Audi Audi S4 1997-2002 Suspension Bolt Torque Specifications & Fastener Values
Audi Audi S4 1997-2002

Audi Audi S4 1997-2002 Suspension Bolt Torque Specifications

Detailed torque specifications for all suspension bolts on the 1997-2002 Audi S4 (B5) chassis. Includes front and rear suspension components.

Updated

Important Information

Safety guidelines and reference information for proper torque application

Quick Reference Guide
ft-lbs → Nm
× 1.356
ft-lbs → kg-m
× 0.138
Nm → ft-lbs
× 0.738
in-lbs → ft-lbs
× 0.083

Common Torque Patterns

Star Pattern

Used for wheels and other circular bolt patterns

Star Pattern torque pattern diagram showing proper bolt tightening sequence
Cross Pattern

Used for gaskets and cover plates

Cross Pattern torque pattern diagram showing proper bolt tightening sequence
Sequential Pattern

Used for head bolts and other critical components

Sequential Pattern torque pattern diagram showing proper bolt tightening sequence

Common Mistakes to Avoid

Over-tightening

Exceeding the specified torque value can stretch or break fasteners, damage threads, or crack components.

Prevention:

Always use a calibrated torque wrench and follow specifications exactly.

Incorrect Torque Sequence

Tightening bolts in the wrong order can cause uneven pressure distribution and potential leaks or damage.

Prevention:

Follow the manufacturer's specified torque sequence pattern.

Dirty Threads

Dirt, rust, or old thread locker can affect torque readings and proper fastener tension.

Prevention:

Clean and inspect all threads before assembly. Use new thread locker if specified.

Reusing TTY Bolts

Torque-to-yield bolts are designed to stretch and must not be reused.

Prevention:

Always replace TTY bolts with new ones. They are single-use only.

Dry vs. Lubricated

Not accounting for whether torque specs are for dry or lubricated fasteners can lead to incorrect tension.

Prevention:

Check if specs are for dry or lubricated threads. Use specified lubricant when required.

Recommended Tools

Torque Wrench (1/4" Drive)

Range: 2-25 ft-lbs
Small fasteners, delicate components

Torque Wrench (3/8" Drive)

Range: 10-100 ft-lbs
Most common automotive fasteners

Torque Wrench (1/2" Drive)

Range: 30-250 ft-lbs
Large fasteners, wheels

Angle Gauge

Torque-to-yield (TTY) bolts

Torque Wrench Care

  • Calibrate annually or after 5,000 clicks
  • Store at lowest setting
  • Keep clean and lubricated

Search Specifications

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Torque Calculator

Convert between different torque units

Front Suspension

This section covers the torque specifications for the front suspension components of a 1997-2002 Audi S4 (B5 chassis). These components are critical for steering, handling, and ride quality.

1

Upper Control Arm to Chassis Bolt

M12 x 1.5
Torque Value
48 ft-lbs (65 N·m)
Important Notes
Secures the upper control arm to the chassis. Proper torque is critical for alignment and stability. Estimated value based on similar B5 chassis vehicles.
2

Upper Control Arm to Spindle Nut

M12 x 1.5
Torque Value
41 ft-lbs (55 N·m)
Important Notes
Connects the upper control arm to the spindle. Ensures proper wheel alignment. Estimated value based on similar B5 chassis vehicles.
3

Lower Control Arm to Chassis Bolt (Front)

M14 x 1.5
Torque Value
66 ft-lbs (90 N·m)
Important Notes
Attaches the front of the lower control arm to the chassis. Crucial for structural integrity. Estimated value based on similar B5 chassis vehicles.
4

Lower Control Arm to Spindle Bolt (Rear)

M12 x 1.5
Torque Value
41 ft-lbs (55 N·m)
Important Notes
Attaches the rear of the lower control arm to the spindle. Important for suspension movement. Estimated value based on similar B5 chassis vehicles.
5

Sway Bar Link to Sway Bar Bolt

M10 x 1.25
Torque Value
22 ft-lbs (30 N·m)
Important Notes
Secures the sway bar link to the sway bar. Proper torque is essential for effective sway bar performance. Estimated value based on similar B5 chassis vehicles.
6

Sway Bar Link to Strut Bolt

M10 x 1.25
Torque Value
22 ft-lbs (30 N·m)
Important Notes
Secures the sway bar link to the strut assembly. Estimated value based on similar B5 chassis vehicles.
7

