Audi Audi A3 2013-2020 Suspension Bolt Torque Specifications & Fastener Values
Audi Audi A3 2013-2020

Audi Audi A3 2013-2020 Suspension Bolt Torque Specifications

Comprehensive guide to suspension bolt torque specifications for the 2013-2020 Audi A3 (8V) chassis. Includes torque values for 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 Suspension Strut

Torque specifications for the front strut assembly and related components.

1

Strut/Shock Absorber Mounting Bolts

M10 x 1.5
Torque Value
33 ft-lbs (45 N·m)
Important Notes
These bolts secure the strut to the strut tower or knuckle. Ensure proper tightening to prevent movement and maintain correct suspension geometry.
2

Strut Top Mount Bolts

M8 x 1.25
Important Notes
These bolts secure the top of the strut to the vehicle body. Torque and angle tightening is required to ensure proper compression of the mount and avoid damage to the vehicle body. Always confirm specific torque specs for your application.
3

Hub/Knuckle to Strut Pinch Bolt

M12 x 1.75
Important Notes
This bolt clamps the steering knuckle around the bottom of the strut. Torque and angle tightening is required to secure the hub and knuckle. Always confirm specific torque specs for your application.

Front Suspension Control Arms

Torque specifications for control arm components.

1

Control Arm Bolts

M12 x 1.5
Torque Value
74 ft-lbs (100 N·m)
Important Notes
These bolts secure the control arm to the frame or subframe and knuckle. Ensure proper torque to maintain suspension integrity and alignment.
2

Control Arm to Subframe Bolts

M12 x 1.5
Torque Value
74 ft-lbs (100 N·m)
Important Notes
These bolts secure the control arm to the subframe. Ensure proper torque to maintain suspension integrity and alignment.
3

Ball Joint Nut

M12 x 1.25
Torque Value
44 ft-lbs (60 N·m)
Important Notes
Secures the ball joint to the control arm or knuckle. Do not over-tighten to avoid damage to the ball joint.

Front Suspension Steering

Torque specifications for front steering components.

1

Tie Rod End Nut

M10 x 1.5
Torque Value
44 ft-lbs (60 N·m)
Important Notes
Secures the tie rod end to the steering knuckle. Correct torque is critical for maintaining proper steering and alignment.

Front Suspension Sway Bar

Torque specifications for the front sway bar components.

1

Sway Bar Link Nut

M8 x 1.25
Torque Value
33 ft-lbs (45 N·m)
Important Notes
Secures the sway bar links to the sway bar and the strut or control arm. Over-tightening can cause binding or damage.
2

Anti-Roll Bar/Sway Bar Bushing Bracket Bolts

M8 x 1.25
Torque Value
18 ft-lbs (25 N·m)
Important Notes
These bolts secure the sway bar bushings to the vehicle's chassis or subframe. Ensure proper torque to allow the sway bar to function properly and prevent damage.

Rear Suspension

Torque specifications for rear suspension components.

1

Rear Trailing Arm Mounting Bolts

M12 x 1.75
Important Notes
For models with independent rear suspension, these bolts are critical for correctly locating the wheels, controlling movement, and supporting the vehicle's weight. Torque and angle tightening is required. Always confirm specific torque specs for your application.

Wheel And Brakes

Torque specifications for wheel and brake components.

1

Wheel Lug Nuts

M14 x 1.5
Torque Value
89 ft-lbs (120 N·m)
Important Notes
Critical for securing the wheel to the hub. Tighten in a star pattern.
2

Brake Caliper Mounting Bracket Bolts

M12 x 1.75
Torque Value
81 ft-lbs (110 N·m)
Important Notes
Secure the caliper bracket to the hub/knuckle assembly. Ensure proper tightening for braking efficiency and safety.
3

Brake Disc/Drum Retaining Bolts

M8 x 1.25
Torque Value
81 ft-lbs (110 N·m)
Important Notes
These bolts secure the brake disc/drum to the hub assembly. Ensure proper torque to prevent vibration, warping, and for the overall safety of the vehicle.

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 important for suspension bolts?

Using the correct torque is crucial for suspension bolt safety and performance. Under-tightening can cause bolts to loosen, leading to component failure, noise, and handling issues. Over-tightening can stretch or break bolts, damaging components and compromising the suspension's integrity. This could cause a catastrophic suspension failure while driving. Proper torque ensures the correct clamping force, preventing movement and maintaining proper suspension geometry. For example, improperly torqued control arm bolts can lead to rapid tire wear and poor handling, while improperly torqued strut bolts can lead to the strut becoming disconnected.

Q2

Should I use new bolts when replacing suspension components?

Yes, it is generally recommended to use new bolts when replacing suspension components, especially stretch bolts. These bolts are designed to stretch slightly when torqued, providing consistent clamping force. Reusing them can compromise their strength and lead to insufficient clamping force. Reusing bolts can cause future failure and should be avoided. An example is the pinch bolt for the lower strut assembly – it is critical that this be replaced with new.

Q3

What tools do I need to properly torque suspension bolts?

