BMW 640i 2011-2018 Suspension Bolt Torque Specifications
This page provides detailed torque specifications for suspension bolts on the 2011-2018 BMW 640i (F12 and F13 generation). It includes front and rear suspension components and is intended for use by automotive professionals and experienced DIYers.
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 Strut Assembly
Torque specifications for components related to the front strut assembly, including mounting points to the chassis and steering knuckle.
1 Upper Strut Mount to Chassis Bolts
M10 x 1.5
Upper Strut Mount to Chassis Bolts
M10 x 1.5Torque Value
Important Notes
2 Lower Strut Mount to Steering Knuckle Bolts
M12 x 1.5
Lower Strut Mount to Steering Knuckle Bolts
M12 x 1.5Important Notes
Front Control Arms
Torque specifications for bolts securing the front control arms to the frame/subframe and steering knuckle.
1 Control Arm to Frame/Subframe Bolts
M14 x 2.0
Control Arm to Frame/Subframe Bolts
M14 x 2.0Torque Value
Important Notes
2 Ball Joint Nut
M12 x 1.5
Ball Joint Nut
M12 x 1.5Torque Value
Important Notes
Steering
Torque specifications for tie rod end nuts and other steering linkage components.
1 Tie Rod End Nut
M12 x 1.25
Tie Rod End Nut
M12 x 1.25Torque Value
Important Notes
Sway Bar
Torque specifications for the sway bar links and mounting brackets.
1 Sway Bar Link Nut
M10 x 1.25
Sway Bar Link Nut
M10 x 1.25Torque Value
Important Notes
2 Sway Bar Mounting Bracket Bolts
M8 x 1.25
Sway Bar Mounting Bracket Bolts
M8 x 1.25Torque Value
Important Notes
Rear Suspension
Torque specifications for rear suspension arms and hub assembly.
1 Rear Lower Control Arm to Subframe Bolts
M14 x 2.0
Rear Lower Control Arm to Subframe Bolts
M14 x 2.0Important Notes
2 Rear Upper Control Arm to Subframe Bolts
M12 x 1.75
Rear Upper Control Arm to Subframe Bolts
M12 x 1.75Important Notes
3 Rear Wheel Hub Assembly Bolts/Nuts
M12 x 1.5
Rear Wheel Hub Assembly Bolts/Nuts
M12 x 1.5Torque Value
Important Notes
Subframes
Torque specifications for bolts securing the front and rear subframes to the vehicle chassis.
1 Front Subframe Bolts
M14 x 2.0
Front Subframe Bolts
M14 x 2.0Important Notes
2 Rear Subframe Bolts
M14 x 2.0
Rear Subframe Bolts
M14 x 2.0Important 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 so important for suspension bolts?
Why are proper torque specifications so important for suspension bolts?
Using the correct torque ensures the fasteners are tight enough to prevent components from loosening during driving, maintaining proper suspension geometry and preventing premature wear. Overtightening can stretch or break bolts and damage threads, while undertightening can lead to movement, noise, and potential failure.
Q2 Can I reuse suspension bolts?
Can I reuse suspension bolts?
While some bolts might appear reusable, many suspension bolts, especially torque-to-yield (TTY) bolts, are designed for single use. Reusing them can compromise their clamping force and increase the risk of failure. Always refer to the BMW repair manual and replace bolts as recommended.
Q3 What are torque-to-yield (TTY) bolts and how are they different?
What are torque-to-yield (TTY) bolts and how are they different?
TTY bolts are designed to stretch upon tightening, providing a more precise and consistent clamping force. They must be replaced after being used. Unlike regular bolts, you generally torque them to a specified value and then turn them a specified angle. Regular bolts can usually be reused, unless signs of damage are present, or otherwise indicated by the manufacturer.
Q4 What tools do I need to properly torque suspension bolts?
What tools do I need to properly torque suspension bolts?
You will need a calibrated torque wrench, sockets of the correct size, and potentially extensions or universal joints for hard-to-reach bolts. For TTY bolts, you might also need an angle gauge to measure the degree of rotation after the initial torque. Always use high-quality tools to ensure accuracy.
