Mercedes-Benz Vehicle Models Mercedes A-Class 2012-2018 Torque Specifications
Mercedes-Benz Vehicle Models Mercedes A-Class 2012-2018

Mercedes-Benz Vehicle Models Mercedes A-Class 2012-2018 Torque Specifications

Complete Mercedes-Benz Vehicle Models Mercedes A-Class 2012-2018 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

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Torque Calculator

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1.5l I4 Engine

Torque specifications for 1.5L-I4 Engine

Cylinder Head

1

Cylinder Head Bolts

M12 x 1.5
Torque Specification
18 ft-lbs (25 N·m)
2

Valve Cover Bolts

M8 x 1.25
Torque Specification
7 ft-lbs (10 N·m)

Engine Block

1

Main Bearing Bolts

M14 x 1.5
Torque Specification
18 ft-lbs (25 N·m)
2

Oil Pan Bolts

M10 x 1.25
Torque Specification
7 ft-lbs (10 N·m)

Crankshaft and Camshaft

1

Flywheel Bolts

M16 x 1.5
Torque Specification
44 ft-lbs (60 N·m)
2

Camshaft Sprocket Bolt

M14 x 1.5
Torque Specification
44 ft-lbs (60 N·m)
3

Crankshaft Pulley/Harmonic Balancer Bolt

M18 x 1.5
Torque Specification
81 ft-lbs (110 N·m)

Valve Train

1

Rocker Arms/Shafts Bolts

M10 x 1.25
Torque Specification
15 ft-lbs (20 N·m)

Fuel System

1

Fuel Injector Bolts

M8 x 1.25
Torque Specification
7 ft-lbs (10 N·m)
2

Fuel Rail Bolts

M10 x 1.25
Torque Specification
7 ft-lbs (10 N·m)

Exhaust System

1

Exhaust Manifold/Headers Bolts

M12 x 1.5
Torque Specification
33 ft-lbs (45 N·m)
2

Exhaust Manifold/Headers to Cylinder Head Bolts

M10 x 1.25
Torque Specification
18 ft-lbs (25 N·m)

Engine Mounting

1

Engine Mounting Bolts

M14 x 1.5
Torque Specification
40 ft-lbs (55 N·m)
Important Notes
Estimated value based on general industry standards.

Sensors and Accessories

1

Crankshaft Position Sensor Bolt

M8 x 1.25
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Estimated value based on general industry standards.
2

Camshaft Position Sensor Bolt

M8 x 1.25
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Estimated value based on general industry standards.

Oil Pump

1

Oil Pump Bolts

M12 x 1.5
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Estimated value based on general industry standards.

1.6l I4 Engine

Torque specifications for 1.6L-I4 Engine

Cylinder Head

1

Cylinder Head Bolts

M10 x 1.25
Torque Specification
1. 18 ft-lbs (25 N·m) 2. 90°
Important Notes
Follow the manufacturer's torque sequence for proper sealing. Estimated bolt size based on typical cylinder head bolts.
2

Valve Cover Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (10 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
18 ft-lbs (25 N·m)
Important Notes
Ensure proper alignment of the crankshaft and bearings before tightening.
2

Connecting Rod Nuts

M8 x 1.25
Torque Specification
22 ft-lbs (30 N·m)
Important Notes
Ensure proper alignment of the connecting rod and crankshaft journal.

Timing System

1

Timing Belt/Chain Tensioner Bolt

M8 x 1.25
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
Ensure proper tension of the timing belt/chain before tightening.
2

Camshaft Sprocket Bolt

M12 x 1.5
Torque Specification
44 ft-lbs (60 N·m)
Important Notes
Ensure proper alignment of the camshaft sprocket before tightening.

Oil System

1

Oil Pan Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Ensure the oil pan gasket is properly seated before tightening.
2

Oil Drain Plug Bolt

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

Intake And Exhaust

1

Intake Manifold Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Ensure the intake manifold gasket is properly seated before tightening.
2

Exhaust Manifold Bolts

M8 x 1.25
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Ensure the exhaust manifold gasket is properly seated before tightening.

2.0l I4 Engine

Torque specifications for 2.0L-I4 Engine

Cylinder Head and Valvetrain

1

Cylinder Head Bolts

M12 x 1.5
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
Ensure proper torque sequence to avoid damaging the cylinder head or engine block.
2

Valve Cover Bolts

M8 x 1.25
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Ensure proper torque to avoid damaging the valve cover or cylinder head.

