Audi Audi A4 2017-present Suspension Bolt Torque Specifications
Comprehensive list of torque specifications for suspension bolts on the 2017-Present Audi A4 (B9) chassis. Includes front and rear suspension components.
Important Information
Safety guidelines and reference information for proper torque application
Safety First
- Always verify torque specifications with your vehicle's factory service manual
- Use properly calibrated torque wrenches
- Replace all torque-to-yield (TTY) bolts - they are single-use only
- When in doubt, consult a professional mechanic
Quick Reference Guide
Quick Reference Guide
Common Torque Patterns
Star Pattern
Used for wheels and other circular bolt patterns
Cross Pattern
Used for gaskets and cover plates
Sequential Pattern
Used for head bolts and other critical components
Common Mistakes to Avoid
Common Mistakes to Avoid
Over-tightening
Exceeding the specified torque value can stretch or break fasteners, damage threads, or crack components.
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.
Follow the manufacturer's specified torque sequence pattern.
Dirty Threads
Dirt, rust, or old thread locker can affect torque readings and proper fastener tension.
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.
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.
Check if specs are for dry or lubricated threads. Use specified lubricant when required.
Recommended Tools
Recommended Tools
Torque Wrench (1/4" Drive)
Torque Wrench (3/8" Drive)
Torque Wrench (1/2" Drive)
Angle Gauge
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
Torque specifications for the front suspension components of a 2017-Present Audi A4.
1 Strut/Shock Absorber Upper Mounting Bolts
M10 x 1.5
Strut/Shock Absorber Upper Mounting Bolts
M10 x 1.5Torque Value
Important Notes
2 Strut/Shock Absorber Lower Mounting Bolts
M12 x 1.5
Strut/Shock Absorber Lower Mounting Bolts
M12 x 1.5Torque Value
Important Notes
3 Control Arm Bolts (Frame/Subframe)
M14 x 1.5
Control Arm Bolts (Frame/Subframe)
M14 x 1.5Torque Value
Important Notes
4 Control Arm Bolts (Spindle/Steering Knuckle)
M12 x 1.5
Control Arm Bolts (Spindle/Steering Knuckle)
M12 x 1.5Torque Value
Important Notes
5 Ball Joint Nut
M12 x 1.25
Ball Joint Nut
M12 x 1.25Torque Value
Important Notes
6 Tie Rod End Nut
M10 x 1.25
Tie Rod End Nut
M10 x 1.25Torque Value
Important Notes
7 Sway Bar Link Nut
M8 x 1.25
Sway Bar Link Nut
M8 x 1.25Torque Value
Important Notes
8 Steering Knuckle to Strut Bolts
M12 x 1.5
Steering Knuckle to Strut Bolts
M12 x 1.5Important Notes
9 Upper Control Arm to Frame Bolts
M12 x 1.5
Upper Control Arm to Frame Bolts
M12 x 1.5Torque Value
Important Notes
Rear Suspension
Torque specifications for the rear suspension components of a 2017-Present Audi A4.
1 Rear Trailing Arm Bolts
M14 x 1.5
Rear Trailing Arm Bolts
M14 x 1.5Torque Value
Important Notes
2 Rear Shock/Strut Lower Mount Bolt
M12 x 1.5
Rear Shock/Strut Lower Mount Bolt
M12 x 1.5Torque Value
Important Notes
Chassis And Subframe
Torque specifications for chassis and subframe components of a 2017-Present Audi A4.
1 Subframe Bolts
M14 x 1.5
Subframe Bolts
M14 x 1.5Important Notes
2 Sway Bar Bracket Bolts
M8 x 1.25
Sway Bar Bracket Bolts
M8 x 1.25Torque Value
Important Notes
Troubleshooting Guide
Common issues, diagnostic steps, and prevention guidelines
Common Issues
Bolt stretching, stripped threads, uneven torque patterns
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
Diagnostic Steps
Visual inspection, torque verification, thread assessment
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
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
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
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?
Why are proper torque specifications important for suspension bolts?
Proper torque is crucial for suspension bolt integrity. Under-tightening can lead to loosening, component movement, and potential failure, creating unsafe driving conditions and damaging the suspension components. Over-tightening can stretch bolts, damage threads, or even cause the bolt to break. Both scenarios can result in costly repairs and endanger the vehicle's occupants. Consistent and accurate torque application ensures proper clamping force, preventing these issues.
Q2 What happens if I don't use a torque wrench?
What happens if I don't use a torque wrench?
Using a torque wrench is highly recommended when working on suspension bolts because it allows for accurate and repeatable results. Guessing or simply using hand tools may lead to inconsistent torque values, potentially causing fasteners to loosen over time or damage threads if over-tightened. A torque wrench ensures that each bolt is tightened to the precise manufacturer-specified value, leading to safer and more reliable performance.
Q3 Should I replace suspension bolts when performing maintenance?
Should I replace suspension bolts when performing maintenance?
It is generally recommended to replace certain suspension bolts when performing major suspension work or when a bolt has been removed and reinstalled. Bolts that have been tightened and loosened multiple times may experience slight stretching or deformation, potentially compromising their clamping force and reliability. This is especially true for stretch bolts or torque-to-yield (TTY) bolts, which are designed to yield and must be replaced after use. Consult your service manual to identify if bolts need to be replaced, and follow torque instructions carefully.
Q4 What should I do if I think a bolt has been over-tightened?
What should I do if I think a bolt has been over-tightened?