Strut to Spindle Nut (Top)

M14 x 1.5
Important Notes
Attaches the strut assembly to the spindle. Critical for suspension integrity. *Always replace the nut*. Torque to 44 ft-lbs, then turn an additional 90 degrees. Estimated value based on similar B5 chassis vehicles.
8

Strut to Spindle Bolts (Lower)

M12 x 1.5
Torque Value
74 ft-lbs (100 N·m)
Important Notes
Attaches the lower part of the strut to the spindle. Important for wheel support. Estimated value based on similar B5 chassis vehicles.
9

Strut Mount to Body Bolts

M8 x 1.25
Torque Value
18 ft-lbs (25 N·m)
Important Notes
Secures the strut mount to the body. Use caution to not over-torque. Estimated value based on similar B5 chassis vehicles.
10

Wheel Hub Nut (Axle Nut)

M20 x 1.5
Important Notes
Secures the wheel hub and wheel bearing assembly. Angle torque is essential. *Always use a new nut.* Torque to 148 ft-lbs, then turn an additional 180 degrees. Estimated value based on similar B5 chassis vehicles.

Rear Suspension

This section covers the torque specifications for the rear suspension components of a 1997-2002 Audi S4 (B5 chassis). These components ensure proper rear wheel alignment and handling.

1

Upper Control Arm to Chassis Bolt

M12 x 1.5
Torque Value
48 ft-lbs (65 N·m)
Important Notes
Attaches upper control arms to the chassis. Estimated value based on similar B5 chassis vehicles.
2

Upper Control Arm to Spindle Bolt

M12 x 1.5
Torque Value
41 ft-lbs (55 N·m)
Important Notes
Secures the upper control arm to the rear spindle. Estimated value based on similar B5 chassis vehicles.
3

Lower Control Arm to Chassis Bolt (Front)

M14 x 1.5
Torque Value
66 ft-lbs (90 N·m)
Important Notes
Attaches the front of the lower control arm to the chassis. Estimated value based on similar B5 chassis vehicles.
4

Lower Control Arm to Spindle Bolt (Rear)

M12 x 1.5
Torque Value
41 ft-lbs (55 N·m)
Important Notes
Attaches the rear of the lower control arm to the spindle assembly. Estimated value based on similar B5 chassis vehicles.
5

Toe Control Arm to Chassis Bolt

M12 x 1.5
Torque Value
48 ft-lbs (65 N·m)
Important Notes
Connects the toe control arm to the chassis. Estimated value based on similar B5 chassis vehicles.
6

Toe Control Arm to Spindle Bolt

M12 x 1.5
Torque Value
41 ft-lbs (55 N·m)
Important Notes
Connects the toe control arm to the rear spindle. Estimated value based on similar B5 chassis vehicles.
7

Sway Bar Link to Sway Bar Bolt

M10 x 1.25
Torque Value
22 ft-lbs (30 N·m)
Important Notes
Secures the sway bar link to the sway bar. Estimated value based on similar B5 chassis vehicles.
8

Sway Bar Link to Lower Control Arm Bolt

M10 x 1.25
Torque Value
22 ft-lbs (30 N·m)
Important Notes
Secures the sway bar link to the lower control arm. Estimated value based on similar B5 chassis vehicles.
9

Rear Strut/Shock Absorber Lower Bolt

M12 x 1.5
Torque Value
59 ft-lbs (80 N·m)
Important Notes
Attaches the bottom of the shock absorber/strut to the suspension knuckle. Estimated value based on similar B5 chassis vehicles.
10

Rear Strut/Shock Absorber Upper Bolts

M8 x 1.25
Torque Value
18 ft-lbs (25 N·m)
Important Notes
Secures the upper end of the shock/strut to the chassis. Estimated value based on similar B5 chassis vehicles.
Page 1 of 2

Troubleshooting Guide

Common issues, diagnostic steps, and prevention guidelines

Common Issues

Bolt stretching, stripped threads, uneven torque patterns

Loose Components

Symptoms:
  • Rattling or vibration noises
  • Visible movement in components
  • Uneven panel gaps
Solutions:
  • Clean threads and mounting surfaces
  • Replace damaged fasteners
  • Apply proper torque in sequence
  • Use thread locker if specified

