Frame and Underbody Chevrolet Malibu VI

Fastener Tightening Specifications

Fastener Tightening Specifications

Alignment Checking

Use a measuring tram gage as an accurate method of determining the alignment of the underbody. The tram gage set required to perform the recommended measuring checks must include a vertical pointer capable of reaching 457 mm (18 in).

The following 2 types of measurement may be made using a tram gage

1. Direct point to point measurements
2. Measurements calculated on a horizontal plane (datum line) parallel to the underbody

Dimensions that are measured to gage holes are measured to the center of the holes and flush to the adjacent metal surface unless otherwise specified. It is recommended that the diagonal dimensions be cross body checked on both sides in order to verify the dimensional accuracy of the vehicle underbody. Set vertical pointers equally as needed per your application.

Checking Frame Alignment

The main components of the frame are the side rails and the crossmembers. The rails carry the load. The crossmembers stabilize the rails.

The 5 types of frame misalignment are the following

1. Sag
2. Buckle
3. Diamond
4. Sidesway
5. Twist

A misaligned frame rail may move in the following directions from where the frame rail should be

1. Forward
2. Up
3. Down
4. To the side

The easiest way to inspect the frame alignment is with gauges that are made for this purpose. Detailed instructions are normally supplied with the gauges at the time of purchase. There are no instructions for gauge use in the manual.

Whether you inspect the alignment with or without gauges, park the vehicle on a level section of floor.

Certain conditions call for preliminary inspections before inspecting the frame. Suspension or axle problems may make it appear that the vehicle frame is out of alignment. If an axle has shifted, diamond or sidesway may appear to exist when neither do exist. A weak spring may make the vehicle appear to have a twisted frame.

A visual inspection of the top and the bottom flanges of each rail may reveal the specific area where the sag or the buckle exist. In the case of a sag, wrinkles may appear on the top of the upper flange. The wrinkles are definite evidence of sag. Wrinkles on the bottom of the lower flange are definite evidence of buckle.

Underbody Inspection

1. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/malibu/vi-2003-2006/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Check for obvious deterioration on the floor pan.
3. Check for loose dirt and corrosion around the inside of the floor pan reinforcement member access holes. This is the first indication that corrosion may exist in hidden areas. Perform all repairs before the final cleaning and protective treatment is performed.
4. Using a chisel, ensure that the drain provisions in the floor pan reinforcement members are open. Open the drain holes in the body side panels using a punch and a drift.

Scheme 1

Scheme 2

1. Support the radiator and condenser by looping a rope around each of the two tabs of the condenser and tie the rope around the upper tie bar.
2. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/malibu/vi-2003-2006/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
3. Remove the front wheels. Refer to «Tire and Wheel Removal and Installation»(/chevrolet/malibu/vi-2003-2006/remont/wheel-tire-system/#tires-wheels) in Tires and Wheels.
4. Remove the engine splash shield. Refer to «Radiator Air Baffle and Deflector Replacement - Lower»(/chevrolet/malibu/vi-2003-2006/remont/cooling-fan/#engine-cooling-system) in Engine Cooling.
5. Disconnect the lower radiator support bracket to frame bolts and disengage the alignment feature.
6. Disconnect the stabilizer link from the stabilizer shaft. Refer to «Stabilizer Shaft Link Replacement»(/chevrolet/malibu/vi-2003-2006/remont/suspension-front/#front-suspension-system) in Front Suspension.
7. Disconnect the outer tie rods (3) from the steering knuckles (6). Refer to «Rack and Pinion Outer Tie Rod End Replacement»(/chevrolet/malibu/vi-2003-2006/remont/manual-power-steering/#power-rack-pinion-steering-system) in Power Steering System.
8. Remove the lower control arms. Refer to «Lower Control Arm Replacement»(/chevrolet/malibu/vi-2003-2006/remont/suspension-front/#front-suspension-system) in Front Suspension.
9. Remove the intermediate steering shaft to steering gear pinch bolt.
10. Disconnect the intermediate steering shaft from the steering gear. Note the alignment of the steering shaft to steering gear for installation.
11. Remove the front transmission mount through bolt.
12. Remove the rear transmission mount through bolt.
13. Support the frame assembly with a support fixture.
14. Remove the rear frame to support brace bolts.
15. Remove the frame to body bolts.
16. Lower the cradle from the vehicle.
17. When replacing the frame, remove the following components: Steering gear-Refer to «Power Steering Gear Replacement»(/chevrolet/malibu/vi-2003-2006/remont/manual-power-steering/#power-rack-pinion-steering-system) in Power Steering System. Stabilizer shaft-Refer to «Stabilizer Shaft Replacement»(/chevrolet/malibu/vi-2003-2006/remont/suspension-front/#front-suspension-system) in Front Suspension. Rear transmission mount bracket.