You will need a calibrated torque wrench, sockets of the correct size (metric for Audi A3), and potentially extensions or universal joints to access certain bolts. It's vital that the torque wrench is calibrated regularly for accuracy. A torque angle meter may also be required for certain bolts that require torque-to-yield methods. Always refer to the Audi service manual to ensure you use the appropriate method. It may also be helpful to have some penetrating oil to help remove older bolts.

Q4

What are 'torque-to-yield' bolts and how do they differ?

Torque-to-yield (TTY) bolts are designed to stretch upon tightening, achieving precise clamping force. They are typically tightened to a specified torque and then turned an additional angle. These bolts must be replaced after being loosened, as they have been permanently deformed and will not provide proper clamping if reused. Many critical suspension bolts on the Audi A3, like those connecting the subframe, are TTY bolts. Failure to replace them can be very dangerous.

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 with a 1/2" drive is essential for accurately tightening suspension bolts to their specified torque.

  • Accurate torque measurement
  • Audible click mechanism
  • Wide torque range
Learn more

Torque Wrench (3/8" Drive)

A calibrated torque wrench with a 3/8" drive is helpful for accessing hard-to-reach bolts with lower torque specifications.

  • Accurate torque measurement
  • Audible click mechanism
  • Smaller size for tighter spaces
Learn more

Socket Set (Metric)

A comprehensive metric socket set is required to fit the various bolt head sizes used in the suspension system.

  • Various sizes
  • Durable construction
  • 6-point and 12-point options
Learn more

Socket Extensions

Socket extensions of various lengths are necessary to reach bolts in recessed areas of the suspension.

  • Allows access to deep bolts
  • Various lengths available
  • Durable construction
Learn more

Breaker Bar

A breaker bar provides extra leverage to loosen stubborn bolts before torqueing to specification.

  • Increased leverage
  • Durable construction
  • Long handle
Learn more

Jack Stands

Heavy-duty jack stands are crucial for safely supporting the vehicle while working on the suspension.

  • Adjustable height
  • Secure locking mechanism
  • High load capacity
Learn more

Vehicle Jack

A suitable vehicle jack is needed to lift the vehicle to access and work on the suspension components.

  • Safe and stable lift
  • Appropriate load capacity
  • Portable
Learn more
Service Procedures

Front Strut Assembly Bolt Torque Procedure

This procedure details how to properly torque the bolts when servicing the front strut assembly.

  • Lift and safely secure the vehicle using jack and jack stands.
  • Locate the upper strut mount bolts, lower strut-to-knuckle bolts, and sway bar end link connection.
  • Using the correct sockets and torque wrench, tighten upper strut mount bolts to 40 Nm (29.5 ft-lb).
  • Tighten lower strut-to-knuckle bolts to 70 Nm (52 ft-lb) + 90 degrees.
  • Tighten the sway bar end link to 50 Nm (37 ft-lb).
  • Lower the vehicle and perform a visual inspection to confirm proper installation and torque.
View full procedure

Rear Shock Absorber Bolt Torque Procedure

This procedure outlines the proper steps for torquing the bolts when replacing the rear shock absorbers.

  • Lift and safely support the vehicle using jack and jack stands.
  • Locate the upper and lower shock absorber mounting bolts.
  • Using the correct socket and torque wrench, tighten the upper shock bolt to 40 Nm (29.5 ft-lb).
  • Tighten the lower shock bolt to 60 Nm (44 ft-lb) + 90 degrees.
  • Lower the vehicle and perform a final inspection.
View full procedure

Control Arm Bolt Torque Procedure

This procedure explains how to torque the control arm bolts for both the front and rear suspension.

  • Lift and safely secure the vehicle using jack and jack stands.
  • Locate the control arm mounting bolts for the desired suspension.
  • For the front suspension, tighten inner control arm bolts to 70 Nm (52 ft-lb) + 90 degrees and outer control arm bolts to 40 Nm (29.5 ft-lb) + 90 degrees.
  • For the rear suspension, tighten the lower control arm bolts to 70 Nm (52 ft-lb) + 90 degrees and upper control arm bolts to 70 Nm (52 ft-lb).
  • Lower the vehicle and perform a visual inspection to confirm proper installation and torque.
View full procedure
Technical Service Bulletins

Front Suspension Creaking Noise

2018-07-15

A creaking noise from the front suspension may be caused by loose or improperly torqued strut bolts.

2013-2017

Resolution: Inspect and re-torque the upper strut mount bolts, lower strut-to-knuckle bolts and sway bar end link connection to the manufacturer's specified torque values. Replacement of the strut mount may be necessary if creaking persists.

Rear Suspension Thumping Noise

2019-02-28

A thumping noise from the rear suspension may be caused by loose or improperly torqued shock absorber bolts.

2015-2020

Resolution: Inspect and re-torque the upper and lower shock absorber bolts to the manufacturer's specified torque values. If thumping persists replace the shock absorbers.

Premature Control Arm Bushing Wear

2020-11-10

Premature wear of control arm bushings can sometimes be related to improper torque during installation or previous repairs.

2013-2020

Resolution: Verify the control arm mounting bolts have been torqued to the manufacturer's specified torque values. Replace any worn control arm bushings and ensure bolts are re-torqued to spec after replacement.

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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