Stripped Fasteners

Symptoms:
  • Unable to achieve proper torque
  • Fastener spins freely
  • Visible thread damage
Solutions:
  • Use thread repair kit if appropriate
  • Install thread insert (HeliCoil)
  • Replace component if threaded hole is damaged
  • Upgrade to higher grade fastener if recommended

Overtightened Components

Symptoms:
  • Cracked or deformed parts
  • Broken fasteners
  • Compressed gaskets or seals
Solutions:
  • Replace damaged components
  • Use new fasteners
  • Follow proper torque sequence
  • Verify correct torque specifications

Diagnostic Steps

Visual inspection, torque verification, thread assessment

1

Visual Inspection

Inspect the affected area for any visible signs of damage or wear

  • Check for cracks or deformation
  • Look for signs of excessive wear
  • Verify proper fastener installation
2

Torque Verification

Verify the torque applied to the fasteners

  • Check the torque wrench calibration
  • Verify the torque specification
  • Compare the applied torque to the specification
3

Thread Assessment

Assess the condition of the threads

  • Check for signs of thread damage
  • Verify the thread type and size
  • Check for proper thread engagement

Prevention Guidelines

Best practices, maintenance tips, tool care

Best Practices

  • Always follow the recommended torque specification
  • Use the correct type and size of fasteners
  • Verify the torque wrench calibration regularly

Maintenance Tips

  • Regularly inspect the affected area for signs of wear or damage
  • Replace damaged or worn-out components promptly
  • Keep the work area clean and organized

Tool Care

  • Regularly clean and maintain the torque wrench
  • Store the torque wrench in a dry and secure location
  • Verify the torque wrench calibration before each use

Frequently Asked Questions

Find answers to common questions about torque specifications

Q1

Why are correct torque specifications important for suspension bolts?

Proper torque ensures bolts are tight enough to hold components securely but not so tight that they stretch or break. Under-torqued bolts can loosen, leading to suspension failure and unsafe driving conditions. Over-torqued bolts can fail, damage threads, or distort the surrounding components. It is crucial for component longevity and safety. For example, an under-torqued control arm bolt could cause suspension play and premature wear on the bushing, while an over-torqued strut bolt could fail under load leading to a sudden suspension collapse.

Q2

Can I use a generic torque spec if I don't know the specific one?

No, using generic torque specifications is extremely dangerous and strongly discouraged. Suspension components are highly stressed, and each bolt has a specific torque value calculated by engineers to ensure proper function and safety. Using the wrong spec can lead to catastrophic failure of the suspension. A simple generic bolt may have a different class and thread pitch leading to very different torque requirements. Always refer to the specific torque values for your 1997-2002 Audi S4, found in the factory service manual.

Q3

Should I use new bolts when working on suspension components?

It is highly recommended to replace single-use (torque-to-yield) bolts and nuts each time they are loosened. These bolts are designed to stretch slightly when torqued, which helps maintain a secure connection. Reusing them can compromise their integrity and lead to failure. For other non torque-to-yield components, check for thread wear and replace as needed. For example, a torque-to-yield bolt on the lower control arm should always be replaced.

Q4

What is the best way to ensure correct torque?

The most reliable way to achieve correct torque is by using a calibrated torque wrench. It is essential to use a wrench within its calibrated range. Be sure to apply torque in a slow and steady motion. Use a high quality tool, and have it professionally recalibrated regularly to maintain accuracy. Avoid 'guessing' or trying to feel the correct torque, as this can be inaccurate and unsafe. Always follow the manufacturer's torque procedure, which may include multiple steps.

Environmental Considerations

Temperature, humidity, and seasonal effects on torque specifications

Temperature Effects

Includes: High Heat, Cold Weather, Thermal Cycling

Temperature can significantly impact torque values and fastener behavior

Cold Weather

Effects:
  • Increased material brittleness
  • Higher torque required due to thread contraction
  • Reduced thread lubricant effectiveness
Recommendations:
  • Allow components to warm to room temperature when possible
  • Consider using winter-grade thread lubricants
  • Check torque values more frequently during winter months

Hot Weather

Effects:
  • Thermal expansion of components
  • Decreased friction in threads
  • Accelerated lubricant breakdown
Recommendations:
  • Check torque when components are at normal operating temperature
  • Use temperature-resistant thread lockers
  • Consider re-torquing after heat cycles

