BMW 840i 2018-present Body & Frame Bolt Torque Specifications
Detailed specifications for body bolt torque settings for the 2018-Present BMW 8 Series, including coupe and gran coupe models.
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
Wheels And Tires
Specifications for components related to the wheels and tires, including lug nuts.
1 Wheel Lug Nuts
M14 x 1.25
Wheel Lug Nuts
M14 x 1.25Torque Value
Important Notes
Fuel System
Specifications for components related to the fuel system, including the fuel tank and filler neck.
1 Fuel Tank Strap Bolts
M8 x 1.25
Fuel Tank Strap Bolts
M8 x 1.25Torque Value
Important Notes
2 Fuel Filler Neck Bolts
M6 x 1.0
Fuel Filler Neck Bolts
M6 x 1.0Torque Value
Important Notes
Electrical System
Specifications for components related to the electrical system, including battery terminals.
1 Battery Terminal Nuts
M6 x 1.0
Battery Terminal Nuts
M6 x 1.0Torque Value
Important Notes
Doors
Specifications for door-related components, including hinges.
1 Door Hinge Bolts (Body Side) - M10
M10 x 1.5
Door Hinge Bolts (Body Side) - M10
M10 x 1.5Torque Value
Important Notes
2 Door Hinge Bolts (Body Side) - M8
M8 x 1.25
Door Hinge Bolts (Body Side) - M8
M8 x 1.25Torque Value
Important Notes
3 Door Hinge Bolts (Body Side) - M6
M6 x 1.0
Door Hinge Bolts (Body Side) - M6
M6 x 1.0Torque Value
Important Notes
Hood
Specifications for hood-related components, including hinges.
1 Hood Hinge Bolts - M8
M8 x 1.25
Hood Hinge Bolts - M8
M8 x 1.25Torque Value
Important Notes
2 Hood Hinge Bolts - M6
M6 x 1.0
Hood Hinge Bolts - M6
M6 x 1.0Torque Value
Important Notes
Exterior Panels
Specifications for exterior body panels such as fenders and bumpers.
1 Fender Bolts - M8
M8 x 1.25
Fender Bolts - M8
M8 x 1.25Torque Value
Important Notes
2 Fender Bolts - M6
M6 x 1.0
Fender Bolts - M6
M6 x 1.0Torque Value
Important Notes
3 Bumper Mounting Bolts - M8
M8 x 1.25
Bumper Mounting Bolts - M8
M8 x 1.25Torque Value
Important Notes
4 Bumper Mounting Bolts - M6
M6 x 1.0
Bumper Mounting Bolts - M6
M6 x 1.0Torque Value
Important Notes
Lighting
Specifications for headlight and tail light mounting.
1 Tail Light/Headlight Mounting Bolts/Nuts
M6 x 1.0
Tail Light/Headlight Mounting Bolts/Nuts
M6 x 1.0Torque Value
Important Notes
Interior
Specifications for interior components such as seats, dashboard, and trim panels.
1 Seat Mounting Bolts
M10 x 1.5
Seat Mounting Bolts
M10 x 1.5Torque Value
Important Notes
2 Dashboard Mounting Bolts/Screws
M6 x 1.0
Dashboard Mounting Bolts/Screws
M6 x 1.0Torque Value
Important Notes
3 Interior Trim Panel Fasteners
Plastic Trim Fastener
Interior Trim Panel Fasteners
Plastic Trim FastenerTorque Value
Important Notes
Roof
Specifications for sunroof components.
1 Sunroof Frame Bolts
M6 x 1.0
Sunroof Frame Bolts
M6 x 1.0Torque Value
Important Notes
Side Panels
Specifications for rocker panels and side skirts.
1 Side Skirt/Rocker Panel Bolts
M6 x 1.0
Side Skirt/Rocker Panel Bolts
M6 x 1.0Torque Value
Important Notes
Rear Panels
Specifications for rear deck and shelf mounting.
1 Rear Deck/Shelf Mounting Bolts/Screws
M6 x 1.0
Rear Deck/Shelf Mounting Bolts/Screws
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 crucial to use the correct torque specifications for body bolts?
Why is it crucial to use the correct torque specifications for body bolts?
Using the correct torque ensures proper clamping force, preventing bolts from loosening due to vibration or thermal expansion. Over-tightening can damage the bolt, the threads in the chassis, or the component being attached, potentially leading to structural failure or squeaks and rattles. Under-tightening may not provide adequate clamping force resulting in loose components, rattles and possible component damage. For example, an improperly torqued fender bolt could allow the fender to shift, causing rubbing and paint damage.