Engine Block and Crankshaft

1

Main Bearing Bolts

M14 x 1.5
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
Ensure proper torque sequence to avoid damaging the engine block or crankshaft.
2

Crankshaft Pulley/Harmonic Balancer Bolt

M16 x 1.5
Torque Specification
81 ft-lbs (110 N·m)
Important Notes
Ensure proper torque to avoid damaging the crankshaft or pulley/balancer.

Camshaft and Timing System

1

Camshaft Sprocket Bolt

M12 x 1.5
Torque Specification
44 ft-lbs (60 N·m)
Important Notes
Ensure proper torque to avoid damaging the camshaft or sprocket.
2

Timing Belt/Chain Tensioner Bolt

M10 x 1.25
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
Ensure proper torque to avoid damaging the timing belt/chain or tensioner.

Engine Mounts and Exhaust System

1

Engine Block-to-Engine Mount Bolts

M12 x 1.5
Torque Specification
44 ft-lbs (60 N·m)
Important Notes
Estimated value. Ensure proper torque to avoid damaging the engine block or engine mounts.
2

Exhaust Manifold/Headers Bolts

M10 x 1.25
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Ensure proper torque to avoid damaging the exhaust manifold/header or cylinder head.

Oil System

1

Oil Pan Bolts

M8 x 1.25
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Ensure proper torque to avoid damaging the oil pan or engine block.
2

Oil Filter Housing Bolt

M10 x 1.25
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Estimated value. Ensure proper torque to avoid damaging the oil filter housing or engine block.

Spark Plugs and Ignition System

1

Spark Plugs

M14 x 1.25
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
Ensure proper torque to avoid damaging the spark plugs or cylinder head.

7g Dct Transmission

Torque specifications for 7g Dct Transmission

Transmission Mounting

1

Transmission Mounting Bolts

M12 x 1.5
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
These bolts secure the transmission to the engine block or transmission tunnel.

Transmission Oil Pan

1

Transmission Oil Pan Bolts

M8 x 1.25
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
These bolts secure the oil pan to the transmission.

Transmission Fluid System

1

Transmission Drain and Fill Plugs

M14 x 1.5
Torque Specification
29 ft-lbs (40 N·m)
Important Notes
These plugs allow for the draining and filling of transmission fluid.
2

Transmission Fluid Drain/Fill Plug

M14 x 1.5
Torque Specification
29 ft-lbs (40 N·m)
Important Notes
This plug is specific to the transmission fluid system.

Transmission Case and Cover

1

7G-DCT Transmission Case Bolts

M14 x 1.5
Torque Specification
44 ft-lbs (60 N·m)
Important Notes
These bolts secure the transmission case and cover. Estimated value based on industry standards.

Clutch Pack

1

7G-DCT Clutch Pack Bolts

M10 x 1.25
Torque Specification
22 ft-lbs (30 N·m)
Important Notes
These bolts secure the clutch pack to the transmission case. Estimated value based on industry standards.

Gearbox Mounting

1

7G-DCT Gearbox Mounting Bolts

M16 x 1.5
Torque Specification
52 ft-lbs (70 N·m)
Important Notes
These bolts secure the gearbox to the transmission case. Estimated value based on industry standards.

Body

Torque specifications for Body

Suspension

1

Strut/Shock Absorber Mounting Bolts

M14 x 1.5
Torque Specification
52 ft-lbs (70 N·m)
Important Notes
Secure the strut/shock absorbers to the vehicle's body.
2

Control Arm Bolts

M16 x 1.5
Torque Specification
67 ft-lbs (90 N·m)
Important Notes
Connect the control arms to the body, maintaining proper suspension geometry and stability.
3

Ball Joint Nut

M12 x 1.25
Torque Specification
48 ft-lbs (65 N·m)
Important Notes
Secure the ball joints to the control arms, allowing for smooth suspension movement and stability.
4

Tie Rod End Nut

M10 x 1.25
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Connect the tie rods to the steering gear, maintaining proper toe alignment and steering stability.

Steering

1

Steering Gear/Rack Bolts

M14 x 1.5
Torque Specification
81 ft-lbs (110 N·m)
Important Notes
Secure the steering gear to the body, ensuring proper steering alignment and stability.

Braking

1

Brake Caliper Bolts

M14 x 1.5
Torque Specification
81 ft-lbs (110 N·m)
Important Notes
Secure the brake calipers to the brake rotor or hub, maintaining proper brake function and safety.
2

Brake Caliper Mounting Bracket Bolts

M12 x 1.25
Torque Specification
81 ft-lbs (110 N·m)
Important Notes
Secure the brake caliper mounting bracket to the body, ensuring proper brake alignment and stability.

