W123 bumpers--how are they attached?

[herring]

I guess somebody banged into my rear bumper while I was parked--came back and it was at a bit of an odd angle. No damage to the surface, but when I looked underneath the steel bumper is essentially hanging onto square things protruding from the bumper shocks with some steel clips. Whatever held the bumper onto the rest of the square thing has let go.

Is this something where I could clean the surfaces and JBWeld it?

[Mustang_man298]

Originally Posted by herring

I guess somebody banged into my rear bumper while I was parked--came back and it was at a bit of an odd angle. No damage to the surface, but when I looked underneath the steel bumper is essentially hanging onto square things protruding from the bumper shocks with some steel clips. Whatever held the bumper onto the rest of the square thing has let go.

Is this something where I could clean the surfaces and JBWeld it?

I looked under mine, the bumper shock is held to the body with 2 bolts, the end of the shock appears to be some kind of plate that is captured between the bumper and the square plate that the end of the shock passes thru. The plate is them held to the bumper with 4 smaller bolts.

That bumper is the lifeline for the car and passengers, especially in the rear seat. I would be very hesitant to want to JB weld anything when it's just as easy and relatively inexpensive to replace the shock assembly. JB weld has no strength against the impact forces of a collision.

[charmalu]

I have an 85 bumper, and the black arms, I guess they are shocks. there are 2 L brackets about 4in long fasteded to the bumper top and botton. the square end of the shock slides behind these L brackets. then the bumper is held to the car with 3 studs & 17mm nuts.

I have a rear bumper off a 1980 300D mounted on the 85. the shocks are bolted to the bumper with 4 bolts. and then the three on the body.

The 80 bumper is 1/4 in thick. the 85 is really thin, guess MB`s weight reduction back in those days.

don`t use duct tape, bailing wire or JB weld. do it right. just go to PNP, that is where I got my 80 bumper.

Charlie ☺

[herring]

Ok, took the advice and went to a picknpull, paid $38 for the bumper (how bad did I get taken?). It's not perfect either but at least the brackets on the inside that hold the shock are still there and seem solid (there was only one W123 in the place so I couldn't be choosy). The chrome on the outside's not as shiny though

What are these things made out of anyway? Seems to be corroding into a white powder--is this zinc or something? If I wire-wheel and POR-15 the brackets is that going to stop the corrosion?

Also, the rubber on the bumper mount is better on this, but not perfect. Can I get new rubbers separately or do I have to buy whole shocks?

[charmalu]

The bumpers are made out of aluminium. I changed mine out because corosion was getting under the chrome and it was pealing off in big chunks.

The going price at PNP is about $40.00. I didn`t pay for mine, I was buying a whole lot of parts, and it didn`t get noticed. I was driving home and looking at the reciept when I noticed they didn`t charge me.

Next weekend will be 50% off

I don`t know if you can get new rubbers, I think you mean where the shock attaches to the bumper. maybe from the dealer.

charlie ☺

Originally Posted by charmalu

The bumpers are made out of aluminium.

Not on the W123.

[herring]

Well, this is outside my expertise. I just measured it, if it were flat it would be about 5' 8" long, 13" wide and 1/4" thick. I don't have a scale but people have posted elsewhere they're around 40 pounds. It did feel a little heavy for aluminum. Maybe someone who knows materials can venture a guess.

[herring]

Well, this is weird. I got a magnet off my fridge. It does stick to the bumper, kind of. I'd say about half as strong as it sticks to the fridge. Again, knowing next-to-nothing about metals, I'd guess it's an odd alloy that has a bit of iron in it, but it's not steel. Is there such a thing as an aluminum-iron alloy? I moved some ramps earlier today that are steel...definitely heavier in relation to size.

Anyway, there goes my idea of getting some bucks back from the recycler with my 40-pound aluminum bumper.

[t walgamuth]

I don't know the chemical properties of the bumpers but they seem to be sort of a cross between aluminum and steel. They don't rust and they are a lot stronger than plain aluminum. They are some sort of an alloy, I think. The old volvo bumpers are about the same stuff.

If you have ever tried drilling a hole in them you will know they are not ordinary aluminum.

Tom W

[Mustang_man298]

Originally Posted by t walgamuth

I don't know the chemical properties of the bumpers but they seem to be sort of a cross between aluminum and steel. They don't rust and they are a lot stronger than plain aluminum. They are some sort of an alloy, I think. The old volvo bumpers are about the same stuff.

If you have ever tried drilling a hole in them you will know they are not ordinary aluminum.

Tom W

Perhaps they are the T-66 alloy hardened aluminum, hard to drill and bend, but the weight and corrosion properties of aluminum? Mine appear to be aluminum or an alloy of it as well. Titanium I know has a lot of the same properties at first appearance as T-66, but I have my doubts they'd use that, & it scratches way too easily.

Herring- When you placed the magnet on the bumper, where was it? If you were near the mounting areas could it have been the shock magnetizing through the bumper possibly?

[TylerH860]

I bet the other car fared alot worse.

Backed into my garbage can last week. Almost airborne. No damage.

Try doing that with a plastic fantastic bumper.

[herring]

Originally Posted by Mustang_man298

Herring- When you placed the magnet on the bumper, where was it? If you were near the mounting areas could it have been the shock magnetizing through the bumper possibly?

I was at the very corner of the bumper, for that very reason. This was definitely not from the shock. There's SOME iron in that bumper, I'm sure of it.

[charmalu]

OK, I just went out and re checked my scientific research on the magnetic draw on the bumpers.
used the same magnet from my tool box. this thing is strong almost picks up my tool box.

I do detect a slight pull on the magnet checking in various places on the bumper. when I reach under the bumper and check the back side, not so noticeable.

so then went out back where I threw the old bumper with the chrome pealing off. where there is no chrome, there is no magnetic pull. where the chrome is peeled away from the bumper it sticks to the magnet. so I think the bumper is still Aluminium or an alloy.

Charlie ☺