Mercedes R107 450SL Bumpers – U.S. Market Cars

In the early 1970's the U.S. Department of Transportation required upgraded bumpers to accept a 5 mph "tap" without any significant damage. As many will remember, these bumpers were pretty ugly and extended the length of the car significantly. 

Mounted on twin shocks, with rubber corners, rubber block overriders and rubber impact strips, they have now taken on a certain retro charm. 

Disassembling the bumper for restoration or repair is not complicated and is well worth it if you are wanting to do your car right. 

STEP 1
Both the front and rear bumper are held in place by two shocks mounted to the body of the car and by two mounting brackets on each side of the driver and passenger fenders (front and back). Start by detaching the side brackets. Next, simply remove the shock bolts and remove the bumper. NOTE: The bumpers are fairly heavy and awkward. I would recommend making this a two person job to avoid damaging the car or the bumper. 

STEP 2
Once the bumper(s) have been removed it is time for disassembly. My stainless steel caps were fairly dinged up, but purchasing new ones will cost you a considerable amount. With that knowledge at hand, I decided to have the old caps restored. You can either take the caps to a metal polishing shop who will beat out the dents and polish or, should you have the skill and tools to remove the dents it will save you a good bit of money. I chose the latter as I have metal working experience and once dent free, took the caps to be polished. I would recommend not attempting to polish at home unless you have professional equipment. Getting the mirror finish can not be achieved with consumer grade tools.

STEP 3
Next, remove the turn signal units to avoid any damage to them. Should you need one or two they are still available, as are just the lenses. The OEM unit is ULO and can be obtained from AutohausAZ

STEP 4
Now remove the shocks from the bumper. Remove the 4 bolts and extract shock along with two brackets and 2 rubber buffers.

STEP 5
With the shocks removed, the retaining nut for the overriders will be exposed—remove.

STEP 6
Remove the rubber bumper end caps by removing the 3 nuts and bolts. 

STEP 7
Now remove the rubber impact strip inserts. The front bumper will slide out, while the rear bumper will require the removal of one overrider/shock bracket to remove the impact strip.

STEP 8
At this stage the stainless steel bumper caps are now ready to be removed. Work carefully when removing to avoid bending the metal. Slightly lift up each tab to loosen the cap. Gently pry off cap from the back side (not the front lip). The tabs do not need to be opened up very much to get the cap off. 

Be mindful that you will be working around a rubber gasket and soft rubber sponge strip used to eliminate water and vibration.

With the bumper now disassembled and while the caps are off getting worked on, now is the time to clean and prep the bumpers. 

As you will see, the lower portion of the bumper is factory painted with a "rocker panel" stone guard. SEM makes a very good product for this application - Part No. 39793. Make sure to scrape, sand and clean very well before reapplying a new coating. Spray in even long strokes and do not apply in heavy coats. 

At this stage and once the bumper is dry for a good 24 hours at 75°F, the bumper can be reassembled and installed. Again, I would recommend this as a two person job.