The service brake uses brake shoes that are within the rear wheel hubs and make no use of the brake pads and rotors. The service brake should be on maximum on the 6th click. There are two points of adjustment. The easiest and most usual is the service brake cable adjustment in the middle of the car, I confess I draw blank here but I think there is an access panel under the rear seat (as per the C class) that permits handbrake cable adjustment without having to do it from under the car. If the service brake cannot be adjusted enough at the handbrake coupling then the each rear hub will need adjusting. First slacken the hand brake coupling - this will allow greater adjustment in future when the shoes have been adjusted. Start with the Left rear wheel. Remove one wheel nut only but leave the wheel on and jack up the car at the back left until the left wheel is free to rotate. Position the empty wheel nut hole at the 1 o'clock position and shine a powerful torch into the hole. Towards the top edge of the hole you should see the toothed edge of the service brake adjustment wheel - you may have to rotate the road wheel backwards and forwards a few degrees to locate it. Insert a screw driver and click the adjustment teeth upwards, one tooth at a time. Keep doing this until the road wheel rotation is stiff, then take about 5 clicks downwards to release the brake shoe contact. Lower the car, put back the removed wheel nut and tighten. Remove a wheel nut from the right road wheel and lift the car until it can freely rotate. Position the nut hole at about 11 O'clock until you can see the adjustment teeth. This time the teeth need to be clicked downwards (note this important difference) until the rotation is hindered. Then click upwards for 5 teeth to release the shoes. When both sides have been adjusted the remaining fine adjustment can be done with the service brake cable adjustment in the middle of the car. The brake should begin to come on at about 3 clicks and be very stiff at 6 clicks with almost all your effort to get to 7 clicks. Unless you drive around with service brake left on the shoes, with occasional adjustment, should last the life of a car. If no amount of adjustment sorts out the service brake the shoes may need replacing and I would leave this to the Mercedes guys as the job is a bit of pain.
Good, I hope, regardless what the dash board lights are saying, that the service parking brake now feels good and meaty.
Does the service "P" light go off when you release it normally? and does it go off now?. The brake switch indicating engagement and release is towards the top of the foot brake pedal arm. It is simple contact device but can at times become dislodged from its mounting preventing the system from detecting whether the brake is engaged or not and may, as a result cause a 'malfunction' signal. Check that this switch looks OK. If you are confident that the service brake is now good take the vehicle to a Mercedes and ask them to clear the error. If a malfunction has been corrected one way to clear the error from the ECU memory is to disconnect the negative terminal to the cars battery for ten minutes. Note that it is important that all ancillary devices, radio etc are switched off before disconnecting the battery. If any security codes are stored make sure you have copies as you may need them to gain access when the battery is reconnected
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Hello I have adjusted the park brakes as you have described but the malfunction illumination message in the dashboard remains on "Service brake visit workshop" How do I cancel this message.
Thank you problem sorted
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