Audi Audi S4 2003-2008 Suspension Bolt Torque Specifications & Fastener Values
Audi Audi S4 2003-2008

Audi Audi S4 2003-2008 Suspension Bolt Torque Specifications

Detailed torque specifications for all suspension bolts on the 2003-2008 Audi S4 (B6 and B7 chassis). Includes front and rear suspension components, control arms, sway bar links, and strut assembly bolts.

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

Search by component name, bolt size, or description

Torque Calculator

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Front Suspension Upper Control Arms

Torque specifications for bolts associated with the front upper control arms. These are critical for maintaining correct suspension geometry and wheel alignment.

1

Upper Control Arm Bolt (Chassis Side)

M12 x 1.5
Torque Value
59 ft-lbs (80 N·m)
Important Notes
Estimated value based on similar models and bolt size. High stress point, ensure proper torque is achieved.
2

Upper Control Arm Bolt (Knuckle/Upright Side)

M10 x 1.5
Torque Value
41 ft-lbs (55 N·m)
Important Notes
Estimated value based on similar models and bolt size. Critical for wheel stability and steering response.

Front Suspension Lower Control Arms

Torque specifications for bolts associated with the front lower control arms. These are crucial for suspension stability and alignment.

1

Lower Control Arm Bolt (Chassis Side)

M14 x 1.5
Torque Value
74 ft-lbs (100 N·m)
Important Notes
Estimated value based on similar models and bolt size. This is a high stress point, ensure proper torque is achieved.
2

Lower Control Arm Bolt (Knuckle/Upright Side)

M10 x 1.5
Torque Value
41 ft-lbs (55 N·m)
Important Notes
Estimated value based on similar models and bolt size. This bolt is crucial for wheel stability and proper suspension movement.

Front Sway Bar

Torque specifications for bolts related to the front sway bar, including end links and bushing brackets.

1

Sway Bar End Link Bolt (Upper)

M10 x 1.5
Torque Value
18 ft-lbs (25 N·m)
Important Notes
Estimated value based on similar models and industry standards. Important for maintaining sway bar effectiveness.
2

Sway Bar End Link Bolt (Lower)

M10 x 1.5
Torque Value
18 ft-lbs (25 N·m)
Important Notes
Estimated value based on similar models and industry standards. Ensures proper sway bar function.
3

Sway Bar Bushing Bracket Bolts

M10 x 1.5
Torque Value
18 ft-lbs (25 N·m)
Important Notes
Estimated value based on similar models and industry standards. Proper tightening prevents bar movement.

Front Strut Assembly

Torque specifications for bolts associated with the front strut assembly, including top mount and knuckle attachments.

1

Strut Top Mount Bolts (Chassis Side)

M8 x 1.25
Important Notes
Critical torque and angle turn for safe attachment. Use a calibrated torque wrench and an angle gauge.
2

Strut to Knuckle/Upright Bolts

M14 x 1.5
Torque Value
74 ft-lbs (100 N·m)
Important Notes
Estimated value based on similar models and bolt size. Critical for maintaining suspension integrity.

Front Subframe

Torque specifications for the main bolts securing the front subframe to the chassis. These are safety-critical fasteners.

1

Subframe Bolts (Main Chassis)

M14 x 2.0
Important Notes
Safety-critical. Use a calibrated torque wrench and an angle gauge. Tighten bolts in a star pattern.

Steering

Torque specification for the tie rod end lock nut, which is critical for steering stability.

1

Tie Rod End Lock Nut

M14 x 1.5
Torque Value
41 ft-lbs (55 N·m)
Important Notes
Estimated value based on similar models and industry standards. Ensure proper torque for steering stability and alignment.

Rear Suspension Upper Control Arms

Torque specifications for bolts associated with the rear upper control arms, important for rear wheel alignment and suspension movement.

1

Upper Control Arm Bolt (Chassis Side)

M12 x 1.5
Torque Value
59 ft-lbs (80 N·m)
Important Notes
Estimated value based on similar models and bolt size. This is a high stress point, ensure proper torque is achieved.
2

Upper Control Arm Bolt (Knuckle/Upright Side)

M10 x 1.5
Torque Value
41 ft-lbs (55 N·m)
Important Notes
Estimated value based on similar models and bolt size. Critical for stability and steering.

Rear Suspension Lower Control Arms

Torque specifications for bolts associated with the rear lower control arms. Crucial for maintaining proper suspension and alignment.