Q5 How often should I check my suspension bolt torque?
How often should I check my suspension bolt torque?
It is recommended to check suspension bolt torque periodically, especially after any work has been performed on the suspension or if you notice unusual noises or changes in handling. A good rule of thumb is to check after the first 50-100 miles after suspension work, and then as part of routine service (e.g. during a tire rotation or oil change).
Q6 What happens if I don't torque my bolts to the correct specification?
What happens if I don't torque my bolts to the correct specification?
Under-torquing can result in fasteners loosening, causing clunking noises, poor handling, and potential suspension component failure. Over-torquing can damage threads, stretch or break bolts, and potentially deform suspension components. Both are dangerous and should be avoided.
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 capable of measuring torque values relevant to suspension bolts.
- Accurate torque readings
- Click-type or digital readout
- Range of 20-200 ft-lbs (or equivalent Nm)
Torque Wrench (3/8" Drive)
A 3/8" drive torque wrench for smaller bolts with lower torque specifications.
- Accurate torque readings
- Click-type or digital readout
- Range of 10-100 ft-lbs (or equivalent Nm)
Socket Set (Metric)
A complete set of metric sockets, both standard and deep, for various bolt head sizes.
- Various sizes ranging from 8mm to 24mm
- 6-point sockets preferred
- Chrome vanadium steel for durability
Extension Bars
Extension bars of various lengths to access hard-to-reach bolts.
- 1/2" and 3/8" drive options
- Various lengths
- Durable construction
Wrench Set (Metric)
A set of open end and box wrenches for holding bolts while torquing
- Sizes ranging from 8mm to 24mm
- Combination wrenches preferred
- Chrome vanadium steel
Jack and Jack Stands
A reliable jack and jack stands for safely lifting and supporting the vehicle.
- Adequate weight capacity
- Stable and secure
- Meets or exceeds safety standards
Service Procedures
Front Suspension Strut Bolt Torque Procedure
Procedure for torquing the bolts connecting the front strut assembly to the vehicle.
- Raise and support the vehicle safely.
- Locate the strut mounting bolts.
- Hand-tighten all bolts.
- Torque the upper strut mounting bolts to 75Nm + 90 degrees.
- Torque the lower strut mounting bolts to 100Nm + 90 degrees.
- Verify all bolts are torqued to specification.
- Lower the vehicle and double check tightness
Rear Suspension Control Arm Bolt Torque Procedure
Procedure for torquing the bolts connecting the rear control arms to the vehicle.
- Raise and support the vehicle safely.
- Locate the control arm mounting bolts.
- Hand-tighten all bolts.
- Torque inner control arm bolt to 120 Nm + 90 degrees
- Torque outer control arm bolt to 100 Nm + 90 degrees
- Torque the guide link to chassis bolts to 100Nm + 90 degrees.
- Verify all bolts are torqued to specification.
- Lower the vehicle and double check tightness
Sway Bar End Link Torque Procedure
Procedure for torquing sway bar end link mounting bolts.
- Raise and support the vehicle safely
- Locate the sway bar end link mounting bolts.
- Hand-tighten all bolts.
- Torque end link to strut bolts to 60 Nm
- Torque end link to sway bar bolts to 60 Nm
- Verify all bolts are torqued to specification
- Lower the vehicle and double check tightness
Technical Service Bulletins
Excessive Suspension Noise - Front Struts
2016-05-15Reports of excessive knocking or creaking noises originating from the front suspension, sometimes related to improper torque or damaged components.
Resolution: Inspect strut mounting bolts and torque to specification. Replace any damaged components.
Rear Suspension Alignment Issues
2017-11-20Vehicles experiencing rear suspension alignment issues or premature tire wear may require inspection of rear control arm bolts.
Resolution: Inspect all control arm bolts and torque to specification and perform wheel alignment.
Steering Feedback Issues
2018-01-05Some vehicles exhibit poor steering feedback and vague steering inputs. Check for proper torque of sway bar end links.
Resolution: Inspect and torque sway bar end link bolts. Confirm proper component functionality.
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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.