Frame - Knocking/Pinging Sound
No: 76/23/99/NASRef:
Issue: 1
Date: 09/03/99
Knocking Sound from Vehicle Frame
AFFECTED VEHICLE RANGE:
DISCOVERY Series II (LT) All
SITUATION:
CHASSIS SPACERS PRODUCE NOISE
After a vehicle has been driven for a short period, cornering forces or slow wheel articulation can trigger a knock or "pinging" sound. The noise generally sounds like it originates from the frame in the rear of the vehicle. The sound can sometimes be duplicated by rocking the car.
RESOLUTION:
WELD INTERNAL "SCROLL PLATE" SPACER TO SIDE RAIL
In response to a customer complaint, locate the spacers causing the noise. Drill holes to access the spacer and "puddle weld" the spacer to the frame rails. Dress the weld area and apply paint and undercoating to protect the welded area.
PARTS INFORMATION:
Locally Sourced:
^ Weld-thru coating (3M # 5913, SEM # 39283, or equivalent)
^ Rustoleum "Hard Hat" coating process
Adhesive Primer # 2102
Zinc Spray (Galva) # 2185
Flat Black Top Coat # 2178
Alternate coating material
^ Satin Black "Marhyde" # 3811
TOOLS
MIG Welding equipment
3 mm (1/8 inch) drill bit
8 mm (5/16 inch) drill bit
Automatic Center Punch
Home-made feeler gauge (see procedure)
WARRANTY CLAIMS:
76.10.89164 Time 0.65 hrs. per scroll plate
Weld "scroll plate" spacers to chassis rail
$3.00 Material Allowance
FAULT CODE: K
Normal warranty policy and procedures apply
REPAIR PROCEDURE
CAUTION:
The following procedure requires welding of the frame rails. A qualified welder must perform the repairs.
DRILL WELD LOCATION POINTS
1. Disconnect the battery and ensure that no electronic components will be affected by the welding process.
2. Place the vehicle on a lift and raise to a height where frame side rails are at eye level.
3. Locate inspection holes beneath the rear body mount location (Figures 1 and 2).
4. Fabricate a feeler gauge for drill location measurement as follows:
^ Cut approximately 150 mm (6 in.) of coat hanger or other stiff wire.
^ Select a small 0-ring that fits snugly onto the wire.
^ Slide the 0-ring onto the wire.
CAUTION:
Care must be exercised to avoid bending the arms of the feeler tool.
5. Locate drill points as follows:
^ Insert one end of the feeler wire into the frame rail hole, angled slightly upward, until contact is made with the scroll plate.
^ Position the 0-ring to the edge of the hole.
^ Mark the 0-ring center location and the bottom position of the feeler wire.
^ Withdraw the feeler and position along the marks.
^ Mark the position of the wire end with the center punch.
^ Insert the feeler gauge into the frame rail in the opposite direction.
^ Repeat the measurement at 90 degrees to the original and mark that location with the center punch.
6. Go to step 4 and repeat the measuring process on the inside of the frame rail so that four drill locations are marked.
WELD SCROLL PLATE AND PROTECT FROM CORROSION
1. Drill a 3 mm (1/8 in.) pilot hole at each marked location to ensure that proper location has been achieved.
2. When correct location is verified, drill 8 mm (5/16 in.) holes through frame rails.
3. Apply Weld-thru coating.
4. Puddle weld spacer to frame rail in all four locations.
5. Grind excess weld material flush with frame rail.
6. Paint frame rail internally and externally using Rustoleum paints or Mar-hyde.
7. Connect battery.