Installation Procedure

1. When replacing the frame, install the following components. Steering gear-Refer to «Power Steering Gear Replacement»(/chevrolet/malibu/vi-2003-2006/remont/manual-power-steering/#power-rack-pinion-steering-system) in Power Steering System. Stabilizer shaft-Refer to «Stabilizer Shaft Replacement»(/chevrolet/malibu/vi-2003-2006/remont/suspension-front/#front-suspension-system) in Front Suspension. Rear transmission mount bracket
2. Raise the cradle to the vehicle.
3. Install the frame to body bolts. Hand tighten only.
4. Install the rear frame support brace to frame and body bolts. Hand tighten only.
5. Using a drift or suitable alignment tool, align the frame to body through the supplied alignment holes in the rear of the frame. Tighten: Tighten the frame to body bolts to 100 N.m (74 lb ft) plus 90 degrees. Tighten the frame support to body bolts to 100 N.m (74 lb ft).
6. Remove the support fixture.
7. Install the lower control arm. Refer «Lower Control Arm Replacement»(/chevrolet/malibu/vi-2003-2006/remont/suspension-front/#front-suspension-system) in Front Suspension.
8. Connect the outer tie rods (3) to the steering knuckle (6). Refer to «Rack and Pinion Outer Tie Rod End Replacement»(/chevrolet/malibu/vi-2003-2006/remont/manual-power-steering/#power-rack-pinion-steering-system) in Power Steering System.
9. Connect the stabilizer link to the stabilizer shaft. Tighten: Tighten the stabilizer link nut to 65 N.m (48 lb ft).
10. Install the rear transmission mount through bolt. Hand tighten only.
11. Install the front transmission mount through bolt. Hand tighten only.
12. Balance and tighten the powertrain mounts. Refer to «Powertrain Mount Balance Procedure - Lower Mount»(/chevrolet/malibu/vi-2003-2006/remont/mechanical/#engine-mechanical-22l-l61__powertrain-mount-balance-procedure-lower) in Engine Mechanical - 2.2L (L61).
13. Connect the intermediate steering shaft to the steering gear. Locate the shaft as previously noted.
14. Install the Intermediate steering shaft pinch bolt. Tighten: Tighten the bolt to 49 N.m (36 lb ft).
15. Connect the lower radiator support bracket to frame bolts using the alignment feature. Tighten: Tighten the radiator support bracket bolts to 60 N.m (44 lb ft).
16. Install the engine splash shields. Refer to «Radiator Air Baffle and Deflector Replacement - Lower»(/chevrolet/malibu/vi-2003-2006/remont/cooling-fan/#engine-cooling-system) in Engine Cooling.
17. Install the front wheels. Refer to «Tire and Wheel Removal and Installation»(/chevrolet/malibu/vi-2003-2006/remont/wheel-tire-system/#tires-wheels) in Tires and Wheels.
18. Lower the vehicle.
19. Remove the radiator and condenser support.

Removal Procedure

1. Install the engine support fixture. Refer to «Engine Support Fixture»(/chevrolet/malibu/vi-2003-2006/remont/mechanical/#engine-mechanical-35l-lx9__engine-support-fixture) in Engine Mechanical - 3.5L (LX9).
2. Support the radiator and condenser by looping a rope around each of the 2 tabs of the condenser and tie the rope around the upper tie bar.
3. Remove the exhaust pipe heat shield and crossover pipe bolts at the front of the engine. Refer to «Exhaust Crossover Pipe Replacement»(/chevrolet/malibu/vi-2003-2006/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
4. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/malibu/vi-2003-2006/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
5. Remove the front wheels. Refer to «Tire and Wheel Removal and Installation»(/chevrolet/malibu/vi-2003-2006/remont/wheel-tire-system/#tires-wheels) in Tires and Wheels.
6. Remove the engine splash shield. Refer to «Radiator Air Baffle and Deflector Replacement - Lower»(/chevrolet/malibu/vi-2003-2006/remont/cooling-fan/#engine-cooling-system) in Engine Cooling.
7. Disconnect the lower radiator support bracket to frame bolts and disengage the alignment feature.
8. Disconnect the stabilizer link from the stabilizer shaft. Refer to «Stabilizer Shaft Link Replacement»(/chevrolet/malibu/vi-2003-2006/remont/suspension-front/#front-suspension-system) in Front Suspension.
9. Disconnect the outer tie rods (3) from the steering knuckles (6). Refer to «Rack and Pinion Outer Tie Rod End Replacement»(/chevrolet/malibu/vi-2003-2006/remont/manual-power-steering/#power-rack-pinion-steering-system) in Power Steering System.
10. Remove the lower control arms from the frame. Refer to «Lower Control Arm Replacement»(/chevrolet/malibu/vi-2003-2006/remont/suspension-front/#front-suspension-system) in Front Suspension. Support the control arms using mechanics wire. DO NOT separate the ball stud from the knuckle.
11. Remove the exhaust crossover pipe lower bolts. Refer to «Exhaust Crossover Pipe Replacement»(/chevrolet/malibu/vi-2003-2006/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
12. Remove the intermediate steering shaft to steering gear pinch bolt.
13. Disconnect the intermediate steering shaft from the steering gear. Note the alignment of the steering shaft to steering gear for installation.
14. Remove the front transmission mount through bolt.
15. Remove the rear transmission mount through bolt.
16. Remove the frame to side transmission mount bolts.
17. Remove the frame to engine mount bolts.
18. Support the frame assembly with a support fixture.
19. Remove the rear frame to support brace bolts.
20. Remove the frame to body bolts.
21. Lower the frame from the vehicle.
22. Disconnect the heated oxygen sensor wiring harness from the retainer at the rear transmission mount.
23. When replacing the frame, remove the following components: Steering gear-Refer to «Power Steering Gear Replacement»(/chevrolet/malibu/vi-2003-2006/remont/manual-power-steering/#power-rack-pinion-steering-system) in Power Steering System. Stabilizer shaft-Refer to «Stabilizer Shaft Replacement»(/chevrolet/malibu/vi-2003-2006/remont/suspension-front/#front-suspension-system) in Front Suspension. Removing rear transmission mount bracket. Refer to «Transmission Mount Replacement - Rear»(/chevrolet/malibu/vi-2003-2006/remont/automatic-trans/#automatic-transaxle-4t40-e4t45-e-introduction-service-replacement) in Automatic Transaxle - 4T40-E/4T45-E.

