Ball Joint and Idler Arm Replacement
 

My 300D has been making a clunking sound from the front end for a while. Being both somewhat busy and very lazy, I haven't done the troubleshooting on this myself, except to get under the car and inspect the control arm bushings, which seem to be intact, but a bit weathered.

Lately, I noticed that the right front tire is getting feathered on the inside of the tread. I also recently bought a much-lower-mileage 240D and realized that the front end of the 300 feels much sloppier than the 240. I was used to American land yachts and the 300 felt more or less normal in comparison to them.

So, I brought the 300 to my local independent shop, with whom I've been doing business for over a year, and who've treated me fairly in the past. The diagnosis: Bad upper and lower ball joints, and a bad idler arm. Ok, pretty much what I expected. Now the kicker-they want $1600 for the repair. This seems excessive.

I looked up the ball joint replacement procedure in my Chilton manual, and it looks pretty straightforward, though it does require some tools that I don't have, such as a spring compressor and a ball joint press. As I mentioned, I'm pretty lazy, so I'd like to farm this work out if the price is good. OTOH, I'm also cheap, and this is a car I bought for $800, so I'm open to the possibility of buying/renting the tools and doing it myself.

Fellow forum members, what do you recommend?

Note: I don't have a garage, and my aparment management frowns on vehicle repair in the parking lot, but I may be able to work a facility rental from a co-worker who just had a shop built.

You don't need a spring compressor to replace the ball joints. But having the Mercedes press will save a ton of aggravation.

well
 

well I looked up the parts and they are less than 100 bucks...
here from phil....much less.... autozone rents parts... there is this thing
that looks like a crowbar....just picture the back of a hammer...
and its slanted... you just drive that under the ball joint and it will pop out..

its not too bad.....I think 1600 says DIY:cool:

In my search, I read the W124 DIY page for ball joints and noticed the part about the Harbor Freight press not being right for the job. If I end up buying one, what should I look for (dimensions, etc)?

I saw in the DIY how the guy didn't use a spring compressor, but I think I'd rather use one, as his method seemed a bit dangerous. He mentioned that a W124 front spring is still under 4 inches of compression at full droop, and that's a lot of energy. Are the W123 springs configured the same way?

Blueranger, it sounds like you're talking about what I usually call a pickle fork. I can/have used them in the past. Now for getting the new ball joints in, I still need a press of some type-right? Will an Auto-Zone rental do it, or do they not work with the MBZ parts?

ok first off, when does it make the sound? stopping? starting? turning? on your car the idler arm is not a wear item. the bushings are but not the arm. the bushings being worn will cause slop in the system. lower ball joints are a very common wear item at high miles. again those will cause slop but usually not a pop. it sounds more like a squeek. take a look at your guide rod mounts, they will cause a "pop" when worn out. you dont need a spring compressor for lowers or uppers. as blueranger said you can rent a tool from autozone called a pickle fork. it will do fine for the uppers, but if you plan to do the lowers it wont help.
the upper ball joints are not replaceable. you will need a new upper control arm.

It makes the sound when I pull out of a parking space in reverse, then change to drive and turn hard to the left, and when I pull forward-POP! It usually sounds like it's coming from the front, but sometimes it sounds like it's from the rear.

Guide rod? I'm unsure of the nomenclature. Is that the part that runs back to the rear of the front fenderwell? I was trained on "regular" SLA and live axle/leaf spring suspensions, and have spent most of my time wrenching on heavy trucks, so the MB approach is a little new to me.

The 300 feels sloppy compared to the 240, but it never squeaks, just pops.

that would be the quide rod mounts. check out the diy on it. its also known as a tourqe strut mount i belive. yes the guide rod runs from the lca to the rear of the fenderwell. its the mount that wears out

Update
 

While changing the oil and waiting for the old stuff to drain, I did my own inspection of the front end. Left upper and right lower balljoints are clacking. Right upper is squeaking. Bushings are weathered. Front wheels are toed out enough that I can see it by looking at the tires from in front of the car. Right front tire has the innermost tread blocks worn off, and the second row of tread is feathered badly. Front end noises while driving are getting worse rapidly. I won't be driving this car anymore until I get it fixed.

I got to talking to a guy at a different shop, and he thinks the overall price will be less if I buy whole control arms instead of installing ball joints in the old ones. He said it would be 4 hours labor for complete control arms vs 9.4 for just ball joints. I'm going to research parts prices and see what I can come up with.

Over 9 hours for just lower balljoints!? No way, I did mine at a friends shop in a couple of hours, and I was going slow. No spring compressor either.

The uppers, took me a little longer, as I did them in my driveway, and it was dark; but they are actually easier, and should take less time.

$100 won't even cover the upper control arms.

In the case of the upper ball joints, complete control arms are the only option. In the case of the lower ball joints, that recommendation is absurd.

The labor was for upper control arms and lower ball joints, both sides.

After doing some parts research, I came up with:

UCA's $45 ea
Lower ball joints $13 ea
Guide Rod Mounts $50 ea
Guide Rod to LCA bushings and hardware $12 per side
LCA bushing kit (w. sleeve) $23 ea
UCA outer bushings $4 per side

UCA's come with ball joint and inner bushing. I'm still waiting on Phil's price for UCA's.

That's $142 per side for the parts. Labor will still be a biggie. I'll run this past both of the shops I've talked to and see what they quote me. There's also a German car specialist independent in Carson who wasn't answering the phone Friday afternoon. I'd like to talk to him too.

OTOH, maybe the co-worker with the new shop will rent it to me for a weekend in exchange for a 12-pack. I've never done major front end work on a vehicle with independent suspension and coil springs, but I guess it's never to late to learn.

On edit: the whole LCA-replacement idea wouldn't help. I'd have to buy new steering knuckles to get pre-installed lower ball joints. The best price I saw was $432 ea, so this is a non-starter.

I let a local indie replace my passenger side UCA. Somehow, he let the spring rip out the shock, and the spring shot out, almost killing him. Of course, he's never touching my car again, but a spring compressor might not be a bad idea.

The spring compressor becomes essential if the lower control arm bushings are going to be replaced. Otherwise, supporting the car by the LCA's is a reasonable alternative.

The UCA'S come with ball joints but you have to buy the sway bar bushings seperate.

danny