1

Lower Control Arm Bolt (Chassis Side)

M14 x 1.5
Torque Value
74 ft-lbs (100 N·m)
Important Notes
Estimated value based on similar models and bolt size. High stress point, ensure proper torque is achieved.
2

Lower Control Arm Bolt (Knuckle/Upright Side)

M10 x 1.5
Torque Value
41 ft-lbs (55 N·m)
Important Notes
Estimated value based on similar models and bolt size. Essential for safety and performance.

Rear Sway Bar

Torque specifications for bolts related to the rear sway bar, including end links and bushing brackets.

1

Rear Sway Bar End Link Bolt (Upper/Lower)

M10 x 1.5
Torque Value
18 ft-lbs (25 N·m)
Important Notes
Estimated value based on similar models and industry standards. Ensures correct sway bar function.
2

Rear Sway Bar Bushing Bracket Bolts

M10 x 1.5
Torque Value
18 ft-lbs (25 N·m)
Important Notes
Estimated value based on similar models and industry standards. Correct torque maintains sway bar effectiveness.

Rear Shock Absorbers

Torque specifications for bolts associated with the rear shock absorbers.

1

Shock Absorber Lower Bolt

M14 x 1.5
Torque Value
74 ft-lbs (100 N·m)
Important Notes
Estimated value based on similar models and bolt size. Proper tightening is needed for safe operation.
2

Shock Absorber Upper Mount Bolts (Chassis Side)

M8 x 1.25
Torque Value
30 ft-lbs (40 N·m)
Important Notes
Estimated value based on similar models and bolt size. Essential for safe operation of the shock.

Rear Subframe

Torque specifications for the main bolts securing the rear subframe to the chassis. These are safety-critical fasteners.

1

Rear Subframe Bolts (Main Chassis)

M14 x 2.0
Important Notes
Safety-critical. Use a calibrated torque wrench and an angle gauge. Tighten bolts in a star pattern.

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 is using the correct torque specification so important for suspension bolts?

Using the correct torque specification ensures that the suspension components are properly secured and functioning within design parameters. Under-torquing can lead to bolts loosening over time, causing movement and potential damage or failure. Over-torquing can stretch or weaken bolts, also leading to failure and potentially damaging the threads in components. The suspension is a critical safety system; incorrect torquing can severely compromise vehicle handling and stability.

Q2

What happens if I overtighten a suspension bolt?

Overtightening a suspension bolt can lead to several problems. You risk stretching the bolt beyond its elastic limit, which weakens it and makes it more prone to fatigue and breakage. This can also damage the threads in the receiving component (e.g., control arm or knuckle), potentially requiring costly repairs. You might also crush bushings, causing premature wear and altered suspension performance.

Q3

Can I reuse suspension bolts?

It is generally not recommended to reuse critical suspension bolts, particularly those that are torque-to-yield (TTY) bolts. TTY bolts are designed to stretch during tightening, and reusing them can compromise their clamping force and integrity. These bolts should always be replaced with new ones. Even non-TTY bolts should ideally be replaced when removed as their strength and integrity can be compromised during removal and handling.

Q4

What does 'torque-to-yield' (TTY) mean?

Torque-to-yield (TTY) bolts are designed to stretch slightly when tightened. This stretching is an intentional part of the fastening process. They are tightened to a specific torque and then turned an additional angle. TTY bolts should always be replaced when removed and cannot be reliably reused. Failure to replace TTY bolts could lead to joint failure or reduced safety.

Q5

Do I need to use new nuts and washers with suspension bolts?

Yes, especially with lock nuts and self-locking washers. Lock nuts and some washers are designed to provide extra resistance against loosening and are meant for single use only. Reusing these components may not provide adequate clamping force and may result in bolts loosening due to vibrations. It's a best practice to replace these when replacing bolts as they are cost-effective compared to component replacement after failure.

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

A calibrated torque wrench is essential for accurately tightening suspension bolts to the specified torque values. Both click-type and dial-type wrenches are suitable.

  • Measures torque accurately
  • Adjustable torque settings
Learn more

Socket Set

A comprehensive socket set, including various metric sizes, is required to fit the different bolt heads on the suspension components.

  • Various sizes
  • Metric sizes
Learn more

Wrench Set

A wrench set, including various metric sizes, is required to fit the different bolt heads on the suspension components.

  • Various sizes
  • Metric sizes
Learn more

Extensions

Various socket extensions and universal joints might be needed to reach recessed or awkwardly positioned suspension bolts.

