Body/Frame - Cab Drone or Vibration
Article No. 85-9-43VIBRATION - CAB DRONE OR VIBRATION INDUCED BY EXHAUST SYSTEM (4.9L)
LIGHT TRUCK 1983-1985 F SERIES
A cab drone or vibration at 55 to 65 MPH, may be induced by exhaust system.
1. Neutralize the exhaust system as follows: Loosen all hangers and reposition, as required, so that they hang free and straight. Loosen the flange at the exhaust manifold. Start the engine. Shift to DRIVE, while idling, and back to NEUTRAL. Tighten all hanger bolts, and exhaust system connections (assuring that the exhaust manifold connection is tightened last). Verify exhaust system clearance to chassis.
Figure 42HANGER BRACKET EDTZ-5A246-B MODIFICATION AND INSTALLATION 1984/85 F SERIES 4.9 LITER ENGINES:
2. If condition still exists, remove the intermediate exhaust hanger assembly, located at the rear of the catalytic converter (refer to Figure 42).
^ If improvement is noted, install a new exhaust hanger bracket assembly E0TZ-5A246-B (1983 models only, no bracket or frame hole modification required). Tighten fasteners.
Figure 43 - Frame Drilling Dimensions:
^ For 1984 and 1985 models that show improvement, modify the bracket, and drill the frame as shown in Figure 43.
3. Install the modified bracket assembly, and tighten fasteners, end of procedure.
PART NUMBER PART NAME CLASS
E0TZ-5A246-B Exhaust Hanger C
OTHER APPLICABLE ARTICLES: None
WARRANTY STATUS: Reimbursable within the provisions of the Warranty and Policy Manual.
OPERATION: SP5242A85 - Neutralize Exh. Sys.
TIME: 0.7 Hr.
OPERATION: SP5242A185 Install New Exh. Hanger Assembly
TIME: 0.3 Hr. OPERATION SP5242A285 - Install Modified Bracket Assembly
TIME: 0.6 Hr. DLR. CODING: Basic Part No. 5A246 - Code: 36