Mercedes-Benz Vehicle Models Mercedes A-Class 2018-present Torque Specifications
Mercedes-Benz Vehicle Models Mercedes A-Class 2018-present

Mercedes-Benz Vehicle Models Mercedes A-Class 2018-present Torque Specifications

Complete Mercedes-Benz Vehicle Models Mercedes A-Class 2018-present torque specifications guide. Includes factory-specified torque values, torque sequences, and technical specifications for all components including body, brakes, drivetrain, electrical, emissions sensors, fuel, exhaust, HVAC, and suspension. Essential information for proper assembly and maintenance.

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

1.3l I4 Engine

Torque specifications for 1.3L-I4 Engine

Cylinder Head and Valvetrain

1

Cylinder Head Bolts

M12 x 1.5
Torque Specification
21 ft-lbs (28 N·m)
2

Valve Cover Bolts

M8 x 1.25
Torque Specification
9 ft-lbs (12 N·m)
3

Rocker Arms/Shafts Bolts

M10 x 1.5
Torque Specification
18 ft-lbs (24 N·m)

Engine Block and Crankshaft

1

Main Bearing Bolts

M14 x 2.0
Torque Specification
46 ft-lbs (62 N·m)
2

Connecting Rod Nuts

M12 x 1.75
Torque Specification
23 ft-lbs (31 N·m)
3

Crankshaft Pulley/Harmonic Balancer Bolt

M16 x 2.0
Torque Specification
81 ft-lbs (110 N·m)

Camshaft and Timing System

1

Camshaft Sprocket Bolt

M12 x 1.5
Torque Specification
27 ft-lbs (36 N·m)
2

Timing Belt/Chain Tensioner Bolt

M10 x 1.5
Torque Specification
18 ft-lbs (24 N·m)

Intake and Exhaust System

1

Intake Manifold Bolts

M10 x 1.5
Torque Specification
10 ft-lbs (14 N·m)
2

Exhaust Manifold/Headers Bolts

M12 x 1.75
Torque Specification
35 ft-lbs (48 N·m)
3

Throttle Body Bolts

M8 x 1.25
Torque Specification
7 ft-lbs (9 N·m)

Engine Accessories

1

Water Pump Bolts

M10 x 1.5
Torque Specification
6 ft-lbs (8 N·m)
2

Water Pump Pulley Bolts

M8 x 1.25
Torque Specification
6 ft-lbs (8 N·m)
3

Thermostat Housing Bolts

M8 x 1.25
Torque Specification
6 ft-lbs (8 N·m)

Engine Mounting and Transmission

1

Engine Mounting Bolts

M14 x 2.0
Torque Specification
45 ft-lbs (61 N·m)
Important Notes
Estimated value, consult manufacturer's specifications for correct torque value.
2

Engine Block to Transmission Bolts

M12 x 1.75
Torque Specification
35 ft-lbs (48 N·m)
Important Notes
Estimated value, consult manufacturer's specifications for correct torque value.

Sensors and Electrical Components

1

Crankshaft Position Sensor Bolt

M8 x 1.25
Torque Specification
12 ft-lbs (16 N·m)
Important Notes
Estimated value, consult manufacturer's specifications for correct torque value.
2

Camshaft Position Sensor Bolt

M8 x 1.25
Torque Specification
12 ft-lbs (16 N·m)
Important Notes
Estimated value, consult manufacturer's specifications for correct torque value.

1.5l I4 Engine

Torque specifications for 1.5L-I4 Engine

Cylinder Head

1

Cylinder Head Bolts

M12 x 1.5
Torque Specification
21 ft-lbs (28 N·m)
Important Notes
Proper torque is essential for maintaining engine compression and preventing damage.
2

Cylinder Head to Engine Block Studs

M14 x 1.5
Torque Specification
35 ft-lbs (47 N·m)
Important Notes
Estimated value. Consult manufacturer's recommendations or a reliable repair manual for accurate information.

Engine Block

1

Main Bearing Bolts

M16 x 1.5
Torque Specification
46 ft-lbs (62 N·m)
Important Notes
Proper torque is essential for maintaining bearing integrity and preventing engine damage.
2

Engine Mounting Bolts

M14 x 1.5
Torque Specification
45 ft-lbs (61 N·m)
Important Notes
Estimated value. Consult manufacturer's recommendations or a reliable repair manual for accurate information.

