Door check strap, aka check rod W123
 

My right rear check strap went south in a big way all of a sudden. It was objecting to being closed or opened from first position.

I closed it once and thought I better not do that again, it took a lot of force, and I once ruined a BMW door because of a bad check strap. It came partially loose and bent the mounting point back-and-forth a few times too often.

The next day I forgot and opened it, it slides to first position plenty easy, but then doesn't want to go anywhere. I took it apart on the spot, it was of course very dry, absent grease.

I greased it up, worked it back-and-forth in a vise, it seemed to be OK, but not ideal. I left the door panel off to see how it came out. It's not good, making noise already again, needs replacing. One front door starting to be noisy as well.

The difficulty, all of the part descriptions refer to front doors only, I have a hard time believing they would need to have two different items, one for the front one for the back.

I did find one site, a competitor of Pelican, who say that it fits front and back.

Anybody know? I replaced all of them on my SDL when I bought it, but I had access to decent later model gasser 126 models still at boneyards back in 2017.

This is my first W123 check strap experience. I doubt I'll find anything good at a boneyard.

W123 Door Checks
 

It's been well over 10 years since I hassled this, IIRC they're left and right but not different front / rear .

Perhaps I simply use whatever M-B was able to supply but all the eight doors on my two W123's open and close easily .

If you're buying parts I HIGHLY recommend buying four new strikers RIGHT NOW before they go obsolete too .

I have pulled a few of these from the boneyard. When they are that cheap and seem to work fine, I save them. Two bolts on the front of the door, one behind the door card, and the pin with clip. Super easy. Also get some grease in the door hinges.

my advise is if you haven't already, grease the things especially the doors that don't get opened often.
I learned this the hard way. I had an '83 300D that I bought from the original owner, a man who really took care of the car. It didn't need anything much, new injector return lines and I started driving it. I had to pick a couple friends at the airport so off I went and pulled up at the busy curb and helped load some luggage in the trunk.
The gal that was going to ride in the back seat drivers side couldn't seem to close the door. The mechanism was frozen up and the arm would absolutely not go in!
As I was out trying to accept this a traffic cop walked up and said I had to move along. I explained the problem and the cop watched without saying anything more. With great embarrassment I told the passenger to hold the door closed with her arm while we drove home, some 10 miles, not far but every inch I was watching in my rear view mirror to see if a vehicle was going to pass and I moved over a tad.
Thats when I learned how crappy the 123 door mechanisms are! That and the damn latches where a piece of plastic breaks off then the latch quits. I just replaced a couple of them on my old wagon. what a ***** of a job and the hex bolts that get rounded off. I've learned how to manhandle those P.O.S.

W123 Door Hinge Lubrication
 

I'm glad to learn I was not alone in this ! .

I've had a couple jamb when I was away from home, sometimes levering the door open & shut *just* at the binding point would get it closed and then I'd leave it closed until I could take the door card off and replace the darn thing .

I disagree, they're not poorly designed as they work well and as a Mechanic I've seen far too many vehicles with failed door checks .

These usually give plenty of warning before failing and jamming the door open .

The original types from the early w123 were modified by later types. Both will fit any w123.

Bone yards are good sources.
They can be rebuilt by parts from failed units.

I keep spares in storage.

Yes grease them up.

If I recall correctly the difference between the front and rear check is how far they allow the door to open but they can be interchanged.