Body Panels

1

Body Panel Fasteners (e.g., Hood, Trunk Lid, Doors)

M8 x 1.25
Torque Specification
12 ft-lbs (16 N·m)
Important Notes
Estimated value. Secure the body panels to the vehicle's body, ensuring proper panel alignment and security.

Bumpers and Trim

1

Bumper Mounting Bolts

M10 x 1.25
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Estimated value. Secure the bumper to the body, ensuring proper bumper alignment and stability.
2

Roof Rack Mounting Bolts (if equipped)

M10 x 1.25
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Estimated value. Secure the roof rack to the body, ensuring proper roof rack stability and security.
3

Side Mirror Mounting Bolts

M8 x 1.25
Torque Specification
12 ft-lbs (16 N·m)
Important Notes
Estimated value. Secure the side mirrors to the body, ensuring proper mirror alignment and stability.

Brakes

Torque specifications for Brakes

Brake Caliper and Mounting

1

Brake Caliper Bolts

M12 x 1.5
Torque Specification
81 ft-lbs (110 N·m)
2

Brake Caliper Mounting Bracket Bolts

M12 x 1.5
Torque Specification
81 ft-lbs (110 N·m)

Brake Disc/Drum and Rotor

1

Brake Disc/Drum Retaining Bolts

M10 x 1.25
Torque Specification
81 ft-lbs (110 N·m)
2

Brake Rotor Bolts (if applicable)

M8 x 1.25
Torque Specification
17.5 ft-lbs (23.75 N·m)
Important Notes
Estimated value. Not all brake systems use rotor bolts.

Wheel and Hub

1

Wheel Lug Nuts

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

Brake Master Cylinder and Booster

1

Brake Master Cylinder Mounting Bolts

M10 x 1.25
Torque Specification
17.5 ft-lbs (23.75 N·m)
Important Notes
Estimated value.
2

Brake Booster Mounting Bolts

M10 x 1.25
Torque Specification
17.5 ft-lbs (23.75 N·m)
Important Notes
Estimated value.

ABS Module

1

ABS Module Mounting Bolts

M8 x 1.25
Torque Specification
12.5 ft-lbs (16.9 N·m)
Important Notes
Estimated value.

Drivetrain

Torque specifications for Drivetrain

Engine Mounting

1

Engine Mounting Bolts

M12 x 1.5
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Estimated value based on general industry standards.

Transmission Mounting

1

Transmission Mounting Bolts

M12 x 1.5
Torque Specification
33 ft-lbs (45 N·m)
2

Transmission Crossmember Bolts

M12 x 1.5
Torque Specification
44 ft-lbs (60 N·m)
Important Notes
Estimated value based on general industry standards.

Transmission Oil Pan

1

Transmission Oil Pan Bolts

M8 x 1.25
Torque Specification
7 ft-lbs (10 N·m)

Transmission Drain And Fill

1

Transmission Drain and Fill Plugs

M12 x 1.5
Torque Specification
29 ft-lbs (40 N·m)

Differential Drain And Fill

1

Differential Drain and Fill Plug

M12 x 1.5
Torque Specification
29 ft-lbs (40 N·m)

Driveshaft Center Bearing

1

Driveshaft Center Bearing Bolts

M12 x 1.5
Torque Specification
29 ft-lbs (40 N·m)
Important Notes
Estimated value based on general industry standards.

Axle Shaft Retaining

1

Axle Shaft Retaining Bolts

M12 x 1.5
Torque Specification
44 ft-lbs (60 N·m)
Important Notes
Estimated value based on general industry standards.

Flywheel

1

Flywheel Bolts

M12 x 1.5
Torque Specification
44 ft-lbs (60 N·m)

Drive Axle Half Shaft

1

Drive Axle/Half Shaft Bolts

M12 x 1.5
Torque Specification
44 ft-lbs (60 N·m)

Cv Joint Axle Nut

1

CV Joint/Axle Nut

M20 x 1.5
Torque Specification
181 ft-lbs (245 N·m)

Propeller Drive Shaft

1

Propeller/Drive Shaft Bolts

M12 x 1.5
Torque Specification
44 ft-lbs (60 N·m)

Electrical

Torque specifications for Electrical

Alternator And Starter Motor

1

Alternator Mounting Bolts

M12 x 1.5
Torque Specification
18 ft-lbs (25 N·m)
2

Starter Motor Mounting Bolts

M14 x 1.5
Torque Specification
33 ft-lbs (45 N·m)

Battery And Terminals

1

Battery Terminal Nuts

M10 x 1.5
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Estimated value, as 'hand tight' is not a specific torque value.

