Audi Audi S4 1997-2002 Brake System Bolt Torque Specifications & Fastener Values
Audi Audi S4 1997-2002

Audi Audi S4 1997-2002 Brake System Bolt Torque Specifications

Detailed torque specifications for brake system bolts on the 1997-2002 Audi S4 (B5) including caliper, carrier, rotor and related 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 Calipers

Torque specifications for the front brake caliper assembly of a 1997-2002 Audi S4 (B5 chassis). This includes the caliper guide pins, mounting bracket, and brake line.

1

Caliper Guide Pin Bolts (Front)

M10 x 1.5
Torque Value
22 ft-lbs (30 N·m)
Important Notes
Ensure guide pins are clean and lubricated. Use a suitable caliper pin grease. Critical for proper caliper movement and pad wear.
2

Caliper Mounting Bracket Bolts (Front)

M12 x 1.5
Torque Value
81 ft-lbs (110 N·m)
Important Notes
These bolts attach the caliper bracket to the wheel bearing hub/steering knuckle. Use a cross-tightening pattern. Critical for safety and braking stability.
3

Brake Line Banjo Bolt (Front)

M10 x 1.0
Torque Value
25 ft-lbs (34 N·m)
Important Notes
Always use new copper crush washers on both sides of the banjo fitting. Overtightening can damage the fitting and cause leaks.

Front Rotors

Torque specifications for components related to the front brake rotors.

1

Brake Rotor Set Screw (Front)

M6 x 1.0
Torque Value
7 ft-lbs (10 N·m)
Important Notes
This screw is to hold the rotor during wheel changes. Do not over-tighten. Its main purpose is for ease of rotor and wheel installation.

Front Sensors

Torque specifications for the front wheel speed sensor.

1

Wheel Speed Sensor Bolt (Front)

M6 x 1.0
Torque Value
7 ft-lbs (10 N·m)
Important Notes
Ensures the wheel speed sensor is correctly secured. Do not overtighten as it can damage the sensor.

Rear Calipers

Torque specifications for the rear brake caliper assembly of a 1997-2002 Audi S4 (B5 chassis). This includes the caliper guide pins, mounting bracket, and brake line.

1

Caliper Guide Pin Bolts (Rear)

M8 x 1.25
Torque Value
18 ft-lbs (25 N·m)
Important Notes
Ensure guide pins are clean and lubricated. Use a suitable caliper pin grease. Critical for proper caliper movement and pad wear.
2

Caliper Mounting Bracket Bolts (Rear)

M12 x 1.5
Torque Value
59 ft-lbs (80 N·m)
Important Notes
These bolts secure the rear caliper bracket to the hub carrier/axle housing. Use a cross-tightening pattern. Critical for safety and braking stability.
3

Brake Line Banjo Bolt (Rear)

M10 x 1.0
Torque Value
25 ft-lbs (34 N·m)
Important Notes
Always use new copper crush washers on both sides of the banjo fitting. Overtightening can damage the fitting and cause leaks.

Rear Rotors

Torque specifications for components related to the rear brake rotors.

1

Brake Rotor Set Screw (Rear)

M6 x 1.0
Torque Value
7 ft-lbs (10 N·m)
Important Notes
This screw is to hold the rotor during wheel changes. Do not over-tighten. Its main purpose is for ease of rotor and wheel installation.

Rear Sensors

Torque specifications for the rear wheel speed sensor.

1

Wheel Speed Sensor Bolt (Rear)

M6 x 1.0
Torque Value
7 ft-lbs (10 N·m)
Important Notes
Ensures the wheel speed sensor is correctly secured. Do not overtighten as it can damage the sensor.

Parking Brake

Torque specifications for parking brake system components.

1

Parking Brake Cable Bracket Bolt

M8 x 1.25
Torque Value
18 ft-lbs (25 N·m)
Important Notes
Secures the parking brake cable bracket to the rear suspension or body. Estimated value based on similar applications.
2

Parking Brake Lever Bolts

M8 x 1.25
Torque Value
15 ft-lbs (20 N·m)
Important Notes
Bolts that connect to the parking brake lever. Estimated value based on similar applications.

Master Cylinder Booster

Torque specifications for the brake master cylinder and booster mounting components.

1

Brake Master Cylinder Mounting Bolts

M8 x 1.25
Torque Value
18 ft-lbs (25 N·m)
Important Notes
These bolts secure the master cylinder to the brake booster. Critical for safety.
2

Brake Booster Mounting Bolts

M8 x 1.25
Torque Value
18 ft-lbs (25 N·m)
Important Notes
These bolts secure the brake booster to the firewall. Correct torque is vital for a secure brake system.

Bleeder Screws

Torque specification for brake bleeder screws.

1

Brake Bleeder Screw

M7 x 1.0
Torque Value
8 ft-lbs (11 N·m)
Important Notes
Hand tighten plus snug. Do not over tighten bleeder screws as they can be easily damaged. Ensure bleeder screws are not rusted or damaged before use.

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 so important for brake bolts?

Using the correct torque ensures that brake components are securely fastened without being over-tightened, which can damage threads, warp rotors, or cause bolt failure. Under-tightening can lead to parts loosening, causing brake failure. Precise torque ensures the consistent clamping force needed for effective and safe braking.

Q2

What happens if I overtighten brake caliper bolts?

Overtightening can stretch or shear bolts, potentially leading to them breaking while driving. It can also warp the caliper mounting surfaces, causing uneven brake pad wear and inconsistent braking performance. In extreme cases, overtightening can also lead to thread damage in the hub or caliper carrier, requiring costly repairs.

