BMW 850i 2018-present Suspension Bolt Torque Specifications
Detailed torque specifications for all suspension bolts on the 2018-Present BMW 8 Series (G15/G16) models, including 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 various components of the front suspension system, including struts, control arms, and related hardware.
1 Strut to Body Mounting Bolts
M10 x 1.5
Strut to Body Mounting Bolts
M10 x 1.5Torque Value
Important Notes
2 Strut to Knuckle Mounting Bolts
M12 x 1.5
Strut to Knuckle Mounting Bolts
M12 x 1.5Torque Value
Important Notes
3 Lower Control Arm to Subframe Bolts
M14 x 1.5
Lower Control Arm to Subframe Bolts
M14 x 1.5Torque Value
Important Notes
4 Lower Control Arm to Knuckle Bolt
M14 x 1.5
Lower Control Arm to Knuckle Bolt
M14 x 1.5Torque Value
Important Notes
5 Ball Joint Nut
M12 x 1.5
Ball Joint Nut
M12 x 1.5Torque Value
Important Notes
6 Upper Control Arm to Frame Bolts
M12 x 1.5
Upper Control Arm to Frame Bolts
M12 x 1.5Torque Value
Important Notes
7 Upper Control Arm to Knuckle Bolts
M12 x 1.5
Upper Control Arm to Knuckle Bolts
M12 x 1.5Torque Value
Important Notes
8 Sway Bar Link Nut
M10 x 1.25
Sway Bar Link Nut
M10 x 1.25Torque Value
Important Notes
Rear Suspension
Torque specifications for rear suspension components, including control arms and trailing arms.
1 Rear Trailing Arm to Chassis Bolts
M14 x 1.5
Rear Trailing Arm to Chassis Bolts
M14 x 1.5Torque Value
Important Notes
2 Rear Trailing Arm to Wheel Carrier Bolts
M14 x 1.5
Rear Trailing Arm to Wheel Carrier Bolts
M14 x 1.5Torque Value
Important Notes
Steering Components
Torque specifications for steering components such as tie rods.
1 Tie Rod End Nut
M12 x 1.25
Tie Rod End Nut
M12 x 1.25Torque Value
Important Notes
Sway Bar Components
Torque specifications for sway bar and related components.
1 Sway Bar Mounting Bracket Bolts
M8 x 1.25
Sway Bar Mounting Bracket Bolts
M8 x 1.25Torque Value
Important Notes
Subframe
Torque specifications for the subframe mounting bolts.
1 Subframe Mounting Bolts
M16 x 2.0
Subframe Mounting Bolts
M16 x 2.0Torque Value
Important Notes
Sensor Components
Torque specifications for wheel speed and ride height sensor mounting hardware.
1 Wheel Speed Sensor Mounting Bolts
M6 x 1.0
Wheel Speed Sensor Mounting Bolts
M6 x 1.0Torque Value
Important Notes
2 Ride Height Sensor Link Bolts
M6 x 1.0
Ride Height Sensor Link Bolts
M6 x 1.0Torque 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 is it important to use the correct torque specifications for suspension bolts?
Why is it important to use the correct torque specifications for suspension bolts?
Using the correct torque ensures the suspension components are securely fastened without being over-tightened or under-tightened. Under-tightening can lead to components loosening over time, causing instability, noise, and potential failure. Over-tightening can damage the bolts, threads, and suspension parts, possibly leading to premature wear or catastrophic failure. Correct torque prevents these issues and preserves the intended performance and safety characteristics of the suspension system.
Q2 What happens if I over-torque a suspension bolt?
What happens if I over-torque a suspension bolt?
Over-torquing a suspension bolt can stretch the bolt beyond its yield point, weakening its integrity. It can also damage the threads in the bolt or the component it's being screwed into. This can lead to premature failure, difficulty removing the bolt later, and even a complete stripping of the threads, requiring costly repairs. In a real-world scenario, an over-torqued control arm bolt could shear under heavy cornering, causing a loss of control.
Q3 What if I don't have a torque wrench?
What if I don't have a torque wrench?
A torque wrench is critical for accurately tightening suspension bolts. Relying on guesswork or feel can easily lead to over- or under-tightening, as outlined above. While 'good and tight' might seem reasonable, suspension components require precise torque values for safety and performance. Using an inexpensive torque wrench over risking a dangerous failure is strongly recommended. It is not advisable to perform suspension repairs without access to a torque wrench
Q4 Are torque specifications different for aluminum vs. steel suspension components?
Are torque specifications different for aluminum vs. steel suspension components?
