has anyone used a threadlocking product on the upside down bolt? just to be safe?

Could drill a hole and use a cotter pin to feel really secure.

securing the nut
 

The original nut coming with the Mercedes repair kit (bushings and washers, bolt, nut) is self-locking (squeezed nut).
Forgive me my wrong words and / or spelling :-)

bis denn,
Christian

1989 300TE

Proper instalation
 

If at all possible I would install the bolt and nut as intended by the manufacturer. These things are set up that way for a reason. I agree with CSNOW, if you must install upside down I would probably drill hole and use wire tie or cotter pin to ensure the nut won't back off and bolt fall down.

I found little if any clearance with bushings in, but after prying off bottom bushing and pushing up top bushing I had plenty of wigle room to get bolt out and new in.

Good luck,
Joel

........if you are caught the secretary with disavow your actions......
 

This is turning into a long thread.... Knowing the importance of the steering components and keeping them together, I understand the reluctance of some not wanting to turn the idler arm bolt upsidedown. Like I said previously, I researched again and again and had many different ways suggested. Two of the three most popular would not work for me, so I opted to turn mine upsidedown. I didn't mean to say that was the only fix to this problem but after reading from several senior members and I believe even a few techs with many years of experience with this repair I felt comfortable doing it this way. Even though I've never had any locknut back off of a bolt, I have checked several times to ensure that everything was/is still OK and I can say that after 2500 miles of driving winding hilly roads, freeway driving, and with me living 3 miles down a dirt road that is travelled at least twice a day, no problems have cropped up with the repair. This fix that worked for me may or may not work for you (the bushing out approach did not work for me due to very tight clearances with the exhaust). Perhaps doing a search on idler arms you will see the info that I read.

This is/was not meant to step on any toes here but I do tend to get long winded sometimes when having to explain my particular point of view. Happy Motoring

Man, have I screwed some bolts.

I personally don't see a bunch of difference in bottom or top as to whether it might back off. With the bolt on the top what keeps the nut from using gravity to work its way out. I don't think gravity has anything to do with it.

I do think the engineering difference if there is any is that having the nut away from the possibly flexing part is the more secure way In this case I doubt that the idler arm really flexes on the bolts if its all properly tight.

Read
 

As you can imagine I read everything and anything I could on this repair prior to performing it.

One quick follow-up question. With the nut on top, how would that affect one's ability to properly torque the nut?

I am confident you probably won't have any problems either way it's performed. Furthermore, you would feel sloppy stearing or vibrations long before the nut would work it's way completely off.

Joel

I had the same concern, which contributed to my decision to install it right-side-up.
There is no way to get torque wrench on the top.

It seems like the torque value might really matter on this one.
Perhaps not. I have an open mind on the matter.

Torque spec of the bolt to the nut or visa/vs shoud not make any difference .
The drag /friction on the bolt shaft is nil from the bearing surfaces..
Look around and see how many bolt heads are facing down in any piece of machinery... gravity is not the factor of bolt lossening.
I would think the original position of the idler bolt is for manufacturing sequence ease only.....

Car: 1989 260E

I need to replace my Idler Arm bushings. From this thread, I gather I must:

1. Remove nut, push bolt up and pry lower bushing out.

2. Pry top bushing down(?) and out from around bolt.

3. Remove the bolt by angling through idler arm hole and sliding up and out.

4. Reassemble in reverse -- angle bolt in from top, align bolt, slide in upper bushing, slide in lower bushing, attach nut and tighten as hard as possible.

I still have a couple of questions, one or two of which may be stupid:

Q: Do both front wheels have to be off the ground, or can I just jack up the right side of the car?

Q: Do I need to be underneath the car, or can I get at the idler arm after removing the right-side wheel?

Q: If I install the bolt upside down, as is suggested in the thread, do I also reverse the order of the washer and what appears to be a type of cap that comes with the kit? (See photo.)

Q: How tight do I need to tighten the bolt?

Top bushing would be going upwards in this case. As you probably noticed in the thread, I had no luck with this removal technique. Hopefully it will work for you.

Use the proper torque value. I forget what it is.

I strongly suggest supporting the entire front end properly with jack stands. Much safer, and better access. Indeed, you may want to lift the engine slightly with the jack for better clearance, so having it on stands helps there, though this was still not enough clearance for me.

You will want to be able to get under the car.

The cap is designed to keep water and debris out of the bushing tube. I would put it on top. I believe there is also a spacer washer that is not shown. I'm not sure where it should go in an upside-down scenario. I believe Larry Bible asked this exact question in another thread, and got an answer. See if you can find it.

I forget the torque value. I believe I already stated my concern about getting the proper torque value for an upside-down mounting. Torque values always apply to the nut in a nut & bolt scenario. There must be a reason for this convention. My theoretical guess is that slightly more torque would be required on the bolt end to be equivalent. Why? There would be some additional friction on the bolt shank as it turns within the bushing. Put another way, how much torque is required to spin the bolt before the nut is even applied to the equation? This higher 'baseline' value would need to be added to the total torque. That's my theory to explain the convention.
I have not tested this theory or done any research. Close enough? Probably, but I really do not know. Enough on that. Arthur is probably right. I'm sure if it's just a couple of Ft-lbs either way, it's no big deal anyways.

Best of luck, and happy wrenching!

Idler arm bolt
 

Hi there,

Well as you can see, I was the starter of this here thread and my installation went without a hitch.

I did the following:

Jacked car up and rested on jack stands (whole front end), could get away with just passenger's side though.

loosed and removed nut.

Popped out lower bushing.

Pried out top bushing with bolt still passing through it, not a hard thing to do.

With top bushing now sitting on top of where it had been pushed into I was able to angle bolt and push out easily past the exhaust. Top bushing and all.

Assembled in reverse order.

Even if you were not able to pry the top bushing out prior to dissassembly and had to cut the bolt, I would think you could reasemble using this technique.

good luck,
Joel

Great news!
I have got to wonder if the 'newer' models have a slightly different exhaust design that makes this repair somewhat easier to perform. I have spent much 'quality time' with '86-'88 models, and there is simply no way this procedure can be done in that manner.

THanks everyone for your good feedback. I'll be getting the bushing kit this week, and it looks like it will not be too hard a task.

Csnow's comments, however, have me worried; will my '89 260E be one of those difficult designs to work with?

Sorry man.
I see some frustration in your future...