File in Section:
Bulletin No.:

Service Bulletin

Date:

15-NA-068
December, 2015

TECHNICAL
Subject:

Front Lower Ball Joint and Knuckle Inspection After Road Hazard Tire/Wheel Damage
and/or Noise from Front End

Attention: This Bulletin also applies to any of the models that may be Export vehicles.
Brand:

Model:

Chevrolet

Corvette

Model Year:

VIN:

from

to

2014

2016

from

Engine:

Transmission:

All

All

to

Condition

Some customers may comment on a ticking/clicking/metallic grinding noise heard from
front suspension area or lash in steering wheel after a severe road or track front
suspension impact.

Cause

This condition may be due to damage on the lower ball joint to steering knuckle
connection.

Correction
The front steering knuckle and lower ball joint need to
be inspected following the procedure below.

Service Procedure:
1. Raise and support the vehicle. Refer to Lifting and
Jacking the Vehicle in SI.
2. Starting on left front, grab the wheel and tire at the
top and bottom, pushing on one side and pulling on
the opposite side to manually test the tire/wheel for
lateral movement.
Note: There should be NO perceived movement.
3. Complete the same lateral movement test on the
right front wheel and tire.
Note: The right side should also display NO perceived
movement and should mimic the left side.
• If NO discernible lateral movement is noted,
continue to step #4 and inspect the knuckle/
lower control arm joint interface.
• If discernible lateral movement IS noted, jump
ahead to the Lower Control Arm and Steering
Knuckle Replacement procedure in SI.

Copyright 2015 General Motors LLC. All Rights Reserved.

4. Inspect the knuckle to lower control arm joint
interface, following the steps below:
4.1. Remove the appropriate front tire and wheel
assembly. Refer to Tire and Wheel Removal
and Installation in SI.
4.2. Support the lower control arm with a suitable
jack stand.
4.3. Loosen the lower ball joint nut at the knuckle.
The lower control arm should separate from
the knuckle.
Note: If the link does not automatically separate from
the knuckle, use Special Tool CH-42188-B separator.
Note: If Special Tool CH-42188-B separator alone fails
to separate the joint, the use of an impact device may
be required on the surface of the boss while under load
from the separator tool. If this method is used and the
knuckle boss is damaged in the process of separating,
jump ahead to the Lower Control Arm and Steering
Knuckle Replacement procedure in SI.
4.4. Remove and discard the lower ball joint nut.
4.5. Clean the upper and lower boss surfaces with
an approved parts cleaner and rag.
4.6. Start by visually inspecting the tapered-hole
edges on both top and bottom surfaces of the
lower boss of the knuckle, looking for
evidence of oblong wear/damage.

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December, 2015

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Bulletin No.: 15-NA-068

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4.7. Next, visually inspect the knuckle’s machined
lower boss face, looking for evidence of
material yielding. Yielding will manifest itself
visually on this surface as a “bubbling”
condition.

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Note: The surface will likely show a uniform pattern of
machining marks across the entire face, which should
NOT be confused with the “bubbling” condition.

4.8. Finally, using a straight edge, check the
flatness of the lower boss surface. Check for
flatness across the boss in at least 5-6
different angular positions about the
centerline of the hole. Look for light passing
between the straight edge and boss surface
to indicate a FAILED straight edge test.
• If the knuckle shows NO evidence of hole
elongation, “bubbling” from yielding, or a
failed straight edge test, as indicated
throughout step 4 above, continue on to
step #5 of this inspection procedure.
• If the knuckle DOES show evidence of hole
elongation, “bubbling” from yielding, or a
failed straight edge test, it will be
necessary to replace the lower control arm
and knuckle. Jump ahead to the Lower
Control Arm and Steering Knuckle
Replacement procedure in SI.
5. Re-seat the ball stud into the tapered hole.

Bulletin No.: 15-NA-068

December, 2015

Page 3

6. Install the NEW lower ball joint nut.

Tighten
• First Pass, 50 Y (37 lb ft)
• Final Pass, plus 120°-135° degrees
7. Reinstall the tire and wheel assembly. Refer to Tire
and Wheel Removal and Installation in SI.

Parts Information
Description

Part Number

Qty

NUT

11546368

1 (As Required)

KNUCKLESTRG (LH)

84036208

1 (As Required)

KNUCKLESTRG (RH)

84036209

1 (As Required)

ARM ASM-FRT
LWR CONT (LH)

23490421

1 (As Required)

ARM ASM-FRT
LWR CONT (RH)

23490422

1 (As Required)

Warranty Information
Labor and the reconfiguration fee associated with these
procedures should NOT be charged under warranty.
Rather, this should be customer pay.
If one of the above parts gets damaged while
performing the steps related to the inspection, warranty
for part replacement will be covered by GM.

Version

2

Modified

December 1, 2015 – adding step 4.2 under the Service Procedure.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these
technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper
service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a
job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your
vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the
information.

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