GM Astro/Safari 1985-1996 Repair Guide

Leaf Spring

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In order to maintain proper suspension balance and vehicle handling, leaf springs should be replaced only in axle sets.

REMOVAL & INSTALLATION



1985-94 Vehicles

See Figures 1 and 2



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Fig. Fig. 1: Exploded view of the leaf spring mounting-1985-94 vehicles



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Fig. Fig. 2: Adjusting the rear suspension trim height

The following procedure requires the use of 2 jackstands and 2 floor jacks.

  1. Raise and support the rear of the vehicle safely using jackstands.
  2.  

When supporting the rear of the vehicle, support the axle and the body separately to relieve the load on the rear spring. Because the axle may need to be raised or lowered, you probably want to support the van using the jackstands and secure the rear axle to the floor jacks.

  1. Remove the rear wheel and tire assemblies.
  2.  
  3. Remove the shock absorber.
  4.  
  5. Remove the nuts from the U-bolt and lower plate (attaching the spring to the axle at the center of the spring). If the vehicle is equipped with a stabilizer bar it will be necessary to remove the lower nuts, washers and clamps. If necessary, swing the stabilizer bar down to obtain clearance when lowering the axle assembly.
  6.  

The U-bolts, nuts and washers should be discarded when removed and replaced with new parts upon installation.

  1. Remove the U-bolt, lower plate and anchor plate, then CAREFULLY lower the axle away from the spring.
  2.  


WARNING
DO NOT let the axle hang by the brake hose at any point during the procedure or the hose may be severely damaged.

  1. At the rear of the fiberglass spring, loosen (but DO NOT remove) the shackle-to-frame and the shackle-to-spring nuts and bolts.
  2.  
  3. At the front of the fiberglass spring, remove the retainer-to-hanger assembly nuts, washers and the retainer(s).
  4.  
  5. At the rear of the fiberglass spring, remove the spring-to-shackle nut, washer and bolt.
  6.  
  7. Remove the fiberglass spring from the vehicle.
  8.  

To install:
  1. Attach the spring to the shackle (DO NOT tighten the nuts/bolts), rotate the shackle forward to clear the rear bumper bracket, position the spring into the slot on the hanger and attach the retainer-to-hanger fasteners.
  2.  
  3. Using the axle supports, raise and position the axle housing under the fiberglass spring. Using NEW U-bolts, nuts and washers, along with the lower plates, connect the axle housing to the spring.
  4.  

When installing the axle housing, be sure the full weight of the axle is resting on the supports; the fiberglass spring MUST NOT support any of the axle weight.

  1. Torque the axle U-bolt-to-spring nuts to 48 ft. lbs. (65 Nm) and the axle lower plate-to-spring nuts to 41 ft. lbs. (55 Nm).
  2.  
  3. To adjust the rear suspension trim height, perform the following:
    1. Raise the axle/spring assembly until the clearance between the top of the axle and the bottom of the frame is 5.3-6.1 in. (135-155mm).
    2.  

  4.  

If the axle supports are not in complete contact with the axle housing and resting firmly on the floor, damage to the spring and axle could result.

    1. Tighten the shackle retainers to 81 ft. lbs. (110 Nm) for 1985-89 vehicles. For 1990-94 vehicles tighten the shackle-to-frame bolt to 81 ft. lbs. (110 Nm) and the shackle-to-spring bolt to 103 ft. lbs. (140 Nm).
    2.  
    3. Tighten the retainer-to-hanger assembly nuts to 28 ft. lbs. (38 Nm).
    4.  

  1. Install the shock absorber to the axle housing.
  2.  

When installing the shock absorber on the right side, be sure to position the parking brake bracket on the bolt before the nut is installed.

  1. Install the wheel assemblies, then remove the jackstands and carefully lower the vehicle.
  2.  

1995-96 Vehicles

See Figures 3 and 4



Click image to see an enlarged view

Fig. Fig. 3: Exploded view of the leaf spring mounting-1995-96 vehicles



Click image to see an enlarged view

Fig. Fig. 4: Measuring the rear suspension trim height

The following procedure requires the use of 2 jackstands and 2 floor jacks.

  1. Raise and support the rear of the vehicle safely using jackstands.
  2.  

When supporting the rear of the vehicle, support the axle and the body separately to relieve the load on the rear spring. Because the axle may need to be raised or lowered, you probably want to support the van using the jackstands and secure the rear axle to the floor jacks.

  1. Remove the rear wheel and tire assemblies.
  2.  
  3. For 1995 vehicles, remove the shock absorber.
  4.  
  5. On 1996 vehicles, if necessary for access to the lower spring plate front nut, remove the axle bumper and retainer.
  6.  
  7. Remove the nuts securing the U-bolt and lower plate (attaching the spring to the axle at the center of the spring). If the vehicle is equipped with a stabilizer bar it will be necessary to remove the lower nuts, washers and clamps, then swing the stabilizer bar down to obtain clearance when lowering the axle assembly.
  8.  
  9. Remove the U-bolt, lower plate and anchor plate, then CAREFULLY lower the axle away from the spring.
  10.  


WARNING
DO NOT let the axle hang by the brake hose at any point during the procedure or the hose may be severely damaged.

  1. At the rear of the fiberglass spring, remove the shackle nut and bolt, then disengage the spring from the shackle.
  2.  
  3. At the front of the fiberglass spring, remove the hanger nut and bolt, then remove the spring from the hanger and from the vehicle.
  4.  

To install:

To assure proper seating and attachment of the anchor plate over the spring end and the axle, the installation procedure must be followed closely.

  1. Position the spring to the hanger, then loosely install the retaining nut and bolt.
  2.  
  3. Position the spring to the shackle, then loosely install the retaining nut and bolt.
  4.  
  5. CAREFULLY raise the axle until it contacts the spring.
  6.  
  7. Apply rubber lubricant to the isolator on the spring in order to aid installation of the anchor plate, then install the anchor plate to the top of the spring.
  8.  
  9. Install the lower plate and U-bolt around the axle and through the anchor plate. If your van is equipped with a stabilizer bar it will be necessary to install the clamps, washers and nuts.
  10.  
  11. Install the nuts to the lower plate and U-bolts. Starting with the inner (lower plate side) nuts, gradually tighten the 4 nuts so the anchor plate moves uniformly, side-to-side, over the spring. Tighten the nuts to 52 ft. lbs. (70 Nm) for 1995 vehicles or to 41 ft. lbs. (56 Nm) for 1996 vehicles.
  12.  

After tightening the fasteners to specification, there should be no gap between the anchor plate, axle tube bracket and the lower plate. A metal-to-metal contact should exist.

  1. Raise the axle so the vehicle's weight is supported by the spring. The rear suspension height should be approximately 5.3-5.7 in. (135-145mm). With the suspension at normal ride height, tighten the shackle and hanger retainers to 81 ft. lbs. (110 Nm) for 1995 vehicles or to 74 ft. lbs. (100 Nm) for 1996 vehicles.
  2.  
  3. If removed on 1996 vehicles, install the axle bumper and tighten the nut to 33 ft. lbs. (45 Nm).
  4.  
  5. For 1995 vehicles, install the shock absorber.
  6.  
  7. Install the tire and wheel assemblies.
  8.  
  9. Remove the jackstands and carefully lower the vehicle.
  10.  

 
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