1.25" receiver hitch on my 1985 300D - PeachParts Mercedes-Benz Forum

BillGrissom · #1 09-20-2016, 11:39 PM

Just posting as an idea for others, not to upset people, and not trying to steal anyone's thunder if they pioneered this before. I ran across a rare flat-bar trailer hitch on a 300D at PickNPull, so grabbed for ~$5. The ball was so rusted I couldn't get it off with my biggest pipe wrench. The bar was bent slightly down, so pressed it straight w/ my shop press before cutting. I find the newer receiver style more useful, and have one on my 2 minivans (1.25" & 2" types), so already have attachments - bike rack, extender platform (hauling a bloody deer). I bought a 1.25" adapter on sale at Harbor Freight (~$12) and hack-sawed to fit the flat-bar, then welded w/ my cheap HF wire-flux welder. A 2" receiver is more universal, but would extend past the flat-bar and seems excessive for the W123.

When attaching to the rear aluminum bumper, I noticed a crack which you can see at the right (not me). At least I didn't drill holes in a pristine bumper. I may add a steel reinforcing plate later, or replace the whole bumper. Interestingly, I noticed that my front bumper has a factory steel backer. It is a replacement from when I broke one shock mount in flat-bar towing it. The original 1985 front bumper doesn't have that backer.

The hitch mounts on a W123 seem weak - aluminum bumper and thin sheet-metal of tire well. So, just joking about the deer and will probably only use a bike rack. I certainly won't be towing any concrete trailers. I did weld a steel ring from Ace to attach safety chains, in case I ever tow a small trailer.

t walgamuth · #2 09-21-2016, 06:14 AM

With the rear bumpers liable to fall off just from their own weight, I'd never recommend attaching any sort of hitch on them.

yuke · #3 09-21-2016, 06:47 AM

Looks pretty solid to me I kind of have same setup on my 85 300sd with a 2" receiever I've towed a u-haul many miles with it and have an aluminum carrier I can fit on if I want. Mine is holding up fine.

t walgamuth · #4 09-21-2016, 08:05 AM

I'm glad its working for you.

BillGrissom · #5 09-21-2016, 10:22 AM

Quote:

Originally Posted by t walgamuth

With the rear bumpers liable to fall off just from their own weight, I'd never recommend attaching any sort of hitch on them.

Didn't M-B offer a similar flat-bar hitch? But the one I used appears after-market (Curt). Of course, M-B designers were not infallible, as us bottom-feeders trying to keep these old W123 cars going must design work-arounds. A few other production cars used aluminum bumpers. One was the ~1976 Plymouth "Feather Duster" which also had an aluminum hood, shooting for low-weight, high-mileage. The new Ford aluminum trucks (even the bed) stimulated interesting "alum vs steel" ads from GM.

charmalu · #6 09-21-2016, 11:16 AM

I have seen some pictures in the past where the bumpers came loose from the Shock Absorber thingies that attach to the car body.

I would not trust the hitch to be bolted to the bumper.

Did some searching to find pictures I remembered from past threads,

I needed a hitch for my 300SD so I used a curt 11805

towing a trailer

http://www.peachparts.com/shopforum/diesel-discussion/305920-w123-receiver-hitch-$172-week.html

Trailer hitch receiver for 126 body

W126 Trailer hitch

charmalu · #7 09-21-2016, 11:32 AM

Here is one I totally forgot about, I saw at a PNP several years ago.

Mercedes and trailer. Now how much can these turbo W123 pull?

Rogviler · #8 09-21-2016, 12:09 PM

Interesting... Did the sedans ever come with them stock?

Aside from the pulling issues, I'd also worry that a minor rear-end hit would be bypassing the shocks and going right into the body. Wonder why they would design something to attach that way.

My wagon came with the Curt 11805 or very similar and it's as tough as I think you could make it.

-Rog

dude99 · #9 09-21-2016, 01:43 PM

Nice job, but as mentioned the bumper mount ones aren't the best. The stock ones bolt on to the bumper mounting bolts and the the bumper bolts on overtop.

t walgamuth · #10 09-21-2016, 01:45 PM

Factory hitches might use the bolts that hold the bumper shocks on but they bolt between the unibody and the shock flange.

The aluminum bumpers corrode at the attachment points first then when bumped break loose, sag down in front then fall off.

If you live where its dry it would be a lot better.

Rooster300SD · #11 09-21-2016, 02:44 PM

I saw that hitch Bill got. It was in the PNP at Rancho Cordova.
That was a home made setup, just drilled through into trunk and
I didn't think it looked too safe.

The one I pulled from a W126 was factory and made by Oris.
There's photos and an installation drawing in Post #6 of my thread
Oris trailer hitch

I'm still looking for the arm & ball if anyone has one for sale.

Jeff

BillGrissom · #12 09-21-2016, 11:43 PM

Thanks for all the useful info, and inspired me to search more. Post 11 is incorrect about the PickNPull hitch I started with being "home-made". It is a Curt 11614, an "engineered design" for the W123, and avail for $159 at Home Depot or $139 on ebay (free shipping both). It appears I was wrong that a load had bent the bar down, since the photo looks like it is made that way. BTW, don't assume powder-coating is the bee's knees. This hitch had rust under the power-coat everywhere, but was just surface so I was able to wire-brush it to clean steel.

The Curt 11805 is much better since attaches to the frame instead of the bumper, but $220, much heavier, and appears only for the wagon (gas or diesel).

The factory hitch appears to have been dropped by 1982. It wasn't a flat-bar, rather having an integral ball, which isn't very flexible (last photo).

I agree the bumper shock mounts are not very strong, having a fairly thin aluminum case. The way I broke the front one on my 1985 was that I rigged a tow-bar to the frame, passing under the front bumper. When I drove up the driveway, the tow-bar pushed up on the bumper, which cracked the mount. At least I got the car home after the engine failed at work (crankshaft jammed by chipped pistons). Don't let fat guys jump on your bumpers or you might hear a snap.

yuke · #13 09-22-2016, 07:13 AM

I have the hitch that is in your left picture on my sd and it is holding up fine. I had a factory made I think it was curtis bolted to the frame on a 95 grand voyager and after probably 20 yrs. on the vehicle at the end of a 700 mile trip the thing was barely hanging on almost dragging the ground I never felt so lucky that it did not break away. Took it off to a professional welder he reinforced and rebuilt it still on today yet. Moral to the story is even a factory built hitch bolted to frame can rust away and fall off you should use common sense as how they are built and attached and inspect them periodically I never thought to inspect mine because it was factory made from heavy metal bolted to the frame but rust took it down.

Will300D · #14 02-24-2017, 08:00 PM

Reviving this thread:

Has anyone successfully put on the Curt 300TD hitch (#11805) onto a 300D (sedan) with minor modifications?

Would be great to hear if it's feasible before I move ahead wit the purchase of the hitch.

Thanks in advance for the advice,
Will

ROLLGUY · #15 02-26-2017, 08:00 PM

Quote:

Originally Posted by Will300D

Reviving this thread:

Has anyone successfully put on the Curt 300TD hitch (#11805) onto a 300D (sedan) with minor modifications?

Would be great to hear if it's feasible before I move ahead wit the purchase of the hitch.

Thanks in advance for the advice,
Will

I haven't, but can't imagine that it would not work. I believe you can't go the other way (sedan hitch on a wagon). I just ordered a hitch for my W211 ('05 CDI), and I am going to see if it will fit on a 123 without too much modification. If it is not to much trouble to make it work on a 123, I will start a new thread with photos. It comes with a 2" Euro ball (I think that is cool)

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