Ignition And Fuel System

1

Ignition Coil Mounting Bolts

M10 x 1.5
Torque Specification
1. 10 ft-lbs (14 N·m) 2. 12 ft-lbs (16 N·m)
Important Notes
Estimated values based on general industry guidelines.
2

Spark Plug Wire Retainer Bolts

M8 x 1.25
Torque Specification
1. 5 ft-lbs (7 N·m) 2. 7 ft-lbs (10 N·m)
Important Notes
Estimated values based on general industry guidelines.
3

Fuel Pump Electrical Connector Bolts

M6 x 1.0
Torque Specification
1. 5 ft-lbs (7 N·m) 2. 7 ft-lbs (10 N·m)
Important Notes
Estimated values based on general industry guidelines.

A/C Compressor Electrical Connector

1

A/C Compressor Electrical Connector Bolts

M6 x 1.0
Torque Specification
1. 5 ft-lbs (7 N·m) 2. 7 ft-lbs (10 N·m)
Important Notes
Estimated values based on general industry guidelines.

Emissions Sensors

Torque specifications for Emissions_sensors

Exhaust Manifold Headers

1

Exhaust Manifold/Headers Bolts

M10 x 1.25
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Ensure proper torque sequence to avoid warping the manifold.
2

Exhaust Manifold/Headers to Cylinder Head Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
Ensure proper torque sequence to avoid warping the manifold.

Exhaust Pipe Connections

1

Exhaust Pipe to Exhaust Manifold/Headers Bolts

M10 x 1.25
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Ensure gasket is properly seated before tightening.
2

Catalytic Converter to Exhaust Pipe Bolts

M10 x 1.25
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Ensure gasket is properly seated before tightening.

Emissions Control Components

1

EGR Valve Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Ensure gasket is properly seated before tightening.
2

Oxygen Sensor (Lambda Sensor) Mounting

M12 x 1.25
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Estimated value based on similar components. Ensure proper alignment to avoid damaging the sensor.
3

NOx Sensor Mounting

M12 x 1.25
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Estimated value based on similar components. Ensure proper alignment to avoid damaging the sensor.
4

DPF (Diesel Particulate Filter) Mounting Bolts

M10 x 1.25
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Ensure proper torque sequence to avoid warping the DPF housing.

Exhaust

Torque specifications for Exhaust

Exhaust Manifold Headers

1

Exhaust Manifold/Headers to Cylinder Head Bolts

M10 x 1.25
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Ensure proper sequence is followed to avoid warping the manifold or headers.

Exhaust Pipe Connections

1

Exhaust Pipe to Exhaust Manifold/Headers Bolts

M10 x 1.25
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Ensure gasket is properly seated before tightening.
2

Catalytic Converter to Exhaust Pipe Bolts

M10 x 1.25
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Ensure gasket is properly seated before tightening.
3

Muffler to Exhaust Pipe Bolts

M10 x 1.25
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Ensure gasket is properly seated before tightening.

Heat Shield And Hangers

1

Exhaust Heat Shield Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Estimated value based on typical heat shield bolt sizes.
2

Exhaust Hanger Bolts

M8 x 1.25
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Estimated value based on typical hanger bolt sizes.

Oxygen Sensor

1

Oxygen Sensor (O2 Sensor) Mounting Bolts

M12 x 1.5
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Ensure sensor is properly seated before tightening.

Exhaust Flange

1

Exhaust Flange Bolts

M10 x 1.25
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Ensure gasket is properly seated before tightening.

Fuel

Torque specifications for Fuel

Fuel Rail and Injectors

1

Fuel Rail Bolts

M8 x 1.25
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Proper torque is essential to prevent fuel leaks and maintain engine performance.
2

Fuel Injector Bolts

M8 x 1.25
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Proper torque is crucial to prevent fuel leaks and maintain engine efficiency.
3

Fuel Injector Hold-Down Clamp Bolts

M6 x 1.0
Torque Specification
6 ft-lbs (8 N·m)
Important Notes
Estimated torque value based on general industry guidelines. Proper torque is crucial to prevent fuel leaks and maintain engine efficiency.

Fuel Pump and Filter

1

Fuel Pump Mounting Bolts

M10 x 1.5
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Proper torque is essential to prevent fuel pump failure and maintain engine performance.
2

Fuel Filter Bolt/Nut

M12 x 1.75
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
Proper torque is essential to prevent fuel filter failure and maintain engine efficiency.
3

Fuel Pump Electrical Connector Bolts

M6 x 1.0
Torque Specification
6 ft-lbs (8 N·m)
Important Notes
Estimated torque value based on general industry guidelines. Proper torque is essential to prevent electrical connection failure and maintain engine performance.

