cool_breeze

My 2002 E320 has a torn boot on the passenger side Upper Control Arm ball joint and is very squeaky while driving. A complete UCA is about $100 online, so that's the path I'll probably go.

Questions:

Torque specs for this job?
Is possible to replace just the bad ball joint?

There is only a little information available for an UCA replacement, so any tips or pictures would be greatly appreciated.

Thanks!

Hirnbeiss

See this thread

cool_breeze

Thanks, that thread will be my main source of info when doing the job this weekend.

Looking for torque info for the nuts. Anyone? Thanks!

RichardM98

The torque for the self locking nut on the follower joint of the upper wishbone is 45Nm (except 210.08/28).
The nut on the long bolt connecting the upper wishbone to the frame is 65Nm (except 210.08/28).

The nuts should be replaced during service.

BTW, there is a special tool (MB) for 'pressing' the joint out of the wishbone after removing the nut.

cool_breeze

Thanks for the specs. According to the VIN decoder, my chassis is 2100651B450873, so it looks like the exceptions don't apply and I'll go with these specs.

I'll order the new nuts, too.

Thanks!

RichardM98

I wasn't sure last night but the 08 and 28 are the 4Matic models which obviously have a different front axle.

cool_breeze

Did the job today and it was smooth sailing until near the end, when attaching the upper ball joint nut to the vertical arm.

I ordered a Lemfoerder UCA, Part No. 2103308807, from Autohausaz. The supplied ball joint nut is 16mm, while the original MB one I took out was 18mm. Weird, but the inside threads are the same, so no worries, right?

At first, the 16mm nut would only thread a bit, stop, then just spin with the ball joint when I turned the wrench--very frustrating. Then, I was able to thread the nut more, it kept tightening, resulting in the crushing of the ball joint rubber boot--not good (I think). Seems like the old ball joint had a stopper of some sort to prevent the crushing.

Is it ok to just keep tightening the nut, knowing that the result is a crushed ball joint boot, and stopping at 45Nm?

I've attached 2 pictures, one of the new right side (showing the gap on the threads since I backed off) and the driver's side original for comparison.

Any suggestions? Might I need the OEM dealer part rather than Lemfoerder?

RichardM98

I checked the WIS procedure and nothing special -- just install in reverse order. Were you able to compare the old and new part visually?

I have not performed this repair myself but I'm sure others have. As I understand it, the seat for the follower joint (ball joint) is tapered. On connections like that (quill/chuck on a drill press for example) the secret is to get both surfaces as clean and grease free as possible. There may be a film of protectant on the seat of the new part which prevents friction from helping.

Occasionally, parts get updated so cosmetic differences aren't uncommon. It's always possible that you got a very similar but not correct part. Usually, the test is comparing with the one you took out for all the critical distances, threading, etc. Lemfoerder does put MB part numbers on some of it's OEM stuff so look for that.

Since the joint is capable of moving in a pretty wide arc I wouldn't be too concerned if there's a little wrinkle in the boot. It will probably disappear when the car is sitting on the ground.

You might also try posting over on benzworld again. More DIYers per capita over there.

Hope this helps some.

cool_breeze

Ok, posted again over at B-world, thanks for suggesting that and thanks for your help, too.

I compared old and new visually and they looked the same. The old parts ball joint boot was ripped and beat up pretty good, so an exact match was difficult. As far as thread distance, they look the same, but the new nut is threading so much higher up the threads than the old nut did on the old part.

I'll take the wheel off again and look for a part number on the part itself.

These pictures were taken after the car was on the ground and a short test drive, so the wrinkle/crushed boot remains.

If I can't figure anything else out, I think I might just tighten it back up to 45Nm, regardless of how high up the threads the nut goes and regardless of how crushed the rubber boot of the ball joint gets, but I think I'll always worry that I did it wrong.

RichardM98

Nuts come in different sizes even with the same threads. A larger nut (18mm wrench) would also be thicker so fewer threads would be exposed.

I don't know if you want to fuss with it but with the nut loose see if you can turn the shaft a little to take the twist out of the rubber boot. If you can, then start with the shaft twisted a little in the opposite direction so when it's tightened there's no wrinkle. Hope you can understand what I mean.

cool_breeze

Well, finished the job to my satisfaction and would like to thank you folks, especially RichardM98, for your advice. Also, Michakaveli's notes on the supplied link were great, too, so please use them.

Recap/Tips/Advice/2-Cents:

If I had to do it again, I'd get the original Mercedes part, probably cheapest from Parts.com since they use an Illinois Mercedes dealer. The Lemfoerder part has too many differences than the original, the biggest being a much cheaper rubber boot, with a wimpy metal o-ring for security. Also, the threads on the ball joint are about 1/8" longer than original and the ball joint nut is 16mm instead of the 17mm present on the original (not the 18mm that I mis-spoke about above...). These little differences threw me way off and easily tripled my time spent. If the part had been an exact match, this would have been a maybe 2 hour job, pretty easy and straight forward.

You need a seriously offset 16mm box-end wrench to attach to the nut that is inside the rubber body plug inside the wheel well. This trap door could be better placed and angled, but it is what it is. Without an offset wrench, you'll never properly attach to the nut.

The wrench I ended up using was the boxed end of the Spark Plug Boot Removal Tool I purchased from Ohlord. It was a perfect offset and fit. I lightly taped the new nut to it for reattaching to the bolt. Worked like a charm.

I've attached a few pictures of the installed Lemfoerder part and one of the failed original part. The original part has a much better, stronger, flatter, rubber stopper that helps seat the ball joint in the vertical arm.

RichardM98

Glad to see you got it done!

Hirnbeiss

Any improvement in ride quality?

michakaveli

mine rides pretty well.

cool_breeze

Big difference. Nice and quiet, very smooth over bumps. Mine was pretty much metal on metal, though.

Overheated

Hi everyone. It's been awhile since this thread concluded so I hope there are still ears out there.

Stuck in Mexico trying to secure the suspension self locking nut for the follower. The bottom nuts are readily available, but the follower nut ain't.

A202 990 08 51 Lower Ball Joint/Tie Rod End Nuts

N910118 010000 Upper Follower Nut

Is it the same as the lower nuts even though they're different OEM numbers?

I believe the spec on the lower threads is 14x1.5mm. I believe they're different part numbers for a reason, but is this the same for the top nut?

Someone want to be my new best friend?

khomer2

Answered

Overheated

Answered where? I must have missed it?

khomer2

Did you click on the link?...
You do realize you also posted on the other forum, right?

And got your answer.....

Overheated

Thanks. Helps to be concise.