Preliminary Inspection:

^ Inspect tires for excessive, uneven wear - replace if necessary.
^ Equalize tire pressures.
^ Torque leaf spring-to-axle U-bolts to high limit
of specification (150 ft.lbs. or 2 03 N-m). See Section 3C for tightening order.
^ Equalize parking brake adjustment.
^ Adjust rear service brakes to .030" running clearance.
^ Inspect and record front end alignment readings - adjust total toe to specifications (.0" to .14"). Inspect caliper brake line bolt (#34, page 5A8, Figure 4, 1988 Service Manual X-8832) for mislocation of orifice. The orifice should be located in the unthreaded part of the bolt. If the orifice is located in a threaded portion of the bolt, then the bolt must be replaced.

NOTICE: After the preceding inspections and/or adjustments have been made, the vehicle should be road tested to determine if a lead still exists. Vehicles that lead may lead either right or left when the brakes are applied.

Make all stops on a dry, level (no crown), clean roadway.

FIGURE 1 - CALIPER/KNUCKLE CLEARANCES:

IMPORTANT!

EACH APPLICABLE STEP MUST BE THOROUGHLY COMPLETED TO EFFECT A LASTING REPAIR. FAILURE TO COMPLETE THE PROCEDURE EXACTLY AS WRITTEN MAY RESULT IN AN UNSATISFACTORY REPAIR.


Conduct a series of 5 stops from 55 MPH bringing vehicle to a stop in 5 seconds (15 FPS Sq.). Record amount and direction of lead. Do not slide or lock wheels.

* FPS Sq or Ft/Sec2 is the measurement used for calculating the deceleration rate with a decelerometer. Use of decelerometer, when available, is the preferred method.


PROCEDURE A


Right or left lead


Remove and discard the brake calipers and pads


Refinish brake rotors per Chart 1 (or replace brake rotors if they cannot be brought into spec.)

Inspect and/or adjust front wheel bearing per the procedure in Service Manual Section 3C

Install new Delco Moraine brake calipers See Parts Information for part numbers

Install new Delco Moraine brake pads See Parts Information

Bleed front brakes


Inspect caliper to knuckle clearance. It should be between .010" - .024" in total. If necessary, file the knuckle to obtain clearances. Equalize all upper and lower clearances per Figure No. 1.

Perform 12 stop burnish procedure. Burnish procedure is mandatory.

12 Stop burnish procedure

1st Stop From 40 MPH taking 6 seconds to stop (10 FPS SQ)*
2nd Stop to
11th Stop From 55 MPH taking 5 seconds to stop (15 FPS SQ)*
12th Stop From 40 MPH taking 6 seconds to stop (10 FPS SQ)*


Drive 1/2 (0.5) miles between burnish stops.

Drive 4 miles after 12th stop to cool system.


To confirm if vehicle is repaired, conduct series of 5 stops from 55 mph bringing vehicle to stop in 5 seconds (15 FPS SQ.) and compare to initial stops.

FIGURE 2:

FIGURE NO. 3 - Ball Joint Turning Effort:

If the lead condition still exists, perform the following procedure:


PROCEDURE B:


Inspect front spring bushings for visible deterioration. Replace as necessary.


Install a modified #3 spring leaf (P/N 460359) on vehicles currently equipped with two leaf springs as follows:

From the middle of the center bolt hole in the new #3 spring leaf, measure forward approximately 2-1/2 inches. Mark this point and cut using a suitable tool such as a panel cutter. Remove any roughness from the cut end of the spring and "round" the upper cut edge with a die grinder. Install the springs under the second leaf where a third leaf would normally be located. See Figure No. 2.


Refer to the alignment specifications previously recorded and increase caster angle to + 10.0 degrees using the proper steel caster wedge (P/N provided in Parts Information). Install the steel caster wedge between the axle pad and the spring pad. The thicker end of the wedge should be positioned toward rear of the vehicle.


Disconnect tie rod ends. Measure Ball Joint turning effort and correct as required. See Figure No. 3 and accompanying instructions.


Reconnect tie rod, torque to spec. 40 ft.lbs. (55 N-m).
Position front wheels straight ahead


Disconnect drag link at steering gear


Center steering gear using procedure specified in Section 3B.


Adjust drag link to reconnect to steering gear


To confirm vehicle is repaired, conduct series of 5 stops from 55 mph bringing vehicle to stop in 5 seconds (15 FPS SQ.) and compare to initial stops.


If the lead condition still exists, perform the following:

PROCEDURE C


Replace rotors if not replaced in Procedure A. If rotors were replaced in Procedure A rotate them from side to side.


Make a series of 5 stops from 55 mph, bringing vehicle to a stop in 5 seconds. (15 FPS SQ.) Record findings.