  • Reaches difficult areas
  • Enhances flexibility
Learn more

Jack Stands

Essential for supporting the vehicle safely once lifted, enabling access to suspension components.

  • Safe vehicle support
  • Adjustable height
Learn more

Vehicle Jack

Used to safely raise the vehicle to access the suspension.

  • Lifts vehicles
  • Safe lifting
Learn more
Service Procedures

Front Upper Control Arm Bolt Torque Procedure

This procedure outlines the steps to properly torque the bolts on the front upper control arms of the Audi S4.

  • 1. Loosen, but do not remove, the upper control arm bolts.
  • 2. Position the suspension in normal ride height by using a jack to lift the control arm slightly.
  • 3. Tighten the bolts to 40Nm + 90 degrees.
  • 4. Verify torque using a calibrated torque wrench.
View full procedure

Front Lower Control Arm Bolt Torque Procedure

This procedure outlines the steps to properly torque the bolts on the front lower control arms of the Audi S4.

  • 1. Loosen, but do not remove, the lower control arm bolts.
  • 2. Position the suspension in normal ride height by using a jack to lift the control arm slightly.
  • 3. Tighten the bolts to 70Nm + 90 degrees.
  • 4. Verify torque using a calibrated torque wrench.
View full procedure

Front Stabilizer Bar Link Bolt Torque Procedure

This procedure outlines the steps to properly torque the bolts on the front stabilizer bar links of the Audi S4.

  • 1. Loosen, but do not remove, the stabilizer bar link bolts.
  • 2. Tighten the bolts to 50Nm.
  • 3. Verify torque using a calibrated torque wrench.
View full procedure

Rear Upper Control Arm Bolt Torque Procedure

This procedure outlines the steps to properly torque the bolts on the rear upper control arms of the Audi S4.

  • 1. Loosen, but do not remove, the upper control arm bolts.
  • 2. Position the suspension in normal ride height by using a jack to lift the control arm slightly.
  • 3. Tighten the bolts to 40Nm + 90 degrees.
  • 4. Verify torque using a calibrated torque wrench.
View full procedure

Rear Lower Control Arm Bolt Torque Procedure

This procedure outlines the steps to properly torque the bolts on the rear lower control arms of the Audi S4.

  • 1. Loosen, but do not remove, the lower control arm bolts.
  • 2. Position the suspension in normal ride height by using a jack to lift the control arm slightly.
  • 3. Tighten the bolts to 70Nm + 90 degrees.
  • 4. Verify torque using a calibrated torque wrench.
View full procedure

Rear Stabilizer Bar Link Bolt Torque Procedure

This procedure outlines the steps to properly torque the bolts on the rear stabilizer bar links of the Audi S4.

  • 1. Loosen, but do not remove, the stabilizer bar link bolts.
  • 2. Tighten the bolts to 50Nm.
  • 3. Verify torque using a calibrated torque wrench.
View full procedure

Shock Absorber Mounting Bolt Torque Procedure

This procedure outlines the steps to properly torque the bolts on the shock absorbers of the Audi S4.

  • 1. Loosen, but do not remove, the shock absorber mounting bolts.
  • 2. Tighten the upper bolts to 25Nm + 90 degrees
  • 3. Tighten the lower bolts to 70Nm + 90 degrees
  • 4. Verify torque using a calibrated torque wrench.
View full procedure
Technical Service Bulletins

Suspension Noise After Repair

2007-05-15

Some instances of suspension noises after component replacement may be due to incorrect bolt torquing. Always ensure all fasteners are tightened to manufacturer's specifications.

2003-2008

Resolution: Re-check all suspension bolt torque specifications to ensure they meet the recommended values and that the vehicle is at ride height before final tightening.

Control Arm Bolt Loosening Issue

2005-11-20

Reports indicate some lower control arm bolts are loosening prematurely. The current recommendation is to replace the bolt and use new hardware.

2003-2006

Resolution: When replacing control arms, always use new bolts. Ensure the bolts are torqued correctly, and verify the vehicle is in the normal ride height position before final torque application.

Shock Absorber Bolt Reuse

2006-02-20

It is strongly recommended not to reuse any shock absorber bolts due to potential yield. Use new hardware for every removal/installation.

2003-2008

Resolution: When replacing shock absorbers always replace mounting hardware, Ensure the bolts are torqued correctly, and verify the vehicle is in the normal ride height position before final torque application.

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