Humidity and Corrosion

Covers: Rust Prevention, Salt Exposure, Moisture Control

Moisture and corrosion can affect fastener integrity and torque values

High Humidity

Effects:
  • Accelerated corrosion formation
  • Reduced friction coefficient
  • Potential thread seizing
Prevention:
  • Use corrosion-resistant fasteners
  • Apply appropriate anti-seize compounds
  • Maintain proper protective coatings

Salt Exposure

Effects:
  • Rapid corrosion development
  • Thread damage
  • Seized fasteners
Prevention:
  • Regular underbody washing
  • Use of sacrificial anodes where appropriate
  • Application of protective coatings

Seasonal Maintenance

Spring, Summer, Fall, and Winter maintenance schedules

Spring

  • Inspect for winter damage
  • Clean and protect exposed fasteners
  • Check torque on critical components

Summer

  • Monitor heat-affected components
  • Check expansion-related loosening
  • Inspect cooling system mounts

Fall

  • Prepare for winter conditions
  • Apply corrosion protection
  • Verify all fasteners are properly torqued

Winter

  • More frequent inspection of critical fasteners
  • Check for salt damage
  • Monitor suspension component torque

Related Resources

Tools, service procedures, and technical bulletins

Recommended Tools

Torque Wrench (1/2" Drive)

A calibrated torque wrench capable of measuring torque values between 20 Nm and 200 Nm, with 1/2" drive for socket compatibility.

  • Accurate torque measurement
  • Click-type mechanism
  • Reversible ratchet
Learn more

Torque Wrench (3/8" Drive)

A calibrated torque wrench capable of measuring torque values between 10 Nm and 100 Nm, with 3/8" drive for socket compatibility.

  • Accurate torque measurement
  • Click-type mechanism
  • Reversible ratchet
Learn more

Socket Set (Metric)

A comprehensive set of metric sockets, including sizes 13mm, 16mm, 17mm, 18mm, 19mm, 21mm, and 24mm for various suspension bolts and nuts.

  • Durable construction
  • Variety of sizes
  • 6-point design
Learn more

Wrench Set (Metric)

A comprehensive set of metric wrenches, including sizes 13mm, 16mm, 17mm, 18mm, 19mm, 21mm, and 24mm for various suspension bolts and nuts.

  • Durable construction
  • Variety of sizes
  • Combination open and box end
Learn more

Breaker Bar

A long handle bar used to initially loosen stubborn fasteners before using torque wrench.

  • High leverage
  • Durable construction
  • 1/2" or 3/8" Drive
Learn more

Ball Joint Separator

A tool designed for separating ball joints from control arms without damaging the components.

  • Durable construction
  • Universal fit
  • Adjustable jaw
Learn more

Jack Stands

Safety equipment for supporting the vehicle after lifting with a jack.

  • Durable construction
  • Adjustable height
  • Wide base for stability
Learn more

Vehicle Jack

A hydraulic floor jack capable of lifting the vehicle.

  • High lifting capacity
  • Durable construction
  • Swivel casters
Learn more
Service Procedures

Front Upper Control Arm Replacement

Procedure for replacing the front upper control arms, including torque specifications for all related bolts and nuts.

  • Loosen the wheel lug nuts on the side you are servicing.
  • Raise the vehicle using a floor jack and support it securely with jack stands.
  • Remove the wheel.
  • Use a ball joint separator to separate the upper control arm from the steering knuckle.
  • Remove the nut and bolt securing the upper control arm to the frame.
  • Remove the control arm.
  • Install the new upper control arm. Torque the frame mount nut to 70 Nm. Torque the steering knuckle ball joint nut to 40 Nm + 90 deg.
  • Reinstall the wheel and lower the vehicle.
  • Tighten the lug nuts to the specified torque (120 Nm).
View full procedure

Front Lower Control Arm Replacement

Procedure for replacing the front lower control arms, including torque specifications for all related bolts and nuts.

  • Loosen the wheel lug nuts on the side you are servicing.
  • Raise the vehicle using a floor jack and support it securely with jack stands.
  • Remove the wheel.
  • Use a ball joint separator to separate the lower control arm from the steering knuckle.
  • Remove the nut and bolt securing the lower control arm to the frame.
  • Remove the control arm.
  • Install the new lower control arm. Torque the frame mount nut to 70 Nm + 90 deg. Torque the steering knuckle ball joint nut to 40 Nm + 90 deg.
  • Reinstall the wheel and lower the vehicle.
  • Tighten the lug nuts to the specified torque (120 Nm).
View full procedure

Front Sway Bar Link Replacement

Procedure for replacing the front sway bar links, including torque specifications for all related bolts and nuts.

