Vanden Plas L6-4.0L (1990)
Technical Service Bulletin # 6613
Date: 901201
Rear Suspension - Knock or Sag
REAR SUSPENSION-
SECTION: 66
ELIMINATE KNOCK WITH NEW
No: 13
RIDE LEVEL SENSOR
88-90 MY
Model:
SEDAN RANGE Date: DECEMBER, 1990
KEY POINTS:
STRUT KNOCK REPAIR
ISSUE:
Rear suspension knock or rear end sag can be caused by pressure loss between the valve block and the rear struts.
ACTION:
A new ride level sensor was introduced at VIN 617978. This sensor automatically cycles the ride levelling system when the ignition is switched on,
pressurizing the rear struts if the engine is running. This sensor may be installed on Sedan Range vehicles from 1988 MY through VIN 617977 using the
following procedure:
NOTE:
This repair will correct rear strut knocking and sag caused by pressure loss. Do not replace other ride levelling system components unless
further testing indicates they are at fault.
CAUTION:
On 1988/1989 MY Sedans:
^
The power hydraulic high pressure hose (CCC 2637) MUST be installed as part of recall campaign D348. The part number is stamped on the
aluminum band wrapped around the hose (refer to Administration Bulletin section Recall, number 5).
FIG. 1
^
The pressure relief valve in the solenoid valve block MUST be replaced with a revised valve (CCC 3832) using Service Tool JD 176. (See step 1
of installation).
On 1990 MY Sedans:
^
The high pressure hydraulic hose part number CCC 2625 must be installed. The part number is stamped on the aluminum band wrapped around
the hose. This hose was introduced at VIN 614000.
Installation Procedure:
NOTE:
For 88/89 MY vehicles, do steps 1 and 2. For 1990 MY vehicles, do step 2 only.
CAUTION:
Extreme care must be taken to prevent system contamination. Do not allow any dirt or other debris to enter hoses or the valve block
assembly during these operations.
Step 1: Replacement of Pressure Relief Valve (1988/89 MY vehicles):
Determine if hose CCC2637 and a new pressure relief valve has been installed, (fig. 1). If a new valve has been installed, proceed to step. 2. If the valve
has not been replaced, proceed as follows:
