MB Medic Mercedes-Benz Repair Guides, Service, How To DIY
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In this guide (5 sections)
In this tutorial, we will show you how to replace the fender on a Mercedes-Benz R-Class, also known as the W251 chassis. It has several trims, including R350, R320, and R500. This guide applies to model years 2006 through 2012. The procedure below is the removal, which is ten minutes of bolts once you know where they are, and the two sections after it are the parts that actually decide whether the finished car looks right: the paint code, and the panel gaps.
Instructions
- Remove the wheel’s inner liner. Remove plastic retainers.
- Remove the 10mm bolts that hold the inner liner in place.
- Lower the side skirt.Â
- Remove the two bolts holding the fender in place. These two screws are located behind the side skirt. There is no need to remove the side skirt; just loosen it enough to access the bolts.
- Remove two 10 mm bolts at the A-pillar. The plastic cover needs to be removed. Once you remove the plastic cover, you will see the bolts. The upper bolt can be removed with the door open, and the lower bolt can be accessed from the wheel well.
- Remove three 10mm bolts at the top of the fender.Â
- Remove one T20 screw where the fender and front bumper meet.Â
- Pull the bumper release towards the back of the car.Â
- Remove the fender from the R Class.
- Install the new fender and do the reverse procedure.
Before you order the fender
Get the paint code first, because the panel is the cheap part
A replacement fender arrives primed or in whatever color the donor car was, and on a silver or a metallic black R-Class a shade that is nearly right looks worse than a dent. The panel itself is not what makes this job expensive, the paintwork is, so the color code is the first thing to sort out and the last thing you want to guess.
Mercedes puts a three digit paint number on the vehicle data sticker, with or without a letter prefix, often beside the word FARBE. Look in the driver’s door jamb first on later cars, then the data plate above the radiator on older ones, then a smaller build label under the hood near the strut tower or firewall, then the spare wheel well or trunk lid. If you find two codes together, the first is the body color and the second is the interior. Our Mercedes paint code guide has the locations and the code list.
Worth deciding honestly before you buy anything: a dented steel fender can often be pulled and filled for less than a painted replacement, but a creased one, a torn one, or one rusting along the bottom edge is a replacement. The deciding factor is almost always the cost of paint, not the cost of the panel.
A replacement fender arrives primed or in whatever color the donor car was, and on a silver or a metallic black R-Class a shade that is nearly right looks worse than a dent. The panel itself is not what makes this job expensive, the paintwork is, so the color code is the first thing to sort out and the last thing you want to guess.
Mercedes puts a three digit paint number on the vehicle data sticker, with or without a letter prefix, often beside the word FARBE. Look in the driver’s door jamb first on later cars, then the data plate above the radiator on older ones, then a smaller build label under the hood near the strut tower or firewall, then the spare wheel well or trunk lid. If you find two codes together, the first is the body color and the second is the interior. Our Mercedes paint code guide has the locations and the code list.
Worth deciding honestly before you buy anything: a dented steel fender can often be pulled and filled for less than a painted replacement, but a creased one, a torn one, or one rusting along the bottom edge is a replacement. The deciding factor is almost always the cost of paint, not the cost of the panel.
The step most people get wrong
Hang the fender loose and set the gaps before you tighten anything
The bolt holes in a fender are slots, not round holes, and that is deliberate. The fender is what sets the panel gaps to the door, the hood and the front bumper, and those gaps are adjustable by a few millimeters in every direction.
So when the new one goes on, start every bolt but leave them all finger tight. Close the door and the hood, stand back, and work the panel until the gap along the door edge is even from top to bottom and the hood line matches the other side. Then tighten from the A pillar end forward, checking the gaps again as you go, because the panel will walk slightly as the bolts pull up.
If you torque the bolts down in the order you removed them, the gaps end up wherever the panel happened to be sitting, and no amount of pushing afterwards will move it. That is the difference between a fender that looks factory and one that announces itself from across the parking lot.
Two smaller things: order new plastic retainers for the inner liner before you start, because they break on removal rather than coming out intact, and check for a connector at the side marker or turn signal repeater and unplug it before you pull the panel away.
The bolt holes in a fender are slots, not round holes, and that is deliberate. The fender is what sets the panel gaps to the door, the hood and the front bumper, and those gaps are adjustable by a few millimeters in every direction.
So when the new one goes on, start every bolt but leave them all finger tight. Close the door and the hood, stand back, and work the panel until the gap along the door edge is even from top to bottom and the hood line matches the other side. Then tighten from the A pillar end forward, checking the gaps again as you go, because the panel will walk slightly as the bolts pull up.
If you torque the bolts down in the order you removed them, the gaps end up wherever the panel happened to be sitting, and no amount of pushing afterwards will move it. That is the difference between a fender that looks factory and one that announces itself from across the parking lot.
Two smaller things: order new plastic retainers for the inner liner before you start, because they break on removal rather than coming out intact, and check for a connector at the side marker or turn signal repeater and unplug it before you pull the panel away.
If this fender came off in a collision
Scan the airbag system before you call the job finished
Bodywork is only half of a front end repair. An impact hard enough to take out a fender is often hard enough for the airbag control unit to log a crash record, and that record does not clear itself when the panel is straight. Nor do the front impact sensors, which live in the front of the car and get damaged or disconnected in exactly the sort of hit that bends a fender.
The symptom is an SRS or airbag warning light that stays on after a perfect body repair, and it is not cosmetic. A control unit holding a crash record will not deploy properly again.
So scan the SRS system before you put the new panel on and again afterwards.
The YOUCANIC UCAN-II Pro reads the Mercedes airbag control unit rather than only engine codes, which is where this fault lives and exactly what a basic code reader cannot see.
If the unit has stored a crash record, a dealer sells you a new airbag control unit that then has to be coded to the car. Module Medics perform SRS crash data resets on the original unit and return it, which keeps the car’s own coding and costs a fraction of a replacement. They also reset pyrotechnic seat belt retractors, which lock after an impact and are the other thing people discover weeks later.
Bodywork is only half of a front end repair. An impact hard enough to take out a fender is often hard enough for the airbag control unit to log a crash record, and that record does not clear itself when the panel is straight. Nor do the front impact sensors, which live in the front of the car and get damaged or disconnected in exactly the sort of hit that bends a fender.
The symptom is an SRS or airbag warning light that stays on after a perfect body repair, and it is not cosmetic. A control unit holding a crash record will not deploy properly again.
So scan the SRS system before you put the new panel on and again afterwards.
The YOUCANIC UCAN-II Pro reads the Mercedes airbag control unit rather than only engine codes, which is where this fault lives and exactly what a basic code reader cannot see.
If the unit has stored a crash record, a dealer sells you a new airbag control unit that then has to be coded to the car. Module Medics perform SRS crash data resets on the original unit and return it, which keeps the car’s own coding and costs a fraction of a replacement. They also reset pyrotechnic seat belt retractors, which lock after an impact and are the other thing people discover weeks later.
Related reading
Before you buy parts, scan every control module, not just the engine. It shows the root fault behind the warning lights and tells you whether the problem is still active. See how to do a full health check.