  • Loosen the wheel lug nuts on the side you are servicing.
  • Raise the vehicle using a floor jack and support it securely with jack stands.
  • Remove the wheel.
  • Remove the nuts from the top and bottom sway bar links.
  • Remove the link.
  • Install the new sway bar link. Torque the upper and lower nuts to 40 Nm.
  • Reinstall the wheel and lower the vehicle.
  • Tighten the lug nuts to the specified torque (120 Nm).
View full procedure

Rear Upper Control Arm Replacement

Procedure for replacing the rear upper control arms, including torque specifications for all related bolts and nuts.

  • Loosen the wheel lug nuts on the side you are servicing.
  • Raise the vehicle using a floor jack and support it securely with jack stands.
  • Remove the wheel.
  • Remove the nut and bolt securing the upper control arm to the frame.
  • Remove the nut and bolt securing the upper control arm to the knuckle.
  • Remove the control arm.
  • Install the new upper control arm. Torque the frame mount nut to 70 Nm + 90 deg. Torque the knuckle mount nut to 70 Nm + 90 deg.
  • Reinstall the wheel and lower the vehicle.
  • Tighten the lug nuts to the specified torque (120 Nm).
View full procedure

Rear Lower Control Arm Replacement

Procedure for replacing the rear lower control arms, including torque specifications for all related bolts and nuts.

  • Loosen the wheel lug nuts on the side you are servicing.
  • Raise the vehicle using a floor jack and support it securely with jack stands.
  • Remove the wheel.
  • Remove the nut and bolt securing the lower control arm to the frame.
  • Remove the nut and bolt securing the lower control arm to the knuckle.
  • Remove the control arm.
  • Install the new lower control arm. Torque the frame mount nut to 70 Nm + 90 deg. Torque the knuckle mount nut to 70 Nm + 90 deg.
  • Reinstall the wheel and lower the vehicle.
  • Tighten the lug nuts to the specified torque (120 Nm).
View full procedure

Rear Sway Bar Link Replacement

Procedure for replacing the rear sway bar links, including torque specifications for all related bolts and nuts.

  • Loosen the wheel lug nuts on the side you are servicing.
  • Raise the vehicle using a floor jack and support it securely with jack stands.
  • Remove the wheel.
  • Remove the nuts from the top and bottom sway bar links.
  • Remove the link.
  • Install the new sway bar link. Torque the upper and lower nuts to 40 Nm.
  • Reinstall the wheel and lower the vehicle.
  • Tighten the lug nuts to the specified torque (120 Nm).
View full procedure
Technical Service Bulletins

Creaking Noise from Front Suspension

2000-05-15

Some vehicles may experience a creaking noise from the front suspension, especially during low-speed maneuvers and over bumps.

1997-2001 Audi S4

Resolution: Inspect and re-torque the front control arm bolts to the specified torque. Additionally, check for wear or damage to the control arm bushings and replace if necessary. Apply anti-seize to bolt threads.

Rear Suspension Noise During Acceleration

2001-11-20

Some Audi S4 models may exhibit a clicking or clunking noise from the rear suspension during acceleration or deceleration.

1998-2002 Audi S4

Resolution: Inspect and torque the rear subframe bolts to 100 Nm. Also check and ensure proper torque on the rear control arms. Inspect for worn sway bar bushings.

Premature Ball Joint Wear

2002-03-01

Reports of premature ball joint wear on various suspension components.

1997-2002 Audi S4

Resolution: Inspect all ball joints for play or excessive wear. Replace with new units and ensure proper torque of ball joint and control arm fasteners. Use proper tools when performing suspension service to avoid damaging components.

About the Author

Expert automotive knowledge and experience

Alan Montanye - Automotive Technical Specialist
ASE

Alan Montanye

Automotive Technical Specialist

ASE Master Certified Technician with over a decade of hands-on experience in automotive repair and diagnostics.

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Technical Information
  • All specifications, including torque values, fluid capacities, and maintenance procedures, should be verified against your vehicle's factory service manual.
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