Has anyone done repair on the aluminum bumper on 123's ? The rear bumper on my 84 300td (wagon) detatched from the bumper shock....overall, the bumper is in good condition...chrome is good, rubber good, and not much corrosion on inside surface. However, it is now just hanging from only one of the shock attachment points. I don't think it is possible to repair aluminum by welding. I will get a better look see this weekend, to see if I can attach with some type of steel bracket with bolts (hidden under rubber), but I don't know if this is feasible.

Any suggestions on repair? Any suggestions on where to find a replacement (wagon-specific rear bumper is hard to find)....any salvage yards in New England with decent 123 wagons?

Thanks,

Mark

__________________
1984 300TD Wagon, 407,800 mi (current daily driver)
1985 300DT Sedan, 330,000 mi (gone to that great autobahn in the sky)

What has most likely happened is the extruded channel on the inside of the aluminum bumper has corroded away. The shocks are secured in place with special bolts, these bolts have square flat heads which fit into the aluminum channel. The bumper shocks fit over the special bolts and washers and nuts secure the shocks in place. When the aluminum corrodes away from the edges of the extruded channel there is nothing to hold the special bolt's heads.

Replacing the bumper is one option, the other option is to remove the rubber impact strip and inside the channel the impact strip fits into, drill a pair of holes thru the aluminum bumper and through the shock’s mounting plates, bolt the shock to the bumper, and then you reinstall the rubber impact strip to cover the bolt heads. Because the bolt heads conflict with the back side of the rubber impact strip you can do a couple things either separately or in combination. Countersink the bolt head, this works best for slotted flat head type bolts, grind down the bolt head after installation to reduce its thickness, or carefully grind/melt out depressions in the back side of the rubber impact strips. With this done the impact strip will not show bumps where the bolt heads are.

When it comes time to reinstall the impact strip the warmer it is the better it will go! Do this with the bumper off with its channel facing upwards and where you can apply downward pressure while simultaneously moving the strip left and right working one side into the channel then the other, you’ll usually need a rubber mallet for the ends, warmth really helps when you get to the end sections

Thanks for the good information...I will try to pull apart and fix this weekend!
Mark

__________________
1984 300TD Wagon, 407,800 mi (current daily driver)
1985 300DT Sedan, 330,000 mi (gone to that great autobahn in the sky)

I have several bumpers out in the scrap pile that are in nice shape except for the impact shock coming off. I have never seen the bolts that you are referring to, the bumpers I have are bonded in some way. There is a square of aluminum around the outside of where it mounts on the bumper but no bolts. I would like to know what causes them to fail. I have tried to knock them off with a sledge hammer and mall but if they are on there is no simple knocking them off without a crash.

I do agree that if you wanted to fix one the best way would be to bolt it under the impact strip.

Anyone know how they are attached???

Robert

I would simply take it off and and take the pieces to your local welding shop, aluminum can be welded or get a used one.

__________________


1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"