336 Jump-starting, tow-starting and towing away U 423 / U 427 / U 430 / U 527 / U 530 Overview Spring-loaded parking brake cylinder for parking and service brake Breakdown assistance Releasing the spring-loaded parking brake cylinders manually ! Undo the release bolt with a maximum torque of 70 Nm. Do not use an impact wrench. You could otherwise damage the spring-loaded parking brake cylinder. X Use chocks to safeguard the vehicle against rolling away. X Unscrew release screw : of left and right- hand side spring-loaded parking brake cyl- inder ; as far as possible (release posi- tion).
Returning the spring-loaded parking brake cylinders to the operational condi- tion X Make sure that the J warning lamp in the instrument cluster is not lit. The vehicle's compressed air system has sufficient reservoir pressure. X Release the parking brake ( Y page 166). X Screw in and tighten release screw : of left and right-hand side parking brake cyl- inder ; (brake position). Tightening tor- que 40 to 50 Nm.