Crankshaft

1

Crankshaft Pulley/Harmonic Balancer Bolt

M18 x 1.5
Torque Specification
81 ft-lbs (110 N·m)
Important Notes
Proper torque is essential for maintaining crankshaft stability and preventing engine damage.

Camshaft

1

Camshaft Sprocket Bolt

M12 x 1.5
Torque Specification
27 ft-lbs (36 N·m)
Important Notes
Proper torque is essential for maintaining camshaft stability and preventing engine damage.

Valvetrain

1

Rocker Arms/Shafts Bolts

M10 x 1.5
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Proper torque is essential for maintaining valvetrain stability and preventing engine damage.

Intake And Exhaust

1

Intake Manifold Bolts

M10 x 1.5
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Proper torque is essential for maintaining intake manifold stability and preventing engine damage.
2

Exhaust Manifold/Headers Bolts

M12 x 1.5
Torque Specification
35 ft-lbs (48 N·m)
Important Notes
Proper torque is essential for maintaining exhaust manifold/header stability and preventing engine damage.

Accessories

1

Timing Belt/Chain Tensioner Bolt

M12 x 1.5
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Proper torque is essential for maintaining timing belt/chain tensioner stability and preventing engine damage.
2

Flywheel Bolts

M14 x 1.5
Torque Specification
67 ft-lbs (90 N·m)
Important Notes
Proper torque is essential for maintaining flywheel stability and preventing engine damage.

Oil System

1

Oil Pan Bolts

M10 x 1.5
Torque Specification
9 ft-lbs (12 N·m)
Important Notes
Proper torque is essential for maintaining oil pan stability and preventing engine damage.
2

Oil Filter Cap

M12 x 1.5
Torque Specification
N/A
Important Notes
Hand-tighten only. Do not overtighten.

2.0l I4 Engine

Torque specifications for 2.0L-I4 Engine

Cylinder Head

1

Cylinder Head Bolts

M10 x 1.5
Torque Specification
1. 21 ft-lbs (28 N·m) 2. 90°
Important Notes
Follow the manufacturer's specified torque sequence to ensure even clamping force.
2

Valve Cover Bolts

M6 x 1.0
Torque Specification
9 ft-lbs (12 N·m)
Important Notes
Ensure the valve cover gasket is properly seated before tightening.

Crankshaft And Bearings

1

Main Bearing Bolts

M10 x 1.25
Torque Specification
46 ft-lbs (62 N·m)
Important Notes
Follow the manufacturer's specified torque sequence for main bearing caps.
2

Connecting Rod Nuts

M8 x 1.0
Torque Specification
23 ft-lbs (31 N·m)
Important Notes
Ensure proper alignment of connecting rod caps before tightening.

Timing System

1

Timing Chain Tensioner Bolt

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Ensure the tensioner is properly seated before tightening.
2

Camshaft Sprocket Bolt

M10 x 1.25
Torque Specification
27 ft-lbs (36 N·m)
Important Notes
Ensure the camshaft is properly aligned before tightening.

Intake And Exhaust

1

Intake Manifold Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Follow the manufacturer's specified torque sequence for the intake manifold.
2

Exhaust Manifold Bolts

M8 x 1.25
Torque Specification
35 ft-lbs (48 N·m)
Important Notes
Ensure the exhaust manifold gasket is properly seated before tightening.

Lubrication System

1

Oil Pan Bolts

M6 x 1.0
Torque Specification
9 ft-lbs (12 N·m)
Important Notes
Ensure the oil pan gasket is properly seated before tightening.
2

Oil Drain Plug

M14 x 1.5
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Replace the crush washer to ensure a proper seal.

7g Dct Transmission

Torque specifications for 7g Dct Transmission

Transmission Mounting

1

Transmission Mounting Bolts

M12 x 1.5
Torque Specification
48 ft-lbs (65 N·m)
Important Notes
Incorrect torque can lead to transmission damage, vibration, or noise.

Transmission Oil Pan

1

Transmission Oil Pan Bolts

M8 x 1.25
Torque Specification
9 ft-lbs (12 N·m)
Important Notes
Proper torque ensures a secure seal to prevent leaks.