1. When replacing the frame, install the following components: Steering gear-Refer to «Power Steering Gear Replacement»(/chevrolet/malibu/vi-2003-2006/remont/manual-power-steering/#power-rack-pinion-steering-system) in Power Steering System. Stabilizer shaft-Refer to «Stabilizer Shaft Replacement»(/chevrolet/malibu/vi-2003-2006/remont/suspension-front/#front-suspension-system) in Front Suspension. Install rear transmission mount bracket - Refer to «Transmission Mount Replacement - Rear»(/chevrolet/malibu/vi-2003-2006/remont/automatic-trans/#automatic-transaxle-4t40-e4t45-e-introduction-service-replacement) in Automatic Transaxle - 4T40-E/4T45-E.
2. Raise the frame to the vehicle.
3. Connect the heated oxygen sensor wiring harness on the retainer at the rear transmission mount.
4. Install the frame to body bolts. Hand tighten only.
5. Install the rear frame support brace to frame and body bolts. Hand tighten only.
6. Using a drift or suitable alignment tool, align the frame to body through the supplied alignment holes in the rear of the frame. Tighten: Tighten the frame to body bolts to 100 N.m (74 lb ft) plus 90 degrees. Tighten the frame support to body bolts to 100 N.m (74 lb ft).
7. Remove the support fixture.
8. Install the lower control arms to the frame. Refer «Lower Control Arm Replacement»(/chevrolet/malibu/vi-2003-2006/remont/suspension-front/#front-suspension-system) in Front Suspension.
9. Connect the outer tie rods (3) to the steering knuckles (6). Refer to «Rack and Pinion Outer Tie Rod End Replacement»(/chevrolet/malibu/vi-2003-2006/remont/manual-power-steering/#power-rack-pinion-steering-system) in Power Steering System.
10. Connect the stabilizer link to the stabilizer shaft. Refer to «Stabilizer Shaft Link Replacement»(/chevrolet/malibu/vi-2003-2006/remont/suspension-front/#front-suspension-system) in Front Suspension.
11. Install the frame to engine mount bolts. Tighten: Tighten the bolts to 50 N.m (37 lb ft).
12. Install the frame to side transmission mount bolts. Tighten: Tighten the bolts to 50 N.m (37 lb ft).
13. Install the rear transmission mount through bolt. Tighten: Tighten the bolt to 90 N.m (66 lb ft).
14. Install the front transmission mount through bolt. Tighten: Tighten the bolt to 90 N.m (66 lb ft).
15. Connect the intermediate steering shaft to the steering gear. Locate the shaft as previously noted.
16. Install the intermediate steering shaft pinch bolt. Tighten: Tighten the bolt to 49 N.m (36 lb ft).
17. Install the exhaust crossover pipe lower bolts. Refer to «Exhaust Crossover Pipe Replacement»(/chevrolet/malibu/vi-2003-2006/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
18. Connect the lower radiator support bracket to frame bolts using the alignment feature. Tighten: Tighten the radiator support bracket bolts to 60 N.m (44 lb ft).
19. Install the engine splash shields. Refer to «Radiator Air Baffle and Deflector Replacement - Lower»(/chevrolet/malibu/vi-2003-2006/remont/cooling-fan/#engine-cooling-system) in Engine Cooling.
20. Install the front wheels. Refer to «Tire and Wheel Removal and Installation»(/chevrolet/malibu/vi-2003-2006/remont/wheel-tire-system/#tires-wheels) in Tires and Wheels.
21. Lower the vehicle.
22. Install the exhaust pipe heat shield and crossover pipe bolts at the front of the engine. Refer to «Exhaust Crossover Pipe Replacement»(/chevrolet/malibu/vi-2003-2006/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
23. Remove the powertrain support fixture. Refer to «Engine Support Fixture»(/chevrolet/malibu/vi-2003-2006/remont/mechanical/#engine-mechanical-35l-lx9__engine-support-fixture) in Engine Mechanical - 3.5L (LX9).
24. Remove the radiator and condenser support. Refer to «Radiator Support Bracket Replacement»(/chevrolet/malibu/vi-2003-2006/remont/cooling-fan/#engine-cooling-system) in Engine Cooling.

Tools Required

J-45725 Frame Bushing Installer. See Special Tools and Equipment .

1. Remove the frame. Refer to «Frame Replacement (W/L61)»(/chevrolet/malibu/vi-2003-2006/remont/frames-subframes-crossmembers/#frame-and-underbody) and «Frame Replacement (W/LX9)»(/chevrolet/malibu/vi-2003-2006/remont/frames-subframes-crossmembers/#frame-and-underbody) .
2. Remove cradle bushing with a rubber mallet.

