Wagoneer L6-242 4.0L VIN L FI (1989)
Jeep
Cherokee
1989
January, 1989
33,000
Vehicles equipped
and
and
through
(Est.)
with anti-lock
Wagoneer
1990
June, 1990
brake system.
Estimated percentage containing defect:
Unknown
Description of defect:
Proper functioning of the Anti-Lock Brake System (ABS) on the involved vehicles may be impaired by two hydraulic fluid contamination conditions:
^
Precipitate formation may plug the ABS brake booster pump filter, initially resultinq in loss of the ABS function. Should this occur, the instrument
panel light will signal ABS impairment, and the base brakes and power assist will remain functional.
^
Chlorine may cause stress corrosion failure of a master cylinder snap ring. A portion of a failed ring, may wedge in the bore and prevent full return
of the piston assembly,resulting in brake drag.
Events which were the basis for determining existence of defect:
Field reports of ABS malfunction were received by Chrysler. Subsequent investigation and analysis of returned parts revealed that the malfunctions were
the result of two separate system contamination issues:
^
The combination of a releasing aqent (zinc-stearate) used during manufacture of the system's low pressure hose and a silicone grease used as an
assembly aid formed a precipitate that could plug the ABS pump filter.
^
Stress corrosion of a master cylinder snap ring has been traced to chlorine leaching from the low pressure hose.
Based on the potential consequences of these conditions, Chrysler has determined that field corrective action is required.
Statement of measures to be taken to correct defect:
All involved vehicles will have the ABS low pressure hose replaced with a hose of a different material and the master cylinder will be rebuilt with new
piston assemblies containing a thicker snap ring.
In addition, the low frequency potential for front brake hose to tire interference on the involved vehicles will also be addressed. All vehicles will be
inspected and serviced as necessary to eliminate any potential for hose interference and resultant damage.
Dealer Instructions
IMPORTANT
DEALER INSTRUCTIONS
SAFETY RECALL # 305T -
ANTI-LOCK BRAKE SYSTEM AND FRONT BRAKE HOSES
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This service requirement applies only to 1989 and 1990 Model Year XJ - Jeep Cherokee and Wagoneer - vehicles equipped with anti-lock brake
systems.
^
The following steps are required for service of the anti-lock brake system (ABS):
-
Remove hydraulic unit from vehicle.
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Replace low pressure supply hose.
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Remove piston assemblies from actuator portion of hydraulic unit.
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Clean actuator bore and install new piston assemblies.
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Replace plug and O-ring in switch section of modulator.
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Remove and replace brake fluid reservoir, cap, and modulator return hose.
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Reinstall hydraulic unit.
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Road test vehicle for ABS system function.
^
In addition to the ABS service, both front brake hoses must be inspected for proper routing.
^
For this recall, parts will be shipped and billed to involved dealers in accordance with the newly announced Recall Parts Pricing policy.
A partial guantity of ABS service parts packages will be distributed initially to all involved dealers. As this quantity will be only a portion of the
total parts requirement, dealers must order additional ABS service parts packages as needed to support customer demand.