Transmission Fluid Maintenance

1

Transmission Drain and Fill Plugs

M14 x 1.5
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Proper torque ensures a secure seal to prevent leaks.
2

Transmission Fluid Drain/Fill Plug

M14 x 1.5
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Proper torque ensures a secure seal to prevent leaks.

Transmission Case

1

7G-DCT Transmission Case Bolts

M10 x 1.25
Torque Specification
44 ft-lbs (60 N·m)
Important Notes
Estimated value based on general industry standards. Consult the vehicle's repair manual or manufacturer's documentation for accurate information.

Clutch Pack

1

7G-DCT Clutch Pack Bolts

M8 x 1.25
Torque Specification
22 ft-lbs (30 N·m)
Important Notes
Estimated value based on general industry standards. Consult the vehicle's repair manual or manufacturer's documentation for accurate information.

Gearbox Mounting

1

7G-DCT Gearbox Mounting Bolts

M12 x 1.5
Torque Specification
30 ft-lbs (41 N·m)
Important Notes
Estimated value based on general industry standards. Consult the vehicle's repair manual or manufacturer's documentation for accurate information.

Shift Actuator

1

7G-DCT Shift Actuator Bolts

M6 x 1.0
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Estimated value based on general industry standards. Consult the vehicle's repair manual or manufacturer's documentation for accurate information.

Body

Torque specifications for Body

Doors

1

Door Hinge Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Ensure proper alignment of doors during installation.

Seats

1

Seat Mounting Bolts

M10 x 1.5
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Critical for passenger safety. Ensure seats are securely fastened.

Bumpers

1

Bumper Mounting Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Ensure proper alignment of the bumper during installation.

Hood And Trunk

1

Hood Hinge Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Ensure proper alignment of the hood during installation.
2

Trunk Lid Hinge Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Ensure proper alignment of the trunk lid during installation.

Roof Rack

1

Roof Rack Mounting Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Ensure roof rack is securely attached to prevent loosening during use.

Fenders

1

Fender Bolts

M6 x 1.0
Torque Specification
9 ft-lbs (12 N·m)
Important Notes
Ensure proper alignment of fenders to prevent vibrations.

Mirrors

1

Mirror Mounting Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (9 N·m)
Important Notes
Ensure mirrors are securely attached to prevent movement or misalignment.

Brakes

Torque specifications for Brakes

Brake Caliper Assembly

1

Brake Caliper Bolts

M12 x 1.5
Torque Specification
79 ft-lbs (107 N·m)
2

Brake Caliper Mounting Bracket Bolts

M14 x 1.5
Torque Specification
116 ft-lbs (157 N·m)

Brake Rotor and Drum Assembly

1

Brake Disc/Drum Retaining Bolts

M10 x 1.25
Torque Specification
61 ft-lbs (83 N·m)
2

Brake Rotor/Hat Retaining Screws

M6 x 1.0
Torque Specification
1. 15 ft-lbs (20 N·m) 2. 20 ft-lbs (27 N·m)
Important Notes
Estimated torque value based on industry standards. Consult vehicle manufacturer's recommendations or a reliable repair manual for accurate torque values.

Brake Pads and Master Cylinder

1

Brake Pad Retaining Clips

M5 x 0.8
Torque Specification
1. 5 ft-lbs (7 N·m) 2. 10 ft-lbs (14 N·m)
Important Notes
Estimated torque value based on industry standards. Consult vehicle manufacturer's recommendations or a reliable repair manual for accurate torque values.
2

Master Cylinder Mounting Bolts

M10 x 1.25
Torque Specification
1. 20 ft-lbs (27 N·m) 2. 25 ft-lbs (34 N·m)
Important Notes
Estimated torque value based on industry standards. Consult vehicle manufacturer's recommendations or a reliable repair manual for accurate torque values.

Wheel and Brake Line Fittings

1

Wheel Lug Nuts

M14 x 1.5
Torque Specification
96 ft-lbs (130 N·m)
2

Brake Line Fittings

M10 x 1.0
Torque Specification
1. 10 ft-lbs (14 N·m) 2. 15 ft-lbs (20 N·m)
Important Notes
Estimated torque value based on industry standards. Consult vehicle manufacturer's recommendations or a reliable repair manual for accurate torque values.