Scheme 3

1. Install clamp J-45725 onto the bushing leaving about an 1/8 inch from the bottom of the bushing. See «Special Tools and Equipment»(/chevrolet/malibu/vi-2003-2006/remont/frames-subframes-crossmembers/#frame-and-underbody) .
2. Align the split of the bushing to the front of the frame.
3. Using J-45725 install the bushing until the entire radius of the bushing is halfway recessed in the cradle. See «Special Tools and Equipment»(/chevrolet/malibu/vi-2003-2006/remont/frames-subframes-crossmembers/#frame-and-underbody) .
4. Remove the J-45725 clamp. See «Special Tools and Equipment»(/chevrolet/malibu/vi-2003-2006/remont/frames-subframes-crossmembers/#frame-and-underbody) .
5. Install the bushing using the J-45725 until the lip of the bushing is fully seated to the bottom of the cradle assembly. See «Special Tools and Equipment»(/chevrolet/malibu/vi-2003-2006/remont/frames-subframes-crossmembers/#frame-and-underbody) .
6. Install the frame. Refer to «Frame Replacement (W/L61)»(/chevrolet/malibu/vi-2003-2006/remont/frames-subframes-crossmembers/#frame-and-underbody) and «Frame Replacement (W/LX9)»(/chevrolet/malibu/vi-2003-2006/remont/frames-subframes-crossmembers/#frame-and-underbody) .

1. Raise the vehicle hood.
2. Remove the nut securing the vibration dampener to the front of the frame.
3. Remove the vibration dampener from the vehicle.

1. Install the vibration dampener to the frame.
2. Install the vibration dampener nut. Tighten: Tighten the nut to 70 N.m (52 lb ft).
3. Close the vehicle hood.

Scheme 4

A datum is an imaginary horizontal plane that runs below and parallel to the vehicle. Height dimensions are calculated at right angles from the datum to the given control or reference points on the underbody.

The company that develops height dimensions determines the location of the datum based on the equipment being used. Therefore, different datum lines are established for the same vehicle. You can add or subtract an equal amount from all height dimensions and create a new datum line for your usage.

Scheme 5

A centerline is an imaginary vertical plane that is perpendicular to the length of the datum plane through the center of the vehicle. The centerline is any line drawn through the center of the vehicle's datum. The symbol for centerline is CL.

Length

Centerline length measurements are 3-dimensional measurements. The 3 dimensions are the following

1. Length - The distance between 2 points when the height is parallel to the center plane.
2. Height - The measurement is parallel to the datum plane.
3. Width - The measurement is parallel to the center plane.

When reading dimension charts, horizontal width and length dimensions of the underbody are shown as viewed from the bottom of the underbody. Vertical dimensions use the datum plane as a base for all vertical (height) measurements.

Centerline measurements are used with universal measuring equipment.

Scheme 6

The vertical body zero line is an imaginary line drawn through the frame either at the forward or rearward torque box area of the frame.

The front suspension lower control arms are bolted to a suspension support. The front suspension support attaches to the underbody using four bolts. The engine bolts to the integral front side rails. Ensure that the suspension strut towers are dimensionally correct in relation to the remainder of the underbody. This will allow the vehicle to maintain correct caster and camber angles.

The individual underbody components contribute directly to the overall strength of the body. Ensure that you use the proper welding techniques. Properly seal and rustproof the underbody components under the following conditions

1. Whenever the body repair operations destroy or damage the original sealing
2. Whenever the body repair operations destroy or damage the rustproofing

When rustproofing critical underbody components, use a good quality type of air dry primer such as corrosion resistant chromate, or an equivalent material. Do not use combination type primer surfacers.

Special Tools

Special Tools Illustration Tool Number/ Description J-45725 Frame Bushing Installer

See also:
• Lifting and Jacking the Vehicle
• Tire and Wheel Removal and Installation
• Radiator Air Baffle and Deflector Replacement - Lower
• Stabilizer Shaft Link Replacement
• Rack and Pinion Outer Tie Rod End Replacement
• Fastener Notice
• Powertrain Mount Balance Procedure - Lower Mount
• Engine Support Fixture
• Exhaust Crossover Pipe Replacement
• Transmission Mount Replacement - Rear
• Special Tools and Equipment