If you suspect a bolt has been over-tightened, immediately inspect the bolt and surrounding components. Remove the bolt carefully, paying attention to how much resistance it gives. Check if the bolt is visibly damaged. If there is any doubt at all, replace the bolt with a new one and re-torque to the manufacturer’s specification. Over-torqued bolts may stretch, damage threads in the surrounding components, or even crack or break. Don’t reuse potentially compromised fasteners; your safety depends on them.
Q5 How often should I check my suspension components?
How often should I check my suspension components?
A visual inspection of suspension components should be performed periodically, ideally as part of your routine maintenance schedule which may include each oil change, or at least every 6 to 12 months or 10-15,000 miles. Pay attention to any unusual noises, vibrations, or changes in handling. Look for signs of wear, leaks, or damaged components. If you notice issues, consult a qualified mechanic for more thorough inspections. Regular checks can help prevent major repairs and maintain the safety of your vehicle.
Environmental Considerations
Temperature, humidity, and seasonal effects on torque specifications
Temperature Effects
Includes: High Heat, Cold Weather, Thermal Cycling
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
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
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 1/2" drive torque wrench is necessary for applying the correct torque to larger suspension components.
- Wide torque range (e.g., 20-150 ft-lbs)
- Click-type or digital readout
Torque Wrench (3/8" Drive)
A 3/8" drive torque wrench is useful for accessing smaller bolts and applying lower torque specifications.
- Torque range for smaller fasteners (e.g., 5-80 ft-lbs)
- Good for tighter spaces
Socket Set (Metric)
A comprehensive set of metric sockets, including deep sockets, is essential for accessing suspension bolts.
- Variety of sizes from 10mm to 24mm (and potentially larger)
- 6-point and 12-point options
Socket Extensions
Extensions are needed to reach bolts in recessed areas or around other components.
- Various lengths (e.g., 3", 6", 10")
- 3/8" and 1/2" drive
Swivel Joints
Swivel joints (or wobble extensions) help reach bolts at awkward angles.
- 3/8" and 1/2" drive options
- Allows for slight angles in tight spaces
Service Procedures
Front Suspension Lower Control Arm Bolt Torque Procedure
Procedure for torquing the bolts securing the front lower control arms to the subframe and steering knuckle.
- Raise the vehicle and support securely on jack stands.
- Locate the lower control arm mounting bolts.
- Using the appropriate socket, thread bolts until they are snug.
- Torque the lower control arm to subframe bolts to specified torque.
- Torque the lower control arm to steering knuckle bolts to specified torque.
- Ensure all bolts are at the correct torque. Refer to your specific repair manual for the proper torque values for your vehicle trim and suspension type.
- Lower the vehicle.
Rear Suspension Upper Control Arm Bolt Torque Procedure
Procedure for torquing the bolts securing the rear upper control arms to the frame and steering knuckle.
- Raise the vehicle and support securely on jack stands.
- Locate the rear upper control arm mounting bolts.
- Using the appropriate socket, thread bolts until they are snug.
- Torque the upper control arm to frame bolts to specified torque.
- Torque the upper control arm to steering knuckle bolts to specified torque.
- Ensure all bolts are at the correct torque. Refer to your specific repair manual for the proper torque values for your vehicle trim and suspension type.
- Lower the vehicle.
Rear Suspension Lower Control Arm Bolt Torque Procedure
Procedure for torquing the bolts securing the rear lower control arms to the frame and steering knuckle.
- Raise the vehicle and support securely on jack stands.
- Locate the rear lower control arm mounting bolts.
- Using the appropriate socket, thread bolts until they are snug.
- Torque the lower control arm to frame bolts to specified torque.
- Torque the lower control arm to steering knuckle bolts to specified torque.
- Ensure all bolts are at the correct torque. Refer to your specific repair manual for the proper torque values for your vehicle trim and suspension type.
- Lower the vehicle.
Sway Bar Link Bolt Torque Procedure
Procedure for torquing the sway bar link bolts on both front and rear axles.
- Raise the vehicle and support securely on jack stands.
- Locate the sway bar link mounting bolts.
- Using the appropriate socket, thread bolts until they are snug.
- Torque the sway bar link bolts to specified torque at both ends.
- Ensure all bolts are at the correct torque. Refer to your specific repair manual for the proper torque values for your vehicle trim and suspension type.
- Lower the vehicle.
Technical Service Bulletins
Suspension Noise and Creaking
2020-03-15This bulletin addresses reports of creaking or knocking noises emanating from the front suspension. It was discovered that some bolts were under-torqued at the factory.
Resolution: Inspect and re-torque all front suspension bolts to the specified torque as detailed in the service manual. Pay close attention to the lower control arm bolts. Apply thread locker where specified.
Rear Suspension Alignment Issues
2021-08-22This bulletin addresses some issues with rear suspension alignment that can be caused by improperly torqued control arm bolts or by loosening of said bolts over time.
Resolution: Inspect all rear suspension mounting hardware. Torque all control arm fasteners to the correct torque specifications. If wear is noted, components must be replaced prior to performing an alignment. Check rear subframe torque spec and ensure all are torqued.
Steering Knocking Noise
2023-01-10Addresses some steering knock complaints, particularly when turning at low speeds. Issue has been tied to possible loose lower control arm hardware.
Resolution: Inspect lower control arm bolts for proper torque and any signs of wear. Ensure bolts are torqued to the specifications in the repair manual. Replace any worn components and verify proper alignment after repair.
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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.
- Vehicle specifications and procedures may vary by model year, trim level, and region.
- Always follow the manufacturer's recommended procedures and safety precautions.
- Working on vehicles can be dangerous. Always take proper safety precautions and use appropriate safety equipment.
- If you're unsure about any procedure, consult a qualified professional mechanic.