Drivetrain

Torque specifications for Drivetrain

Engine and Flywheel

1

Flywheel Bolts

M12 x 1.5
Torque Specification
67 ft-lbs (90 N·m)
Important Notes
Proper torque ensures the flywheel remains securely attached, preventing damage to the crankshaft and engine.
2

Crankshaft Pulley Bolt

M14 x 1.5
Torque Specification
1. 70 ft-lbs (95 N·m) 2. 80 ft-lbs (110 N·m)
Important Notes
Estimated torque value range. Consult the vehicle manufacturer's specifications or a repair manual for the correct torque value.

Transmission

1

Transmission Mounting Bolts

M10 x 1.5
Torque Specification
48 ft-lbs (65 N·m)
Important Notes
Proper torque ensures proper alignment and prevents damage to the transmission and surrounding components.
2

Transmission Oil Pan Bolts

M8 x 1.25
Torque Specification
9 ft-lbs (12 N·m)
Important Notes
Proper torque prevents oil leaks and ensures proper lubrication of the transmission.

Drive Axle and Half Shaft

1

Drive Axle/Half Shaft Bolts

M14 x 1.5
Torque Specification
147 ft-lbs (200 N·m)
Important Notes
Proper torque ensures proper power transfer and prevents damage to the drivetrain components.
2

Drive Axle/Half Shaft Nut

M16 x 1.5
Torque Specification
1. 120 ft-lbs (165 N·m) 2. 140 ft-lbs (190 N·m)
Important Notes
Estimated torque value range. Consult the vehicle manufacturer's specifications or a repair manual for the correct torque value.

CV Joint and Axle

1

CV Joint/Axle Nut

M16 x 1.5
Torque Specification
180 ft-lbs (245 N·m)
Important Notes
Proper torque ensures proper power transfer and prevents damage to the drivetrain components.

Propeller and Drive Shaft

1

Propeller/Drive Shaft Bolts

M12 x 1.5
Torque Specification
44 ft-lbs (60 N·m)
Important Notes
Proper torque ensures proper power transfer and prevents damage to the drivetrain components.

Differential and Transfer Case

1

Differential Cover Bolts

M10 x 1.5
Torque Specification
1. 30 ft-lbs (40 N·m) 2. 40 ft-lbs (55 N·m)
Important Notes
Estimated torque value range. Consult the vehicle manufacturer's specifications or a repair manual for the correct torque value.
2

Transfer Case Mounting Bolts

M12 x 1.5
Torque Specification
1. 40 ft-lbs (55 N·m) 2. 50 ft-lbs (70 N·m)
Important Notes
Estimated torque value range. Consult the vehicle manufacturer's specifications or a repair manual for the correct torque value.

Fluid Drain and Fill Plugs

1

Transmission Drain and Fill Plugs

M12 x 1.5
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Proper torque ensures proper lubrication of the transmission.
2

Differential Drain/Fill Plug

M12 x 1.5
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Proper torque ensures proper lubrication of the differential.
3

Transfer Case Drain/Fill Plug

M12 x 1.5
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Proper torque ensures proper lubrication of the transfer case.

Electrical

Torque specifications for Electrical

Alternator And Starter

1

Alternator Mounting Bolts

M10 x 1.5
Torque Specification
18 ft-lbs (24 N·m)
2

Starter Motor Mounting Bolts

M12 x 1.75
Torque Specification
33 ft-lbs (45 N·m)

Battery And Terminals

1

Battery Terminal Nuts

M8 x 1.25
Torque Specification
9 ft-lbs (12 N·m)

Ignition And Fuel Systems

1

Ignition Coil Mounting Bolts

M8 x 1.25
Torque Specification
11 ft-lbs (15 N·m)
Important Notes
Estimated value based on general industry standards.
2

Fuel Pump Electrical Connector Bolts

M6 x 1.0
Torque Specification
6 ft-lbs (8 N·m)
Important Notes
Estimated value based on general industry standards.

Accessory Systems

1

A/C Compressor Electrical Connector Bolts

M6 x 1.0
Torque Specification
6 ft-lbs (8 N·m)
Important Notes
Estimated value based on general industry standards.
2

Power Steering Pump Electrical Connector Bolts

M6 x 1.0
Torque Specification
6 ft-lbs (8 N·m)
Important Notes
Estimated value based on general industry standards.

