BMW Z4 2018-present Suspension Bolt Torque Specifications & Fastener Values
BMW Z4 2018-present

BMW Z4 2018-present Suspension Bolt Torque Specifications

This page provides detailed torque specifications for all suspension bolts on the 2018-Present BMW Z4 (G29 generation). Includes front and rear suspension 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 Suspension

This section covers the torque specifications for the front suspension components of the BMW Z4 (2018-Present). These components include the strut assembly, control arms, steering components, and related hardware. Proper torque is crucial for maintaining vehicle handling, alignment, and safety.

1

Strut/Shock Absorber Mounting Bolts

M12 x 1.5
Torque Value
40 ft-lbs (54 N·m)
Important Notes
Secures the strut to the strut tower. Ensure proper alignment before tightening.
2

Control Arm Bolts

M14 x 1.5
Torque Value
70 ft-lbs (95 N·m)
Important Notes
Connects the control arm to the subframe and steering knuckle. Tighten with suspension at ride height if possible.
3

Ball Joint Nut

M12 x 1.25
Torque Value
50 ft-lbs (68 N·m)
Important Notes
Secures the ball joint to the control arm or steering knuckle. Ensure proper seating.
4

Tie Rod End Nut

M10 x 1.25
Torque Value
35 ft-lbs (47 N·m)
Important Notes
Connects the tie rod end to the steering knuckle. Ensure the tie rod end is properly seated.
5

Sway Bar Link Nut

M10 x 1.5
Torque Value
35 ft-lbs (47 N·m)
Important Notes
Connects the sway bar to the strut or control arm. Ensure proper seating of the link.
6

Steering Knuckle to Strut/Shock Bolts

M12 x 1.5
Torque Value
60 ft-lbs (81 N·m)
Important Notes
Connects the strut or shock to the steering knuckle. Check for proper alignment and ensure no binding.

Rear Suspension

This section contains the torque specifications for the rear suspension components of the BMW Z4 (2018-Present). This includes the rear shock absorbers, control arms, and related hardware. Correct torque application is vital for proper handling and safe operation.

1

Rear Shock Absorber Upper Mounting Bolts

M10 x 1.5
Torque Value
40 ft-lbs (54 N·m)
Important Notes
Secures the upper part of the shock absorber to the chassis.
2

Rear Shock Absorber Lower Mounting Bolt

M12 x 1.5
Torque Value
50 ft-lbs (68 N·m)
Important Notes
Connects the lower part of the shock absorber to the suspension arm. Final tightening should be done with the suspension at ride height if possible.
3

Rear Control Arm Bolts

M14 x 1.5
Torque Value
70 ft-lbs (95 N·m)
Important Notes
Connects the rear control arms to the subframe and/or knuckle. Final tightening should be done with the suspension at ride height if possible.

Sway Bar

This section contains the torque specifications for the sway bar and related components. This includes mounting brackets and links that connect the bar to the suspension components. Correct torque application is vital for proper handling and safe operation.

1

Sway Bar Mounting Bracket Bolts

M8 x 1.25
Torque Value
25 ft-lbs (34 N·m)
Important Notes
Secures the sway bar mounting brackets to the vehicle's frame/subframe. Ensure the bracket is properly aligned and there is no binding.

Subframes

This section details the torque specifications for the front and rear subframe mounting bolts. These bolts are critical for vehicle structure and proper suspension operation. These are typically large bolts and require both torque and angle tightening. Note that these values are ESTIMATED based on similar systems and may not be exact.

1

Front Subframe to Chassis Bolts

M16 x 2.0
Important Notes
Secures the front subframe to the vehicle's chassis. Use new bolts as these are typically torque-to-yield type. This value is ESTIMATED.
2

Rear Subframe to Chassis Bolts

M16 x 2.0
Important Notes
Secures the rear subframe to the vehicle's chassis. Use new bolts as these are typically torque-to-yield type. This value is ESTIMATED.

Wheel Hub

This section contains the torque specifications for the wheel hub and bearing assembly. Correct torque application is vital for proper operation and longevity of the bearing. Proper torque also transfers the vehicle's weight correctly into the suspension.

1

Wheel Hub/Bearing Mounting Bolts

M12 x 1.5
Torque Value
60 ft-lbs (81 N·m)
Important Notes
Secures the wheel hub and bearing assembly to the steering knuckle or suspension component. Ensure the hub is correctly positioned and that there is no binding.

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 is it important to use the correct torque specifications for suspension bolts?

Using the correct torque is crucial for safety and performance. Over-tightening can stretch or break bolts, damage components, and affect suspension geometry, leading to premature wear, handling issues, and potential failure. Under-tightening can allow components to shift, resulting in noise, instability, and loss of control. Proper torque ensures the correct clamping force for secure and reliable operation.

Q2

What should I do if I suspect a bolt has been over-torqued?

