Here's a good question that might help everyone:

Although in the best of all worlds we would all replace all of our rubber on the car, what would be a good and SAFE (read: non-deteriorative) lubricant to use on our rubber suspension/steering bushings?

Any advice would be well-appreciated. Thanks.

Silicone based lubricants only. Silicone grease is the way to go. Use silicone spray where you cannot effectively introduce grease. Do not use anything with a petroleum product in it – that is what will deteriorate rubber.

RTH

NAPA sells a silicone spray call Syl-glide or something like that.

Sixto
91 300SE
81 300SD

Hey, Sixto:

A question. I was just inspecting my steering linkages, and I noticed that the rubber on my draglink is torn on top. Would this cause some harsh feel through the wheel? And if so, Can I replace this easily?

If not, can I coat it with something?

Rubber on your drag link? The only rubber I can think of is on the ball joints that connects to the pitman arm and idler arm. I think worn ball joints will cause loose steering rather than dragging steering. Have you checked your PS fluid level? The ball joints are integral with the drag link rod. They are threaded but don't/won't come off.

Sixto
91 300SE
81 300SD

Sorry, Sixto. The rubber is on the ball joint end of the arm attached to the damper. (Idler?). The joints look firm; I can move them. But when I move them entirely down, I can get a clunk noise from - I think - metal hitting metal. That's when I checked the rubber bushing, which is torn. Other than that, the parts look fresh - and I do NOT have loose steering. Just some feedbaack in the steering wheel that I'm trying to isolate. Perhaps this is it. Any simple ideas?

Robert, I still don't have a good picture of what you describe. The idler arm is not attached to the steering damper. The fixed end of the steering damper attaches to a point close to the pivoting end of the idler arm, but both are attached to the chassis, not each other. The idler arm has no ball joints per se. Attached to the idler arm at the free end are a ball joint from the right tie rod and the a ball joint from the drag link.

You talk about a busing so I don't think you mean the rubber covering a ball joint. The bushings I think of in that area are the idler arm bushings. They support the big bolt that goes through the idler arm and the cylinder below it. Those bushings can be worn enough to cause steering problems without being able to jiggle the idler arm by hand. Easy to replace on an SD, the exhaust has to come off a 300SE/L unless you do the unadviseable and install the bolt from below. I don't know what it takes on a V8.

But maybe the idler arm bushings are a tangent. Is there a picture you can attach for reference? If you have the CD manual, you can copy a picture by pressing Print Screen then pasting the result in MS Paint. I'm not a lawyer and I don't advocate copyright infringement, blah, blah, blah.

Sixto
91 300SE
81 300SD

The problem with petroleum based lubricants is that they deteriorate the rubber. The problem with silicone based lubricants is that they repel water and are persistant.

Mercedes recommends a water based lubricant. I assume this is the case so that it will dispel after assembly and no longer shift as easily once on the road.

There are only a few lubricants that do that.

Kentucky Jelly?

__________________
It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D

Walgreens was having a good deal on water-based lube last I saw. Good thing you're considerate with her.

__________________
Only diesels in this driveway.
2005 E320 CDI 243k Black/Black
2008 Chevy 3500HD Duramax 340k
2004 Chevy 2500HD Duramax 220k

Dish washing soap.

Sixto
MB-less

There's really nothing to lubricate. The way suspension link bushings work is the outer steel sleeve is an interference fit in the suspension member, and the inner steel sleeve is held firm by the through bolt.

All movement is within the rubber itself - like bending an erasure. There are no sliding surfaces.

These bushings often show cracking around the edges you can see, but that doesn't mean the bushing is bad. The best way to check is to use a prybar to see if there is excessive movement/lack of resistance in any direction. That could mean the interior of the bushing - the rubber - is deteriorated.

The steering linkage has mostly solid ball joints. One exception on some models may be the idler arm connection to the frame. The rubber boots you can see on the steering linkage joints are there to contain the grease and keep dirt out... same with the steering knuckle ball joint boots.

Wear in the steering linkage joints can cause a "cracking" or "snapping" noise as you turn the wheel, especially if there is also vertical suspension movement. This is the current situation on my 83K mile 190E 2.6. There is one worn joint on each of the tie rods and center link, so I have to replace all three. I have Lemforder replacements from Pelican, but I have to check that I have a proper size tie rod puller. With a proper puller it should be a fairly easy job.

The ball joints are okay, but the boots are torn, so I also bought new ball joint boots. I don't think that job will be too hard, either. With jack stands under the front control arms the knuckle/strut can be easily separated from the ball joint stud by removing the pinch bolt and jacking up the knuckly/strut up via the brake rotor enough to lift the knuckle clear of the ball joint stud. The tricky part will probably be getting the lower snap ring onto the boot.

Duke