Mercedes-Benz Tow Bar Installation Guide

Vehicle Compatibility and Part Identification

Compatible Mercedes-Benz Models:

• GLC (X253): 06/2015 - 04/2019
• GLC AMG line (X253): 06/2015 - 04/2019
• GLC (X253): 05/2019 onwards
• GLC Coupe (C253): 06/2016 onwards
• EQC (N293): 05/2019 onwards

Key Tow Bar Part Numbers:

• MR66, MR66Q
• MR938, MR938S, MR938Q
• Main Part Number: 313 561 691 101-007
• Associated Part Numbers: 313 562 600 001, 313 561 600 001, 314 294 660 001, 913 183 630 121, 914 294 601 090, 933 096 621 001, 913 561 650 001, 933096650001

Specifications and Approvals:

• Approval Number: E11 55 R-01 10841
• Coupling Class: A 50-X
• D-Value: 13.3 kN (max)
• Nose Weight (S): 160 kg (max)
• Tow Bar Weight: 27 kg

Important Safety and Legal Information

General Guidelines:

• Adhere to all national regulations concerning the approval of vehicle attachments.
• Modifications or alterations to the tow bar are strictly prohibited and will invalidate the vehicle's operating license.
• Before installation, remove any insulating material or underbody protection from the vehicle's chassis where the tow bar will be mounted.
• The tow bar is designed exclusively for towing trailers and for use with load carriers. Any other use is forbidden.
• Parking Assist Systems: Vehicles equipped with parking assist sensors may experience malfunctions after tow bar installation if components obstruct the sensors. Adjust the sensor detection range or disable the system if required. For removable or pivoting ball hitches, ensure the ball is stowed correctly to prevent interference.
• The tow bar is a critical safety component and must be installed by qualified professionals only. Incorrect installation poses a severe accident risk.
• The German text within this manual is considered the binding version.
• Information is subject to change without notice.

Installation Procedure

Follow these steps carefully. Refer to accompanying diagrams for visual guidance.

Step 1: Vehicle Preparation

Access the rear of the vehicle. Diagrams illustrate the removal of bumper elements to expose the mounting points on the chassis.

Step 2: Mounting the Tow Bar Frame

Attach the main tow bar frame (labeled '1') to the vehicle's chassis using the provided brackets (labeled '2', '3', '4') and hardware.

Hardware for this step includes:

• 8x M12x1.75x40 bolts (Grade 8.8)
• 2x M8x1.25x50 bolts (Grade 8.8)
• 2x 12.4x30x3 washers
• 4x 13x24x2.5 washers
• 4x 8.4x16x1.6 washers
• 2x 12.5x20.5x1 washers
• Additional bolts: 2x M12 (size 10), 6x M12 (size 8), 2x M8 (size 8)

Step 3: Electrical System Connection

Connect the vehicle's electrical harness to the tow bar's socket. Important: This procedure is for Plug-In Hybrids ONLY. Consult the Mercedes Handbook for specific wiring details.

Step 4: Further Assembly and Wiring

Continue with electrical connections and mounting of additional components, referencing diagrams for placement of brackets (labeled '1', '2', '3').

Step 5: Bracket Installation

Securely mount the designated brackets ('1', '2', '3') to the vehicle's frame as indicated.

Step 6: Attaching Tow Bar Sections

Fasten the tow bar sections using M12 bolts and appropriate washers (e.g., 13x24x2.5).

Step 7: Electrical Socket Housing

Install the electrical socket housing and connect the wiring. Use specified bolts (e.g., M12x1.75x40) and washers (e.g., 12.4x30x3, 12.5x20.5x1).

Step 8: Final Tow Bar Securing

Attach the main tow bar assembly to the chassis using two M12x1.75x40 bolts on each side (securing points labeled '2' and '3').

Step 9: Torque Tightening

Ensure all bolts are tightened to the specified torque values:

• M12x1.75x40 bolts: 83 Nm
• M8x1.25x50 bolts: 24 Nm

Hardware involved: M8 bolts with 8.4x16x1.6 washers, M12x1.75x40 bolts, M8x1.25x50 bolts.

Step 10: Bumper Modification

Diagrams provide instructions for modifying the vehicle's rear bumper. This may involve cutting specific sections. Dimensions such as 45mm, 80mm, 90mm, 180mm, and reference points YO and "a" are indicated. A note advises that the exact procedure may vary between vehicle versions.

An "Inside view" of the bumper area is shown for clarity.

Step 11: Tow Ball and Electrical Connector Assembly

Assemble the tow ball and connect the electrical wiring. Torque specification for 10.9 M12 x 1.75 x 110mm bolts is 117 Nm.

Hardware used: 10.9 M12 x 1.75 x 110mm bolts, M12 bolts, 2x M12x1.75x110 bolts.

Step 12: Reassembly of Bumper

Reinstall the vehicle's bumper components after the tow bar installation is complete.

Technical Data and Installation Declaration

D-Value Calculation: The D-value, crucial for determining the maximum towing capacity, is calculated using the formula: D = (T x C) / (T + C) x 0.00981, where T is the vehicle's Gross Vehicle Mass and C is the vehicle's maximum towing capacity.

Installation Declaration: A formal declaration is provided for the installer to confirm that the tow bar has been fitted correctly according to the manufacturer's specifications and that the vehicle owner has been informed about the proper use and maintenance of the tow bar.