suspension with shock absorbers rather than struts.

Warnings

Tools required

Parts

• Rear shock absorber upper mounting kit (rubber bushings and hardware) × 2 — Use OEM specification or Monroe/Gabriel equivalent
• Rear shock absorber lower mounting kit (if deteriorated) × 2 — Use OEM specification

Preparation

1. Park vehicle on level, solid ground and engage parking brake firmly
2. Place wheel chocks in front of both front wheels
3. If upper shock mounts are rusted or corroded, apply penetrating oil to all mounting nuts and bolts, allow 15-30 minutes to soak
4. Gather all tools and replacement parts before beginning work
5. Verify replacement shock mount kits match original configuration (rubber bushing type and diameter)

Procedure

1. 1

   Raise and support rear of vehicle
   Using the floor jack at the rear differential center section, raise the rear axle until the tires are approximately 2-3 inches off the ground. Position jack stands under the frame rails just forward of the rear axle mounting points. Lower the vehicle onto the jack stands while keeping the floor jack in position under the differential with slight upward pressure to control axle movement. The axle should hang freely but remain supported enough to prevent excessive droop.
   ⚠️Ensure jack stands are positioned on solid frame rail sections, not on brake lines, fuel lines, or body panels. Verify stands are locked in position before working under vehicle.
2. 2

   Access driver side upper shock mount
   Working from underneath the vehicle, locate the driver side rear shock absorber upper mount on the frame rail. On most 1972 F-100 configurations, the upper mount is secured with a single nut on a threaded stud extending from the shock body, mounting to a bracket on the frame rail. The shock eye will have a rubber bushing and washer assembly.
   ℹ️Some bed configurations may require removal of bed-mounted toolboxes or trim panels for clear access.
3. 3

   Remove driver side upper shock mounting nut
   Using an appropriately sized socket and ratchet (verify wrench size on the actual fastener, commonly 11/16" or 3/4" on this era Ford), remove the upper shock mounting nut from the threaded stud. The shock may need to be held from below to prevent spinning. If the stud spins freely, use a 9/16" wrench on the lower nut (if accessible) or grip the shock body with a pry bar to stabilize it. Remove the upper washer and rubber bushing, noting the orientation and order of components for reassembly.
   ⚠If the mounting stud is severely corroded and breaks off during removal, the shock absorber must be replaced entirely as the stud is typically pressed or welded into the shock body.
4. 4

   Remove driver side lower shock mounting
   Working underneath the vehicle, locate the lower shock mounting bolt at the rear axle or axle mounting bracket. This is typically a bolt passing through the shock eye and axle bracket. Using the correctly sized socket and wrench for the bolt head and nut (verify hex size on the actual fastener), remove the bolt and nut. Support the shock absorber as you remove the lower mounting to prevent it from falling.
5. 5

   Remove driver side shock absorber
   With both upper and lower mounts disconnected, remove the shock absorber from the vehicle. Inspect the lower mounting bushings and hardware for wear or damage. If the lower bushings are deteriorated, they should be replaced at this time.
6. 6

   Clean and inspect driver side mounting points
   Using a wire brush, clean the upper mounting stud area on the frame and the lower mounting bracket on the axle. Remove all rust, dirt, and old rubber residue. Inspect the frame mounting hole for cracks, elongation, or damage. Inspect threads on the upper stud for damage. If threads are damaged beyond repair, the shock must be replaced.
7. 7

   Install new driver side upper mount bushings
   Install the new rubber bushing onto the shock upper stud according to the mounting kit instructions. Typically, the assembly order from bottom to top is: lower washer, lower rubber bushing (wide end down), shock mounting eye, upper rubber bushing (wide end up), upper washer, and retaining nut. Verify correct orientation before proceeding.
8. 8

   Install driver side shock absorber
   Position the shock absorber with the upper stud inserted through the frame mounting hole. Hand-thread the upper retaining nut onto the stud but do not tighten yet. Align the lower shock eye with the axle mounting bracket and insert the lower mounting bolt. Install the lower nut and hand-tighten.
9. 9

   Torque driver side shock mounts
   With the vehicle weight still on the jack stands and the axle hanging at ride height or slightly compressed, torque the upper shock mount nut and the lower shock mount bolt to the factory service manual specifications (verify exact values before final tightening). Do not over-torque the upper stud nut, as excessive torque crushes the rubber bushing. Verified detail (The torque specifications of 65 ft-lb upper and 70 ft-lb lower seem high for 1972 F-100 shock mounts, which typically used smaller 3/8" or 7/16" hardware with torque values in the 25-40 ft-lb range for both upper and lower mounts.): With the vehicle weight still on the jack stands and the axle hanging at ride height or slightly compressed, torque the upper shock mount nut to 25-30 ft-lb and the lower shock mount bolt to 40-50 ft-lb.
   ⚠Do not torque shock mounts with the axle fully extended or compressed beyond normal ride height, as this can preload the rubber bushings and cause premature failure.
10. 10

    Repeat for passenger side
    Repeat steps 2 through 9 for the passenger side rear shock absorber, following the same removal, cleaning, inspection, and installation procedures. Maintain consistent torque values on both sides.
11. 11

    Remove jack stands and lower vehicle
    Using the floor jack under the differential, raise the rear axle slightly to relieve pressure on the jack stands. Remove both jack stands from under the frame rails. Slowly lower the vehicle to the ground, ensuring the shock absorbers compress smoothly and no interference occurs.

Reassembly

1. No disassembly of other components was required for this procedure

Verification

• Visually inspect both upper and lower shock mounts to ensure all hardware is properly installed and torqued
• Rock the vehicle side-to-side and front-to-back to verify shock absorbers are functioning and no rattling or loose components are present
• Drive the vehicle at low speed over minor bumps to confirm proper shock operation and absence of noise from mounting points
• Re-inspect all mounting hardware after 50-100 miles of driving to ensure no loosening has occurred
• Verify no contact between shock bodies and frame, axle, or suspension components through full suspension travel

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