Suspension/Alignment - Vehicle Pull Diagnosis: Overview

NUMBER: 02-16-99

GROUP: Suspension

DATE: Dec. 31, 1999

THIS BULLETIN SUPERSEDES TECHNICAL SERVICE BULLETIN 02-03-98 DATED MAY 29, 1998 WHICH SHOULD BE REMOVED FROM YOUR FILES AND NOTED IN THE 1998 TECHNICAL SERVICE BULLETIN MANUAL (PUBLICATION NO. 81-699-99003). THIS IS A COMPLETE REVISION AND NO ASTERISKS HAVE BEEN USED TO HIGHLIGHT THE CHANGES.

SUBJECT:
Vehicle Leads or Pulls

OVERVIEW:
This bulletin covers the diagnosis and repair information for LH vehicles that have a constant pull or lead condition.

MODELS:
1993 - 2000 (LH) Concorde/Intrepid/LHS/New Yorker/Vision

SYMPTOM/CONDITION:
Vehicle has a constant lead or pull on a flat non-crowned road.

DIAGNOSIS:
To assure correct diagnosis, it is important to follow the steps outlined below in the order shown. Road test the vehicle before and after each step to verify that the lead condition has been corrected. When evaluating a vehicle, always drive the same road in both directions to get a feel for the effect of road crown and cross wind. A neutral vehicle will exhibit a small amount of drift on both right and left crowned roads (normal crown sensitivity). A vehicle with pronounced lead/pull may have one or more of the following conditions:

ROOT CAUSE/CORRECTIVE ACTIONS FOR VEHICLE LEAD

1. UNEQUAL TIRE PRESSURE
Adjust tire pressure to the pressure stated on door placard. Make sure the tire pressure is equal on all four tires and evaluate the car. Also note that the tire size and type are correct and match each other. If the car still has a lead condition go to step 2.

2. TIRE CONICITY
Excessive tire conicity is one of the more frequent causes of vehicle lead. Cross switch the front tires and evaluate the car. If the car still leads in the same direction or gets worse, return the front tires to their original position, and go to step 3.

3. SUSPENSION ALIGNMENT
Check and record the vehicle alignment settings including caster. Non-symmetrical front caster or camber can sometimes cause a lead condition or can be used to fix a lead condition. To bias the front suspension caster and/or camber alignment settings to correct or minimize a lead condition perform the Repair Procedure. If the car still leads after the alignment bias procedure, go to step 4 or 5 accordingly.

4. TORQUE INDUCED LEAD
Torque induced lead on LH vehicles is a condition that is generally noticed at speeds above 30 mph, and usually gets worse with mild to moderate acceleration. To repair a vehicle for torque steer perform the engine mount shim section of the Repair Procedure. If the car still leads and all of the previous steps have been performed, go to step 5.

5. STEERING GEAR VALVE IMBALANCE
Steering gear valve imbalance can sometimes cause a vehicle lead. Although there is no quick lest or measurement that can be performed to verify a good or bad steering gear valve, generally the steering efforts will feel much lighter in the lead direction and heavier in the opposite direction with an unbalanced valve. Replace the steering gear only as a "last resort" to solve the problem. To replace the steering gear follow the procedure in Group 19 of the appropriate service manual,

PARTS REQUIRED:

AR(2) 06505362AA Bolt, Camber Adjustment, Strut Clevis to Knuckle
AR(2) 06505363AA Nut, Camber Adjustment, Strut Clevis to Knuckle Bolt
1 05016901AA Lt. Lower Engine Mount Bracket, 98-99 Model Year
1 05016902AA Rt. Lower Engine Mount Bracket, 98-99 Model Year
AR(2) 05016903AA Shim, Engine Mount to Cradle, 98-99 Model Year
AR(2) 04797441 Shim, Engine Mount to Cradle, 93-97 Model Year

POLICY: Reimbursable within the provisions of the warranty.

TIME ALLOWANCE:

Labor Operation No: 02-00-13-94 A/T Hrs.

FAILURE CODE: P8 - New Part