Just talked to Chris @ C&M Hydraulic. Good info here! - PeachParts Mercedes-Benz Forum

tinypanzer · #1 04-06-2009, 08:18 PM

I spent close to half an hour talking to Chris at C&M Hydraulic today. Wow, what an informative and interesting conversation. I asked him about steering gear wear on 126 Chassis vehicles and he shared a wealth of information with me.

The first thing is the common misconceptions about the adjustment procedure on the steering box. He said that people commonly mistake the height of the adjustment screw as being an indication of either wear or previous adjustment attempts. Not true according to Chris. He says that the adjustment is there merely to compensate for casting differences in the parts, and that each steering gear is unique. Indeed it is possible for a brand new gear to have the adjustment screw further out than an old one that's been tweaked. So, no more using the screw height as a go/no-go indicator for a good gear at the boneyard.

He also had two other things to say about that topic. The first was that he has never seen an adjustment of that screw fix much of anything. The other thing he said is that while Mercedes doesn't say that re-alignment after adjustment is necessary, he feels otherwise. When you raise that adjustment screw, you are pulling the pitman arm further inside the body of the box, which will change your toe. Sigh. He also said that re-alignment is necessary if you replace the box for the same reason.

Now, about the box itself. I asked him "what is it that actually wears out inside those boxes, the balls?" He said that pretty much the only thing that doesn't wear out are the balls, which ironically, are the only parts for these available as new. One thing he said is somewhat common are busted springs inside the actuator valve. This will manifest itself as loss of power assists at slow or no speed, either in one direction or both. His company actually had custom springs made for the gears he remans, and all 126 boxes get these new springs regardless of the state of the old ones. He said that the input shaft can wear out, as can the bearing at the top of the box. The pitman shaft can also wear out. Since no new parts are available, all remanned boxes by any company will consist of parts picked from various units and measured for being in spec.

So, I followed up by describing my road wandering problem, which I had assumed to be related to all the slop in my gearbox. He seemed to think that perhaps a portion of what I was describing was gearbox related but was careful to point out that I should do the guide rod mounts and any other suspicious steering component at the same time, so I could get all the benefits of new parts with only one trip to the alignment shop. Good advice.

So then I asked him "Is there anything I need to replace at the same time as the steering gear?" He said not really, but pointed out that in a few instances, old gear boxes develop internal leaks that cause the hydraulic pressure to drop below normal. When you put in a new box with tight seals, the old pump can sometimes go south because its tired seals cannot handle the normal high pressure which has suddenly been restored. He said it wasn't that common, and it was only after he started remanning so many units that he ever heard of the issue.

Here's the cool thing - After the rather lengthy conversation, for which I thanked him profusely, he said something very interesting. He said "I wish more people would call like you did beforehand so they will know what to expect and what not to expect" (I'm paraphrasing a bit).

All said, I was very comforted by his level of knowledge on the subject and when I finally bite the bullet and buy another steering gear, it will be from his company.

Chris, if I got any of this stuff wrong, sorry man! Feel free to correct me.