Yes, torque specifications can vary depending on the material of the components and bolts. Aluminum components generally require lower torque settings than steel to prevent deformation or thread stripping. For BMW vehicles, specific torque settings are provided for each bolt material, and these should always be followed. Always refer to the official repair documentation for your specific vehicle and model
Q5 Should I reuse suspension bolts?
Should I reuse suspension bolts?
BMW often recommends replacing certain suspension bolts, especially those that are torque-to-yield (TTY). TTY bolts are designed to stretch during tightening and are not meant to be reused as their clamping force is compromised. Reusing them can result in improper fastening and potential failure. Always check the BMW repair manual for specific bolt replacement recommendations before reassembly, as it is crucial for safety and reliability.
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 essential for achieving accurate torque specifications on suspension components.
- Wide torque range (typically 20-250 ft-lbs)
- Audible click indicating desired torque reached
- Easy to read scale
Torque Wrench (3/8" Drive)
A 3/8" drive torque wrench is useful for lower torque applications and smaller bolts.
- Torque range (typically 5-80 ft-lbs)
- Provides more precise measurements for smaller components
- Compact design
Socket Set (Metric)
A complete set of metric sockets is necessary to fit various bolt heads on the BMW 850i's suspension.
- Includes commonly used sizes for suspension components
- Both shallow and deep sockets
- Durable construction
Wrench Set (Metric)
A set of metric wrenches may be required for holding nuts in place while tightening bolts.
- Open end and box end wrenches
- Various sizes to fit most suspension hardware
- Durable steel construction
Breaker Bar
A breaker bar provides additional leverage for breaking loose stubborn bolts, particularly on suspension components.
- Long handle for increased leverage
- Durable construction to withstand high torque
- Typically used with sockets
Jack Stands
Essential for safely supporting the vehicle after lifting for suspension work.
- Adjustable height to accommodate different vehicles
- Sturdy base for stability
- Rated load capacity for safety
Vehicle Jack
Required for lifting the vehicle to access the suspension components.
- Hydraulic or scissor type jack
- Rated lifting capacity for safety
- Stable lifting point
Service Procedures
Front Suspension Lower Control Arm Bolt Replacement
Procedure for replacing the lower control arm bolts on the front suspension of a 2018+ BMW 850i.
- Loosen wheel lug bolts, raise vehicle with jack and support with jack stands.
- Remove wheel.
- Locate the lower control arm bolts.
- Using the appropriate sized socket and breaker bar, break loose the lower control arm bolts.
- Using the torque wrench, tighten the bolts to the specified torque, noting the required angle tightening if specified.
- Reinstall the wheel, lower the vehicle, and torque wheel lug bolts to specifications.
Rear Suspension Upper Control Arm Bolt Replacement
Procedure for replacing the upper control arm bolts on the rear suspension of a 2018+ BMW 850i.
- Loosen wheel lug bolts, raise vehicle with jack and support with jack stands.
- Remove wheel.
- Locate the upper control arm bolts.
- Using the appropriate sized socket and breaker bar, break loose the upper control arm bolts.
- Using the torque wrench, tighten the bolts to the specified torque, noting the required angle tightening if specified.
- Reinstall the wheel, lower the vehicle, and torque wheel lug bolts to specifications.
Strut to Wheel Carrier Bolt Replacement
Procedure for replacing the strut to wheel carrier bolts.
- Loosen wheel lug bolts, raise vehicle with jack and support with jack stands.
- Remove wheel.
- Locate the strut to wheel carrier bolts.
- Using the appropriate sized socket and breaker bar, break loose the bolts connecting the strut to the wheel carrier.
- Using the torque wrench, tighten the bolts to the specified torque, noting the required angle tightening if specified.
- Reinstall the wheel, lower the vehicle, and torque wheel lug bolts to specifications.
Technical Service Bulletins
Suspension Bolt Corrosion Issues
2020-05-15Some 2018-2020 BMW 8 series models may experience accelerated corrosion on suspension fasteners, especially in areas with high road salt exposure.
Resolution: Inspect all suspension bolts for corrosion. If any are found, replace with new fasteners and apply a corrosion inhibitor. Ensure correct torque specifications are followed during reassembly.
Rear Suspension Alignment Bolt Torque
2021-11-01A revision was made to the rear alignment bolt torque specifications on the 2018-2021 models, due to complaints of premature bushing wear.
Resolution: Consult the updated torque specifications in the official BMW service manual for proper torque application. These specs can be found through your dealership or online.
Front Suspension Creaking Noise
2022-08-20Reports of creaking noises originating from the front suspension have been attributed to improperly torqued stabilizer bar link bolts.
Resolution: Inspect the front stabilizer bar link bolts. Remove and re-install using the correct torque and angle specifications. Apply a small amount of thread locker to prevent future loosening. Make sure the vehicle is on the ground while torqueing.
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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.