Worth replacing a 123 steering coupling?
 

Worth replacing a 123 steering coupling?

I have tightened up a lot of my 300TDs steering with upper control arms, tie rods, idler arm repair, etc. The only remaining problems is a manageable wander at highway speeds, about +/- 1.5" of play and the fact that I have to hold the wheel at 15 degrees to the right to go in a straight line .

I noticed that the steering coupling has a hairline crack all the way through from one edge to the center on one side and another crack just starting on the adjacent side of the coupling. The rubber is very hard, but not dissolving, and appears intact.

Does anyone think that I will gain $60 (partshop price with shipping) worth of benefit from replacing it?

Overall, it seems like my steering is pretty good, though not the same as the first day it was driven. I am not super enthusiastic about adjusting the steering box at this point.

thanks

The cockeyed steering wheel is probably because when the front wheels were aligned the tech didn't set the steering wheel straight. Someone familiar with MBZ alignments should be able to realign the front end with the wheel set straight. The steering box is an easy fix if you still have play after eliminating most other causes. There are several threads on the topic, just do it 1/8 to 1/4 turn at a time and DON'T over tighten. As to the coupling, I doubt that is the source of your play but if it is not in good shape you probably ought to replace it.

Just a little FYI, some "slop" is within MB specs. Per the MB service manual for the W116 cars at least, up to 25mm is normal. This would be about 1 inch turning the wheel from left to right. Being it that there are very few raods that are perfectly level, your steering wheel will be tilting one way or the other. If you are used to rack in pinion steering, the old style "recirculating ball" type steering on Mercedes, will seem loose.

"Worth replacing a 123 steering coupling?"

Do you mean the steering coupler that breaks at high speed and can kill you one?

WOW!
 

Wow, I too have the same problem of having to hold the wheel 15 degrees right to go straight. My wheels were aligned, 3 times and have had the box adjusted a number of times. Guess what? I need a new steering box. Looks like we're all in the same boat.

Just out of curiousity, has anyone changed one of these steering couplers? How difficult is it. When I visited my folfs last, I noticed some cracks on my father's (W123) steering coupler.

One thing of interest may be that most alignment shops don't know that you need a spreader bar and a rear ride height guage to do a proper alignment. The spreader bar is placed between the front tires and pushes them apart to "load" the front steering.

Just a little FYI, I tried aligning the front end myself at our shop without one and it is about 15 degrees off to the left!

strange coincidence
 

Wow, that is weird, both my 123 and 126 are off 15 degrees to the left...

I think I have four ball joints to do, then it will be off to the alignment shop.

Let me know if it sounds strange to ask/require that they use a
1- spreader bar on the front and
2- a ride height gauge on the rear

Could the PO have had the last alignment done without #2? Currently, the tops of the rear tires lean in, especially under load. I replaced the shocks, and it smoothed the ride, but the tires still lean and I am doubt that it is the springs. Can an alignment address this???

Well, your rear tires are tilting in most likely due to soft rear springs. During normal operation the rear wheels tilt in and out as the rear suspensioin travels up and down. The wheels move in an arc, so to speak. When the rear springs start to sag, the rear wheels are forced upward causing to tops of the rear wheels to tilt in. This occurance is normal, but due to tired springs. My 300D is getting new springs, when rear springs are replaced the rear alignment will return probably close to the original settings. The same applies to the front, just not as drastic as the rears. a quick and painless way to check to see if the rear springs are indeed tired, run your car low on fuel, take a tape measure and measure the center of the rear wheel opening from the highest point to the ground, and measure again when you are done. There is no set spec, but my car drops about an inch and a half, due to the springs not being able to handle much weight anymore.

I would ask if they have those two items, the only place you may find them are at a MB dealer that has an alignment machine, or a very high end tire shop. There isn't anyplace around here where I am that has one, I eyeballed my front toe adjust when I did mine on our machine at work.

Call around!

perfect thanks
 

Darn, I was hoping the springs weren't the cause. I will check like you say. Thanks for all the other advice also.