Q3

What happens if I undertighten brake caliper bolts?

Undertightening brake bolts can allow the caliper to shift during braking, causing uneven wear of pads, noisy brakes, and reduced braking power. In severe cases, the caliper could detach entirely, leading to catastrophic brake failure. Always double check your work.

Q4

Should I use threadlocker on brake bolts?

It is generally recommended to use a medium-strength threadlocker (like Loctite 242 or similar) on most brake caliper bolts. This helps prevent them from loosening due to vibrations and heat cycling. Always follow the vehicle manufacturer's specifications, and never use high-strength threadlocker on bolts you will need to remove regularly. Clean all threads of oil and grime before application.

Q5

How often should I check the torque on my brake bolts?

It's a good practice to recheck the torque on your brake bolts after the first 50-100 miles after installation, and then every 6 months or during each tire rotation. This will help ensure they remain at their proper specification. If you do any track driving, check them before each event.

Q6

Can I reuse brake bolts?

Generally, it's recommended to replace brake caliper bolts whenever they're removed, especially if they are stretch bolts or if the vehicle has seen hard use like track driving. These bolts are designed for one-time use to maintain specific clamping forces. However, re-using fasteners can sometimes be done if the bolt is in good condition and the thread is not compromised, but this requires careful inspection.

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 is essential for achieving correct bolt torque, preventing over-tightening or under-tightening.

  • 1/2" Drive
  • Calibrated in ft-lbs or Nm
  • Range capable of handling 10-150 ft-lbs (13-203 Nm)
Learn more

Torque Wrench (3/8" drive)

A smaller torque wrench useful for lower torque applications

  • 3/8" Drive
  • Calibrated in ft-lbs or Nm
  • Range capable of handling 5-80 ft-lbs (7-108 Nm)
Learn more

Socket Set (Metric)

A set of metric sockets of various sizes to match the brake caliper and component bolts.

  • 6-point sockets preferred
  • Sizes ranging from 10mm to 21mm
  • Various drive sizes (1/2" and 3/8")
Learn more

Brake Caliper Socket

A specialized socket for specific brake caliper bolts, typically with a hex or spline shape.

  • Size appropriate for caliper bolts
  • May be a hex, triple square (XZN), or spline design
  • Durable construction
Learn more
Service Procedures

Front Brake Caliper Removal and Installation

Procedure for removing and reinstalling the front brake calipers, including tightening to the correct torque specifications.

  • Loosen lug nuts and raise the vehicle on jack stands.
  • Remove wheels.
  • Disconnect brake pad wear sensor (if equipped).
  • Remove the brake line from the caliper.
  • Remove the caliper mounting bolts.
  • Remove the caliper from the rotor, being careful to support the caliper and not stress the brake line.
  • Install the caliper using new bolts. Tighten to 81 ft-lbs (110 Nm) for the 16mm bolts or 63 ft-lbs (85 Nm) for the 14mm bolts.
  • Connect the brake line to the caliper. Tighten to 22 ft-lbs (30 Nm).
  • Connect the brake pad wear sensor (if equipped).
  • Reinstall wheels and lower the vehicle. Tighten lug nuts to 89 ft-lbs (120 Nm).
  • Bleed the brakes.
View full procedure

Rear Brake Caliper Removal and Installation

Procedure for removing and reinstalling the rear brake calipers, including tightening to the correct torque specifications.

  • Loosen lug nuts and raise the vehicle on jack stands.
  • Remove wheels.
  • Disconnect brake pad wear sensor (if equipped).
  • Disconnect the parking brake cable from the caliper.
  • Remove the brake line from the caliper.
  • Remove the caliper mounting bolts.
  • Remove the caliper from the rotor, being careful to support the caliper and not stress the brake line.
  • Install the caliper using new bolts. Tighten to 44 ft-lbs (60 Nm) for the 12mm bolts.
  • Connect the brake line to the caliper. Tighten to 22 ft-lbs (30 Nm).
  • Connect the parking brake cable to the caliper.
  • Connect the brake pad wear sensor (if equipped).
  • Reinstall wheels and lower the vehicle. Tighten lug nuts to 89 ft-lbs (120 Nm).
  • Bleed the brakes.
View full procedure

Brake Rotor Replacement

Procedure for replacing the front and rear brake rotors, including relevant torque specifications.

  • Remove calipers as per instructions above
  • Remove the retaining screw securing the rotor to the hub. If original, this may require a penetrating solvent. If new, it will be 8mm, 10Nm.
  • Remove the old rotor.
  • Install the new rotor, making sure it seats flush against the hub.
  • Reinstall the retaining screw to 10Nm
  • Reinstall calipers using torque values described previously.
  • Reinstall wheels and lower the vehicle. Tighten lug nuts to 89 ft-lbs (120 Nm).
View full procedure
Technical Service Bulletins

Brake Caliper Bolt Corrosion Issues

2001-05-15

Certain vehicles may experience corrosion of brake caliper mounting bolts. This can lead to improper clamping force or bolt failure.

1997-2002 Audi S4

Resolution: Inspect caliper bolts for corrosion during maintenance. Replace with OEM specified bolts. Always use new bolts and apply appropriate torque values upon reassembly.

Brake Line Fitting Leakage

2000-11-20

A small number of vehicles have experienced brake line fitting leakage due to improper torquing during assembly. This can result in brake fluid loss and diminished brake performance.

1997-2000 Audi S4

Resolution: Verify that brake line fittings are free from leaks and torqued to the correct specification of 22 ft-lbs (30 Nm). Always use new sealing washers and bleed the brakes after any brake line maintenance.

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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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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