Q2 What tools are needed for tightening body bolts to the correct specifications?
What tools are needed for tightening body bolts to the correct specifications?
A calibrated torque wrench is essential. Depending on the bolt locations, you might also need various sockets, extensions, and possibly a universal joint. For instance, reaching bolts inside the engine bay or under the car often requires socket extensions.
Q3 Can I use a general torque spec if I don't know the specific value?
Can I use a general torque spec if I don't know the specific value?
No. Using a general torque value for body bolts is highly discouraged. Different bolts in different locations will have specific torque specifications based on size, material, and their intended function. Attempting to use a general torque value could result in an over-tightened or under-tightened bolt, which may cause damage to the vehicle. For example, attempting to use the same torque for small trim bolts that's meant for large structural bolts could easily damage the trim, or cause it to break. Always refer to the vehicle-specific repair manual or a reliable database for the correct values.
Q4 How often should I check the torque on body bolts?
How often should I check the torque on body bolts?
For standard service, torque checks are not usually needed unless a component has been removed or worked on. However, after any repair or body work which requires bolt removal or tightening, it is recommended that the bolts be torqued to specification immediately. In some cases, a subsequent torque check may be needed after a settling or 'bedding' in period, typically around 100 to 500 miles of driving. For example, if you've replaced a bumper or a door, re-checking the bolts after some driving is a good practice. For routine maintenance, periodic inspections, such as during an oil change, would be prudent to check for any loose or missing bolts.
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 calibrated torque wrench is essential for accurately tightening body bolts to specification.
- Click-type mechanism for precise torque application
- Range suitable for common body bolt torques (e.g. 10-150 Nm)
Torque Wrench (3/8" Drive)
A smaller torque wrench for access to more restricted areas and lower torque fasteners.
- Click-type mechanism for precise torque application
- Range suitable for smaller body bolt torques (e.g. 5-50 Nm)
Socket Set (Metric)
A comprehensive set of metric sockets in various sizes is needed for different body bolts.
- Includes common sizes (e.g., 8mm, 10mm, 13mm, 16mm, 18mm)
- Made from high-strength materials
Extension Bars
Extension bars assist in reaching bolts that are recessed or located in hard-to-reach areas.
- Various lengths to suit different applications
- Securely connects to sockets and ratchets
Universal Joint
A universal joint allows access to bolts at an angle.
- Provides flexibility for awkward bolt positions
- Durable construction
Service Procedures
Front Bumper Cover Removal and Installation
Procedure for removing and reinstalling the front bumper cover, including torque specifications for all associated fasteners.
- Disconnect any electrical connectors to fog lamps, sensors, etc.
- Remove any fasteners securing the bumper to the fenders and body.
- Carefully detach the bumper cover, paying attention to clips and tabs.
- Install the bumper cover reversing the removal process.
- Tighten all bolts to specified torque values, beginning at the center and moving outward.
Side Skirt Removal and Installation
Procedure for removing and reinstalling the side skirts, including torque specifications for all associated fasteners.
- Locate all fasteners securing the side skirt to the rocker panel and underbody.
- Remove the fasteners carefully, taking note of their position and type.
- Carefully detach the side skirt, paying attention to clips and tabs.
- Install the side skirt, reversing the removal process.
- Tighten all bolts to specified torque values, beginning at the center and moving outward.
Rear Bumper Cover Removal and Installation
Procedure for removing and reinstalling the rear bumper cover, including torque specifications for all associated fasteners.
- Disconnect any electrical connectors to parking sensors, etc.
- Remove any fasteners securing the bumper to the quarter panels and body.
- Carefully detach the bumper cover, paying attention to clips and tabs.
- Install the bumper cover reversing the removal process.
- Tighten all bolts to specified torque values, beginning at the center and moving outward.
Technical Service Bulletins
Possible Body Panel Alignment Issues After Minor Collision
2020-03-15Addresses the issue of body panel alignment issues sometimes being present even with minor impacts. Provides torque specs for proper adjustments.
Resolution: Verify all body panels for proper alignment and torque fasteners to the correct specification. Consult BMW repair manual for torque settings.
Water Intrusion Around Tail Lights and Bumper Seals
2021-11-22Details the causes of water intrusion around tail lights and bumper seal areas, specifying torque procedures when reassembling.
Resolution: Inspect and clean all sealing surfaces, and tighten all fasteners to the specified torque to ensure proper sealing and prevent water leaks. Check for damaged seals and replace as necessary.
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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.