Tires - Unusual Rear Wear Patterns

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Models:
1984-86 Sentra &
1983-86 Pulsar NX

Section:
Wheel & Tire

Classification:
WT88-001

Bulletin No.:
TS88-017

Date:
February 22, 1988


REAR TIRE WEAR


This bulletin supersedes Technical Bulletin WT85-006 and WT87-001. Please reference this bulletin in the respective Technical Bulletin books.


APPLIED MODELS:
1984-1986 Sentra and 1983-1986 Pulsar NX, SERVICE INFORMATION

Some 1984-1986 Sentra and 1983-1986 Pulsar NX vehicles may exhibit unusual rear tire wear patterns. There are two different types of tire wear (Type A and Type B). An incident vehicle may exhibit either or both types.





Type A

Type A tire wear is best described as smooth, even wear on the outside shoulder of the tire, and the wear may be unequal on right and left tires. The following factors will increase the rate of Type A tire wear:

1. Low or uneven tire pressure.
2. Abrasive road surfaces.
3. Frequent high vehicle loads.
4. Rear toe-in near the specification limit.





Type B

Type B rear tire wear is best described as a diagonal scrub pattern with cupping. This irregular rear tire wear is caused by a combination of the following:

1. Excessive rear tire/wheel imbalance or tire non-uniformity.
2. Frequent high vehicle loads.
3. Rear toe-in near the specification limit.


Use the following Service Procedure and Parts Information to reduce the rate of rear tire wear on incident vehicles.

It is very important that tires with irregular wear be replaced (if wear is severe) or rotated to the front wheels (if wear is mild).

SERVICE PROCEDURE





Use the chart to determine which steps to perform for the incident vehicle.


Step 1. Early Sentra Wagon Models: Refer to Technical Bulletin RA88-001
and replace the bushing in both lower control arms with countermeasure parts.

Step 2. Early Sentra Wagon, Sentra Sedan, and Pulsar Models: Replace the
rear coil springs with countermeasure parts.

Step 3. All Models: Balance both rear tire/wheel assemblies.

Step 4. All Models: Adjust the rear suspension to maximum toe-out position
as follows:

a. Drive the vehicle onto a ramp-type hoist that supports the vehicle by its tires.





b. Loosen the rear lower control arm bolts.


c. Pull both rear control arms inward toward the center of the vehicle by fastening a power puller (also known as a come-along) around the lower shock absorber mounts.

d. While maintaining tension of less than 100 lbs. on the lower control arms, torque the rear lower control arm bolts to 43-51 ft./lb.

e. Remove the power puller.

Perform Step 5 on Sentra Sedan, Coupe and Pulsar vehicles only if they exhibit Type B rear tire wear:

Step 5. Road test the vehicle and check for seat/floor pan vibration and rear

spindle fore and aft movement at highway speeds (50-65 mph). This is best detected by having an observer follow the incident vehicle in a separate vehicle and watch the rear wheels while traveling at highway speeds. If the incident vehicle exhibits rear spindle fore and aft vibration after adjusting rear toe, install, the countermeasure rear control arm bushings and repeat Step 4. The owner should be made aware that this change will slightly decrease ride comfort.





PARTS INFORMATION





DO NOT install countermeasure springs and control arm bushings on Wagon vehicles built AFTER the following VINS. DO NOT install countermeasure springs on Sedan and Coupe vehicles built AFTER the following VINS. Vehicles built after these VINs have the countermeasure springs and replacement of these parts will not reduce rear tire wear.





WARRANTY INFORMATION


* Wagon models produced 9/83 through 3/85.