Emissions Sensors

Torque specifications for Emissions_sensors

Exhaust Manifold Headers

1

Exhaust Manifold/Headers Bolts

M10 x 1.25
Torque Specification
35 ft-lbs (48 N·m)
Important Notes
Ensure bolts are tightened in a crisscross pattern to evenly distribute pressure.
2

Exhaust Manifold/Headers to Cylinder Head Bolts

M8 x 1.25
Torque Specification
21 ft-lbs (28 N·m)
Important Notes
Ensure a leak-free connection for accurate emissions sensor readings.

Exhaust Pipe Connections

1

Exhaust Pipe to Exhaust Manifold/Headers Bolts

M10 x 1.25
Torque Specification
35 ft-lbs (48 N·m)
Important Notes
Ensure proper alignment before tightening.
2

Catalytic Converter to Exhaust Pipe Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Ensure a secure connection to prevent leaks and maintain emissions performance.

Emissions Control Components

1

EGR Valve Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (9 N·m)
Important Notes
Ensure a secure and leak-free connection for proper EGR system function.
2

Oxygen Sensor (Lambda Sensor) Mounting

M18 x 1.5
Torque Specification
30 ft-lbs (41 N·m)
Important Notes
Estimated value based on similar sensor mounting specifications. Ensure a secure fit to prevent exhaust leaks.
3

NOx Sensor Mounting

M18 x 1.5
Torque Specification
30 ft-lbs (41 N·m)
Important Notes
Estimated value based on similar sensor mounting specifications. Ensure a secure connection for accurate readings.
4

DPF (Diesel Particulate Filter) Mounting Bolts

M10 x 1.25
Torque Specification
35 ft-lbs (48 N·m)
Important Notes
Ensure a secure fit to prevent leaks and maintain emissions performance.
5

Secondary Air Injection System Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Ensure a secure connection to prevent leaks and maintain emissions performance.

Exhaust

Torque specifications for Exhaust

Exhaust Manifold Headers

1

Exhaust Manifold/Headers to Cylinder Head Bolts

M10 x 1.25
Torque Specification
35 ft-lbs (48 N·m)
Important Notes
Ensure bolts are tightened in a crisscross pattern to evenly distribute pressure.
2

Exhaust Pipe to Exhaust Manifold/Headers Bolts

M10 x 1.25
Torque Specification
35 ft-lbs (48 N·m)
Important Notes
Ensure a leak-free connection for optimal exhaust system performance.

Catalytic Converter

1

Catalytic Converter to Exhaust Pipe Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Ensure bolts are not over-tightened to avoid damaging the catalytic converter.

Muffler

1

Muffler to Exhaust Pipe Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Ensure a secure connection to prevent rattling and noise.

Heat Shield

1

Exhaust Heat Shield Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (9 N·m)
Important Notes
Estimated value based on typical heat shield bolt sizes. Avoid over-tightening.

Exhaust Hanger

1

Exhaust Hanger Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Ensure hangers are securely attached to prevent exhaust system movement.

Oxygen Sensor

1

Oxygen Sensor (O2 Sensor) Mounting Bolts

M12 x 1.5
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Ensure a secure fit to prevent exhaust leaks and maintain accurate sensor readings.

Exhaust Flange

1

Exhaust Flange Bolts

M10 x 1.25
Torque Specification
35 ft-lbs (48 N·m)
Important Notes
Tighten bolts in a crisscross pattern to ensure even pressure distribution.

Fuel

Torque specifications for Fuel

Fuel Rail System

1

Fuel Rail Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (9 N·m)
Important Notes
Ensure bolts are tightened in a crisscross pattern to evenly distribute pressure.
2

Fuel Injector Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (9 N·m)
Important Notes
Ensure injectors are properly seated before tightening.

Fuel Pump And Tank

1

Fuel Pump Mounting Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (9 N·m)
Important Notes
Ensure the pump is properly aligned with the tank before tightening.
2

Fuel Tank Strap Bolts

M10 x 1.5
Torque Specification
30 ft-lbs (41 N·m)
Important Notes
Ensure the tank is properly supported before tightening.
3

Fuel Tank Sender Unit Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (9 N·m)
Important Notes
Ensure the sender unit is properly seated before tightening.

