Audi Audi S8 2012-2018 Suspension Bolt Torque Specifications & Fastener Values
Audi Audi S8 2012-2018

Audi Audi S8 2012-2018 Suspension Bolt Torque Specifications

This page provides detailed torque specifications for all suspension bolts on the 2012-2018 Audi S8 (D4) 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

Search by component name, bolt size, or description

Torque Calculator

Convert between different torque units

Front Upper Control Arm

Components relating to the front upper control arm, connecting to the strut tower and spindle.

1

Upper Control Arm to Strut Tower Bolts

M10 x 1.5
Torque Value
44 ft-lbs (60 N·m)
Important Notes
Estimated based on standard M10 bolt in suspension applications. Use a calibrated torque wrench for accuracy. Clean threads before assembly.
2

Upper Control Arm to Spindle/Knuckle Bolt

M12 x 1.5
Important Notes
Torque to 74 ft-lbs (100 N·m), then turn an additional 90 degrees. Always use a new bolt. Clean threads before assembly.

Front Lower Control Arm

Components relating to the front lower control arm, connecting to the subframe and spindle.

1

Lower Control Arm to Subframe Bolts

M14 x 1.5
Important Notes
Torque to 92 ft-lbs (125 N·m), then turn an additional 180 degrees. Always use a new bolt. Clean threads before assembly.
2

Lower Control Arm to Spindle/Knuckle Ball Joint Pinch Bolt

M10 x 1.25
Important Notes
Torque to 30 ft-lbs (40 N·m), then turn an additional 90 degrees. Always use a new bolt. Ensure the ball joint is properly seated.

Front Strut Assembly

Components relating to the front strut/shock absorber assembly and its mounting points.

1

Front Strut/Shock Absorber Upper Mount Bolts

M8 x 1.25
Torque Value
22 ft-lbs (30 N·m)
Important Notes
Estimated based on standard M8 bolt in automotive applications. Clean threads before assembly.
2

Front Strut/Shock Absorber Lower Mounting Bolt

M14 x 1.5
Important Notes
Torque to 92 ft-lbs (125 N·m), then turn an additional 180 degrees. Always use a new bolt. Clean threads before assembly.

Front Stabilizer Bar

Components relating to the front stabilizer bar (sway bar) and its mounting points.

1

Stabilizer Bar (Sway Bar) Link to Strut/Control Arm Bolts

M10 x 1.25
Important Notes
Torque to 30 ft-lbs (40 N·m), then turn an additional 90 degrees. Clean threads before assembly. Ensure the links are properly aligned.
2

Stabilizer Bar (Sway Bar) Bracket Bolts to Subframe

M8 x 1.25
Torque Value
18 ft-lbs (25 N·m)
Important Notes
Estimated based on standard M8 bolt in automotive applications. Ensure bushings are correctly positioned. Clean threads before assembly.

Rear Upper Control Arm

Components relating to the rear upper control arm, connecting to the body and spindle.

1

Upper Control Arm to Body Bolts

M10 x 1.5
Torque Value
44 ft-lbs (60 N·m)
Important Notes
Estimated based on standard M10 bolt in suspension applications. Clean threads before assembly.
2

Upper Control Arm to Spindle/Knuckle Bolt

M12 x 1.5
Important Notes
Torque to 74 ft-lbs (100 N·m), then turn an additional 90 degrees. Always use a new bolt. Clean threads before assembly.

Rear Lower Control Arm

Components relating to the rear lower control arm, connecting to the subframe and spindle.

1

Lower Control Arm to Subframe Bolts

M14 x 1.5
Important Notes
Torque to 92 ft-lbs (125 N·m), then turn an additional 180 degrees. Always use a new bolt. Clean threads before assembly.
2

Lower Control Arm to Spindle/Knuckle Ball Joint Pinch Bolt

M10 x 1.25
Important Notes
Torque to 30 ft-lbs (40 N·m), then turn an additional 90 degrees. Always use a new bolt. Ensure the ball joint is properly seated.

Rear Strut Assembly

Components relating to the rear strut/shock absorber assembly and its mounting points.

1

Rear Strut/Shock Absorber Upper Mount Bolts

M8 x 1.25
Torque Value
22 ft-lbs (30 N·m)
Important Notes
Estimated based on standard M8 bolt in automotive applications. Clean threads before assembly.
2

Rear Strut/Shock Absorber Lower Mounting Bolt

M14 x 1.5
Important Notes
Torque to 92 ft-lbs (125 N·m), then turn an additional 180 degrees. Always use a new bolt. Clean threads before assembly.

Rear Stabilizer Bar

Components relating to the rear stabilizer bar (sway bar) and its mounting points.

1

Stabilizer Bar (Sway Bar) Link to Strut/Control Arm Bolts

M10 x 1.25
Important Notes
Torque to 30 ft-lbs (40 N·m), then turn an additional 90 degrees. Clean threads before assembly. Ensure the links are properly aligned.
2

Stabilizer Bar (Sway Bar) Bracket Bolts to Subframe

M8 x 1.25
Torque Value
18 ft-lbs (25 N·m)
Important Notes
Estimated based on standard M8 bolt in automotive applications. Ensure bushings are correctly positioned. Clean threads before assembly.

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 proper torque specifications important for suspension bolts?

Correct torque is crucial for suspension component integrity and safety. Over-tightening can damage bolts, threads, or components, leading to failure. Under-tightening can cause components to loosen during operation, leading to instability, noise, and potentially dangerous handling. For example, a loose control arm bolt could result in wheel misalignment or, in severe cases, separation.