If you suspect a bolt has been over-torqued, it's best to replace it with a new one. Over-torquing can damage the bolt's threads and structural integrity, making it prone to failure. When replacing, always use the correct torque specifications to avoid repeating the issue. Inspect the surrounding hardware for any sign of damage.

Q3

Do I need to use new bolts when working on the suspension?

While not always mandatory, it's highly recommended to use new bolts, especially self-locking bolts or bolts that have been torqued multiple times, whenever disassembling and reassembling suspension components. These bolts are often designed for a single use, as the locking mechanism can degrade. Using new bolts ensures proper torque and clamping force.

Q4

Can I use an impact wrench for suspension bolts?

While impact wrenches can be useful for initial loosening of bolts, it's not recommended to use them for tightening to the final torque specification. Impact wrenches can easily overtighten bolts, causing damage and potential failure. Use a calibrated torque wrench for accurate and safe fastening, especially for suspension components.

Q5

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

It's recommended to check the torque on your suspension bolts after the initial installation and then periodically, especially after any major suspension work or after driving on rough roads. For regular driving, checking once a year or every 10,000 to 15,000 miles is a good practice. If you notice any unusual noises, vibrations, or handling issues, inspect the torque immediately. For track use, more frequent checks are warranted.

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 accurately tightening suspension bolts to specified torque values. 1/2" drive is recommended for the higher torque values found in suspension components.

  • Click-type mechanism for accurate torque application
  • Wide torque range suitable for suspension components
  • Durable construction for repeated use
Learn more

Torque Wrench (3/8" Drive)

A smaller, 3/8" drive torque wrench is useful for lower torque applications found in certain suspension components or access in tighter areas.

  • Click-type mechanism for accurate torque application
  • Suitable for lower torque ranges
  • Compact design for easy access
Learn more

Socket Set (Metric)

A comprehensive metric socket set, including various sizes to match the suspension bolt heads.

  • Various sizes to accommodate different bolt heads
  • Durable construction for repeated use
  • Clearly marked sizes for easy identification
Learn more

Socket Extensions

Socket extensions of varying lengths will help access recessed or hard to reach suspension bolts.

  • Enables access to recessed bolts
  • Durable for high torque applications
  • Available in various lengths
Learn more

Universal Joint Adapter

A universal joint adapter allows access to bolts at odd angles.

  • Allows access at an angle
  • Durable for high torque applications
  • Provides flexibility in tight spaces
Learn more
Service Procedures

Front Strut Assembly Removal and Installation

This procedure details the removal and reinstallation of the front strut assembly including torque specification for the relevant bolts.

  • Loosen wheel lug bolts.
  • Raise vehicle and secure on jack stands.
  • Remove the wheel.
  • Disconnect any electrical connectors or brake lines attached to the strut assembly.
  • Loosen and remove the pinch bolt at the bottom of the strut and the nut securing the bottom of the strut to the steering knuckle
  • Remove the upper strut mount bolts
  • Remove the strut assembly from the vehicle.
  • Reinstall in reverse order, applying proper torque specifications to all bolts.
  • Torque wheel lug bolts.
  • Lower vehicle.
View full procedure

Rear Suspension Lower Control Arm Replacement

This procedure guides you through replacing the rear lower control arm and includes torque specifics.

  • Loosen wheel lug bolts.
  • Raise the vehicle and secure with jack stands.
  • Remove the wheel.
  • Support the lower control arm with a jack.
  • Loosen and remove the inner and outer bolts from the control arm.
  • Remove the old control arm and install the new control arm.
  • Install new bolts and torque to specifications.
  • Torque wheel lug bolts.
  • Lower the vehicle
View full procedure

Rear Upper Control Arm Replacement

This procedure guides you through replacing the rear upper control arm and includes torque specifics.

  • Loosen wheel lug bolts.
  • Raise the vehicle and secure with jack stands.
  • Remove the wheel.
  • Support the lower control arm with a jack.
  • Loosen and remove the inner and outer bolts from the upper control arm.
  • Remove the old upper control arm and install the new upper control arm.
  • Install new bolts and torque to specifications.
  • Torque wheel lug bolts.
  • Lower the vehicle
View full procedure
Technical Service Bulletins

Suspension Bolt Corrosion

2020-03-15

Some vehicles may experience corrosion on suspension bolts due to exposure to road salts. This can affect proper torque and lead to component failure.

2018-2020

Resolution: Inspect suspension bolts for corrosion. Replace any corroded bolts and apply anti-seize lubricant before torquing. Always adhere to the proper torque specifications to ensure secure installation.

Front Strut Upper Mount Clicking Noise

2021-07-22

Some vehicles may experience clicking noise from the front upper strut mount due to improper torque or bolt stretch.

2018-2021

Resolution: Inspect strut mount bolts for stretch. Remove and replace with new bolts applying the proper torque specification. Also check for wear or damage to the mount itself.

About the Author

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Alan Montanye - Automotive Technical Specialist
ASE

Alan Montanye

Automotive Technical Specialist

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