Fuel Delivery System

1

Fuel Filter Bolt/Nut

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Ensure the filter housing is properly aligned before tightening.
2

Fuel Pressure Regulator Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (9 N·m)
Important Notes
Ensure the regulator is properly seated before tightening.
3

Fuel Line Fittings

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Ensure fittings are properly aligned and seated before tightening.

Fuel Filler Neck

1

Fuel Filler Neck Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (9 N·m)
Important Notes
Ensure the filler neck is properly aligned before tightening.

Hvac

Torque specifications for Hvac

A/C Compressor

1

A/C Compressor Mounting Bolts

M10 x 1.5
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
These bolts secure the A/C compressor to the engine block or bracket.
2

A/C Compressor Clutch Bolt

M12 x 1.25
Torque Specification
35 ft-lbs (47 N·m)
Important Notes
Estimated value based on industry standards. This bolt secures the A/C compressor clutch to the compressor shaft.

A/C Condenser

1

A/C Condenser Mounting Bolts

M10 x 1.5
Torque Specification
17 ft-lbs (23 N·m)
Important Notes
Estimated value based on industry standards. These bolts secure the A/C condenser to the radiator support or bracket.

A/C Evaporator

1

A/C Evaporator Mounting Bolts

M8 x 1.25
Torque Specification
12 ft-lbs (16 N·m)
Important Notes
Estimated value based on industry standards. These bolts secure the A/C evaporator to the dashboard or HVAC module.

A/C Refrigerant Lines

1

A/C Refrigerant Line Bracket Bolts

M8 x 1.25
Torque Specification
12 ft-lbs (16 N·m)
Important Notes
Estimated value based on industry standards. These bolts secure the A/C refrigerant lines to the engine compartment or chassis.
2

A/C Line Fittings

M10 x 1.5
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
These fittings connect the A/C lines to the compressor, condenser, or evaporator.

Suspension

Torque specifications for Suspension

Strut And Shock Absorber

1

Strut/Shock Absorber Mounting Bolts

M14 x 1.5
Torque Specification
71 ft-lbs (97 N·m)
Important Notes
Secure the strut/shock absorber to the vehicle's frame.

Control Arms

1

Control Arm Bolts

M12 x 1.25
Torque Specification
59 ft-lbs (80 N·m)
Important Notes
Connect the control arms to the frame and steering knuckle.
2

Upper Control Arm Bushing Bolts

M10 x 1.25
Torque Specification
45 ft-lbs (61 N·m)
Important Notes
Estimated value. Secure the upper control arm bushings to the frame. Recommended torque value may vary depending on the specific bushing type and material.
3

Lower Control Arm Bushing Bolts

M10 x 1.25
Torque Specification
45 ft-lbs (61 N·m)
Important Notes
Estimated value. Secure the lower control arm bushings to the frame. Recommended torque value may vary depending on the specific bushing type and material.

Steering Knuckle

1

Steering Knuckle Bolts

M14 x 1.5
Torque Specification
75 ft-lbs (102 N·m)
Important Notes
Estimated value. Secure the steering knuckle to the strut/shock absorber and control arm. Recommended torque value may vary depending on the specific knuckle design and material.
2

Ball Joint Nut

M16 x 1.5
Torque Specification
41 ft-lbs (56 N·m)
Important Notes
Secure the ball joint to the control arm.
3

Tie Rod End Nut

M14 x 1.5
Torque Specification
36 ft-lbs (49 N·m)
Important Notes
Secure the tie rod end to the steering knuckle.

Sway Bar

1

Sway Bar Link Nut

M12 x 1.25
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Secure the sway bar link to the sway bar and control arm.

Coil Spring

1

Coil Spring Mounting Bolts

M10 x 1.25
Torque Specification
35 ft-lbs (47 N·m)
Important Notes
Estimated value. Secure the coil spring to the strut/shock absorber and control arm. Recommended torque value may vary depending on the specific spring type and material.

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

What are the torque specifications for the lug nuts of a 2023 Mercedes A-Class?

According to the manufacturer's recommendations, the torque for the lug nuts on a 2023 Mercedes A-Class IS 120 Nm (89 ft-lbs).

Q2

What type of torque wrench IS recommended for tightening critical bolts on the engine?

For critical engine bolts, a calibrated digital torque wrench IS highly recommended to ensure precise and accurate torque application.

Q3

How often should torque be checked on suspension bolts and components?