Q2

What should I do if I suspect a bolt is cross-threaded or damaged?

If you encounter resistance or notice the bolt not threading smoothly, stop immediately. Forcing it can damage the threads on both the bolt and the component. Inspect both thoroughly. Replace any damaged bolts or components immediately. Attempting to reuse damaged hardware is dangerous. It’s often wise to use a thread chaser to clean out damaged threads if they are not severe. If the internal threads are damaged beyond repair, consider replacing the component (e.g., the control arm or subframe).

Q3

Should I use new bolts each time I work on the suspension?

While not always mandatory, it's highly recommended, especially for torque-to-yield (TTY) bolts which stretch upon tightening. Reusing these bolts can lead to improper clamping force and failure. Many suspension bolts on the Audi S8, particularly those related to the subframe and control arms, are TTY. Consult the repair manual. As a general rule, aluminum bolts and bolts with locking compound should be replaced.

Q4

Can I use aftermarket or non-OEM bolts?

While aftermarket bolts may appear similar, they might not have the same material properties, thread pitch, or hardness as OEM bolts. Using non-OEM bolts can lead to improper torque readings or bolt failure due to different specifications, compromising your vehicle's handling and safety. For critical components like suspension, using OEM parts ensures proper fitment and torque application. Using bolts from unknown or suspect manufacturers is a very bad idea.

Q5

How do I identify a torque-to-yield (TTY) bolt?

TTY bolts are designed to stretch when tightened and are often one-time use only. They may have a different appearance, sometimes having a slightly larger head or different markings. It is best to consult a repair manual specific to your car to confirm. Generally, any bolt that the manufacturer specifies to tighten using an angle torque method after an initial torque reading is a TTY bolt. Common examples are driveshaft bolts, control arm bolts, and subframe bolts.

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 inch drive)

Used to apply precise torque to suspension fasteners.

  • Wide torque range
  • Accurate torque readings
Learn more

Torque Wrench (3/8 inch drive)

Used for smaller suspension fasteners that require a lower torque range.

  • Smaller size for tighter areas
  • Accurate torque readings
Learn more

Socket Set (Metric)

A comprehensive set of metric sockets is essential for various suspension bolt sizes.

  • Durable construction
  • Various sizes including hex/Allen sockets
Learn more

Breaker Bar

Provides extra leverage to loosen stubborn fasteners before applying torque.

  • Heavy-duty construction
  • Long handle for increased leverage
Learn more
Service Procedures

Front Upper Control Arm Bolt Torque Procedure

Procedure for tightening the upper control arm bolts on the front suspension.

  • Loosen all upper control arm bolts.
  • Set torque wrench to the specified torque (typically 70Nm + 90 degrees).
  • Tighten the bolts in a star pattern, completing all bolts to the initial torque.
  • Angle tighten each bolt an additional 90 degrees.
  • Recheck torque after a short test drive
View full procedure

Front Lower Control Arm Bolt Torque Procedure

Procedure for tightening the lower control arm bolts on the front suspension.

  • Loosen all lower control arm bolts.
  • Set torque wrench to the specified torque (typically 100Nm + 180 degrees).
  • Tighten the bolts in a star pattern, completing all bolts to the initial torque.
  • Angle tighten each bolt an additional 180 degrees.
  • Recheck torque after a short test drive
View full procedure

Rear Upper Control Arm Bolt Torque Procedure

Procedure for tightening the upper control arm bolts on the rear suspension.

  • Loosen all rear upper control arm bolts.
  • Set torque wrench to the specified torque (typically 70Nm + 90 degrees).
  • Tighten the bolts in a star pattern, completing all bolts to the initial torque.
  • Angle tighten each bolt an additional 90 degrees.
  • Recheck torque after a short test drive
View full procedure

Rear Lower Control Arm Bolt Torque Procedure

Procedure for tightening the lower control arm bolts on the rear suspension.

  • Loosen all rear lower control arm bolts.
  • Set torque wrench to the specified torque (typically 100Nm + 180 degrees).
  • Tighten the bolts in a star pattern, completing all bolts to the initial torque.
  • Angle tighten each bolt an additional 180 degrees.
  • Recheck torque after a short test drive
View full procedure

Front Strut Upper Mounting Bolts Torque Procedure

Procedure for tightening the strut to body mounting bolts

  • Loosen all strut upper mounting bolts.
  • Set torque wrench to the specified torque (typically 60 Nm)
  • Tighten all bolts to the specified torque.
  • Recheck torque after a short test drive.
View full procedure
Technical Service Bulletins

Suspension Bolt Loosening Issue

2015-03-15

Reports of suspension bolts loosening after service, requiring re-torque.

2012-2015 Audi S8

Resolution: Always use new bolts, ensure proper torque and angle is applied as described in the service procedures, re-check torque after a short test drive.

Control Arm Bolt Replacement Guideline

2016-07-22

Clarification on the replacement procedure of control arm bolts for all affected models.

2012-2018 Audi S8

Resolution: Always replace control arm bolts when loosened, do not reuse. Always use the proper torque specification

Updated torque specification for suspension fasteners

2017-11-10

An update to the torque specification for all suspension fasteners, superseding the torque values previously stated. Please refer to workshop manual.

2012-2018 Audi S8

Resolution: Use the most up to date version of the workshop manual and verify correct torque specifications

About the Author

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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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