Fuel Tank and Filler Neck

1

Fuel Tank Strap Bolts

M12 x 1.75
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
Proper torque is essential to prevent fuel tank damage and maintain vehicle safety.
2

Fuel Filler Neck Bolts

M8 x 1.25
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Proper torque is essential to maintain fuel tank integrity and prevent fuel spills.

Fuel Pressure Regulator

1

Fuel Pressure Regulator Mounting Bolts

M8 x 1.25
Torque Specification
11 ft-lbs (15 N·m)
Important Notes
Estimated torque value based on general industry guidelines. Proper torque is essential to ensure the regulator is securely attached and functioning correctly.

Hvac

Torque specifications for Hvac

Ac Compressor

1

A/C Compressor Mounting Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
Ensure bolts are tightened in a crisscross pattern to evenly distribute pressure.

Ac Lines

1

A/C Line Fittings

M10 x 1.25
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
Use a torque wrench to avoid over-tightening, which can damage O-rings.

Cooling System

1

Thermostat Housing Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Ensure the thermostat is properly seated before tightening bolts.
2

Water Pump Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Ensure the water pump gasket is properly seated before tightening bolts.

Heater Core

1

Heater Core Inlet/Outlet Pipe Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Estimated value based on similar coolant line connections.

Blower Motor

1

Blower Motor Housing Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Estimated value based on similar housing fasteners.

Evaporator Core

1

Evaporator Core Mounting Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Estimated value based on similar mounting bolts.

Hvac Controls

1

HVAC Control Panel Mounting Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Estimated value based on similar panel fasteners.

Suspension

Torque specifications for Suspension

Strut/Shock Absorber Mounting

1

Strut/Shock Absorber Mounting Bolts

M14 x 1.5
Torque Specification
52 ft-lbs (70 N·m)
Important Notes
Proper torque is essential to maintain ride comfort and handling.

Control Arm Mounting

1

Control Arm Bolts

M16 x 1.5
Torque Specification
67 ft-lbs (90 N·m)
Important Notes
Correct torque ensures proper tracking and alignment of the wheels.
2

Upper Control Arm Bushing Bolts

M12 x 1.25
Torque Specification
40 ft-lbs (55 N·m)
Important Notes
Estimated value. Proper torque is essential to ensure smooth suspension movement and prevent wear.
3

Lower Control Arm Bolt

M18 x 1.5
Torque Specification
75 ft-lbs (100 N·m)
Important Notes
Correct torque is essential to maintain ride comfort and handling.

Ball Joint and Tie Rod End

1

Ball Joint Nut

M14 x 1.5
Torque Specification
48 ft-lbs (65 N·m)
Important Notes
Proper torque prevents damage to the joint and ensures smooth suspension operation.
2

Tie Rod End Nut

M12 x 1.25
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Correct torque prevents play and ensures precise steering response.

Sway Bar and Stabilizer Link

1

Sway Bar Link Nut

M12 x 1.25
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Proper torque prevents sway bar movement and ensures stable handling.
2

Stabilizer Link Bolts

M10 x 1.25
Torque Specification
30 ft-lbs (40 N·m)
Important Notes
Estimated value. Correct torque prevents play and ensures stable handling.

Steering Gear/Rack Mounting

1

Steering Gear/Rack Bolts

M16 x 1.5
Torque Specification
81 ft-lbs (110 N·m)
Important Notes
Correct torque prevents play and maintains precise steering control.

Coil Spring Insulator

1

Coil Spring Insulator Bolts

M10 x 1.25
Torque Specification
25 ft-lbs (35 N·m)
Important Notes
Estimated value. Proper torque is necessary for smooth suspension operation.

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 tools are recommended for applying torque?

Use a calibrated torque wrench to ensure accurate and consistent torque application. Refer to Mercedes technical specifications for specific torque wrench requirements.

Q2

Can I use threadlocker on all bolts?

No, threadlocker should only be used on specified bolts as per Mercedes guidelines. Incorrect usage can damage the threads or affect torque accuracy.

Q3

How often should torque values be rechecked?

Follow Mercedes recommendations for periodic torque checks. Typically, critical bolts should be rechecked after major maintenance or suspension work.

Q4

What are the consequences of over-tightening bolts?

Over-tightening can cause bolt stretching, thread damage, or component deformation. Always adhere to specified torque values and use a proper torque wrench.

Q5

Can I substitute bolts with similar-looking ones?

No, it IS crucial to use only genuine Mercedes bolts or those approved by the manufacturer. Using incorrect bolts may compromise torque specifications and safety.

Q6

How do I identify torque-critical bolts?

Mercedes service manuals and specifications will typically indicate torque-critical bolts. Look for specific symbols or markings on bolt heads or components.

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
Technical Service Bulletins

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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.

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