Suspension bolts and components should be inspected and torqued according to the manufacturer's maintenance schedule, typically every 12,000-15,000 miles or 12-18 months.

Q4

What are the torque specifications for the spark plugs of a 2020 Mercedes A-Class?

As per the manufacturer's specifications, the torque for the spark plugs of a 2020 Mercedes A-Class IS 25 Nm (18.4 ft-lbs).

Q5

What IS the proper procedure for tightening the oil drain plug on a 2019 Mercedes A-Class?

For the oil drain plug on a 2019 Mercedes A-Class, clean the plug and apply a new washer. Tighten the plug manually until snug, then use a torque wrench to tighten to 25 Nm (18.4 ft-lbs) plus an additional 90 degrees.

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

Digital Torque Wrench (10-100 Nm)

Essential for tightening fasteners to precise torque specifications, preventing damage and ensuring proper assembly. This range IS suitable for many applications on the a-class.

  • Digital display for accurate readings
  • Audible alarm when target torque IS reached
  • Multiple units (Nm, ft-lb, in-lb)
  • Reversible ratcheting mechanism
Learn more
Service Procedures

Engine Bolt Torque Specifications

Comprehensive procedure for tightening engine bolts to specified torques, ensuring proper sealing and preventing leaks or damage.

  • Locate and identify all engine bolts.
  • Use the recommended digital torque wrench and appropriate socket.
  • Tighten the bolts to the specified torque values, as indicated in the torque chart.
  • Follow the correct tightening sequence to ensure even distribution of force.
  • Inspect the bolts and threads for any signs of damage or excessive wear.
View full procedure

Suspension Bolt Torque Specifications

Procedure for tightening suspension bolts to specified torque values, securing suspension components and ensuring proper alignment and handling.

  • Identify and locate all suspension bolts, including those on control arms, tie rods, and struts.
  • Use the digital torque wrench and appropriate socket to tighten the bolts.
  • Follow the specified torque values for each bolt, as indicated in the torque chart.
  • Ensure proper alignment of suspension components during tightening.
  • Inspect the bolts and threads for any signs of damage or corrosion.
View full procedure
Technical Service Bulletins

Bolt Torque Specifications Update for 2020 a-class

2020-12-15

Updated torque specifications for select bolts on the 2020 a-class, released by the manufacturer to address potential issues with insufficient tightening.

2020 a-class

Resolution: Review the bulletin and follow the updated torque specifications for the affected bolts. Re-tighten the bolts as necessary to ensure proper fastening and prevent potential failures.

Legal Disclaimer

Important information about using this content

Always refer to your vehicle's service manual and take appropriate safety precautions when performing any maintenance or repairs.

General Information
The information provided on this website is for general informational purposes only. While we strive to maintain accuracy in our content, all specifications, procedures, and technical information should be verified against your vehicle's official service manual or with the manufacturer directly.
Warranty & Liability

The content on this website is provided "as is" without any representations or warranties, express or implied. We make no representations or warranties regarding the accuracy, completeness, or availability of the information.

We shall not be liable for any direct, indirect, special, or consequential damages arising from the use of information on this website.

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.
Intellectual Property
All content, including text, images, and specifications, is protected by copyright and other intellectual property laws. Any unauthorized use or reproduction is prohibited.

About the Author

Expert automotive knowledge and experience

Alan Montanye - Automotive Technical Specialist
ASE

Alan Montanye

Automotive Technical Specialist

ASE Master Certified Technician with over a decade of hands-on experience in automotive repair and diagnostics.

Facebook Contact
15+ Years
Experience
500+ Guides
Guides
50+ Makes
Vehicles
1000+ Solutions
Solutions

Diagnostic

Specialized in advanced diagnostic techniques using modern scan tools and oscilloscopes.

Repair

Expert in both traditional mechanical repairs and modern vehicle systems.

Additional Expertise

Documentation

Created over 500 detailed repair guides and technical documents.

Training

Conducted technical training sessions and contributed to repair databases.

Certifications & Research

Certifications

  • ASE Master Technician Certification
  • Advanced Diagnostic Specialist
  • Hybrid/Electric Vehicle Systems
  • Performance Tuning Expert

Research & Community

Actively researches emerging technologies and contributes to automotive forums.

© 2025 Mercedes-Benz Specs. All rights reserved.

Privacy Policy Terms of Service