I need to replace the guide rods on my 81-300SD as I can hear them over rough road, etc.. I HAVE READ all of the threads that I can find and the DIY articles relating to this problem on this site. I am a little anxious about doing it, but I cannot afford to have someone else do it.

So, do I need to replace them immediately, or do I have some leeway for attempting the job. In other words, will I damage the car or place my wife in danger for local driving over the next month, if I do not replace them this weekend?

Thanks,

Don

__________________
84-300D 256K
81-300SD 217K (Wife's)
79-300CD 212K - Project
89-Volvo 245 305K

Unless they are ready to fall out, you don't have to replace them right this minute. I would be careful driving at speed if you get serious shaking in the front end. Sometimes as they go bad, they can allow some pretty bad vibration/shaking. You can be the judge of this. If they are just making a klunk from time to time, you have time on the replacement. As they go bad, the front end alingment gets worse so tire wear can be an issue with putting off the job.
Be advised, this job can take some time to do so be sure you have a spare car available while you do the work. Nothing worse than doing a job badly because you had to rush. Just did them on my '86 126 and it's nice to not hear the klunk anymore. I had a bit of an advantage. I had an old set of carriers/mounts whatever you want to call them. This way I was able to remove the old joints and bushings before I took the car apart. Oh, and buy the real thing from the dealer on this job. I have seen aftermarket parts that were not as strong/well made as factory.

BobK,

Thanks for the insight. I run only older used cars (Mercedes and Volvo)...spare vehicles are a must! I have a week off starting on Thursday, so I might start it then. So, you are saying that the parts from the online sites are not as good as the dealer parts in this case?

Don

__________________
84-300D 256K
81-300SD 217K (Wife's)
79-300CD 212K - Project
89-Volvo 245 305K

My experience was that the aluminum core in the sub frame (I guess that's what they are called on these cars) bushings was not as strong in the aftermarket parts as in the factory parts. BTW, I think you can get the bushings out of the sub frame pieces with a good sized gear puller and some big washers. I use light sandpaper and scotch-brite pads to clean the bores where the bushings go. And a little silicone spray makes thigs go together easier. The guide rod joints can be a real pain to remove from or install into the mounts. I wound up using a sanding drum in a Dremel tool to clean out the bores after I pulled the joints. Still working on a design for a tool to make it easier to install the new joints.

Local driving she should be ok, mine have gotten so bad that the front end shakes violently at 55 +. You have probably seen the thread I started on this problem-which is the intense shaking. Check out thread if you haven't. It also does the clunk when braking and over bumps at slow speed. It is looking to me like these guide rod mounts are causing it( the shaking). The boots are completely gone also, both sides.

I would not let the vehicle be driven on freeway or highway or over 45 mph. Scared the you know what out of me first time it happend.


INFO:

The prime purpose of this joint is to take the longitudinal loading of the front suspension. They can get so bad that the front wheels can be felt moving forward and backward during braking. It’s rather unusual to get that bad because, before that, a clunking sound is usually the complaint with actual diagnosis often quite difficult. Once familiar with the symptom, one can condemn the joint when the boot is broken and the clunk is evident.

Another common complaint due to this mount/ball joint is brake pulsations and/or shimmy at a resonant speed around 60 mph.


Found this here
http://web.archive.org/web/20050307000824/www.continentalimports.com/ser_ic4232.html

__________________
1982 MBZ 300SD Turbo Diesel- just turned 200,000- just breaking her in

Dazsa, I too have an 81 300sd with really worn guide rod mounts that I replaced a few weeks ago. A few bits of advice......the bolts that hold the guide rod mounts to the body can get rusty.A few days before attempting this fix spray PB Blaster on the threads. Do this multiple times over the period of a few days. The nut that the bolt threads into is the worst designed Mercedes part I've ever seen. It can be a real bear......use a good high powered air gun to get the bolt loose. If the nut breaks free of it's keeper, you have to wedge something in there to keep it from spinning while loosening the bolt. Also, getting the old guide rod mount out can be a pain if you don't have a press. Just keep wailing on it with a hammer. Make sure you get the housing VERY clean before re-assembly. Also, the new part will be very stiff. Work it round and round while it's off the car as many times as it takes to loosen it up a bit. This will help out greatly when you are putting everything back together!!! Good luck, this is a PITA!!!!