W123 Upper Ball Joint Bad - PeachParts Mercedes-Benz Forum

wordmanjay · #1 01-28-2015, 08:09 PM

My mechanic pointed out the play in my upper ball joints and recommended I replace them.

Do I have to replace the whole control arm?
(I saw that I can purchase the bushings and the ball joints separately)

Thanks in advance for the help.

Diesel911 · #2 01-28-2015, 09:33 PM

You can replace the Bushing on the Upper Control Arm but not the Ball Joint. If the Ball Joint is bad you change out the whole Arm.

However, the real question is if the Mechanic is telling the truth. Meaning is he just saying that because the Rubber Boots are shot or because there is visable movement or you are having other symptoms.

If the Ball Joint on the Upper Control Arm is no good you once the Ball Joint is removed from the Steering Knuckle you will be able to willgle it around easily.

If the upper Control Arm Bushing goes bad "Sagging upper control arm bushings will cause the camber to become negative, resulting in inner edge tire wear."

Below is a pic of the Ball Joint end of the Upper Control Arm and you can see houw it is built into the Arm.

dieseldiehard · #3 01-28-2015, 09:53 PM

I urge you to get a second opinion but don't let this problem go for long.
Find out if its the ball joints are loose, all it takes is a twist of the control arm using large pliers. In my car there was a occasional squeak as there was metal to metal, thanks to Mercedes "sealed for life" lubrication idea

I had a ball joint fail in my '79 300TD. These are $10 maybe $25 each and your safety depends on them. In my case, when the Right side failed on a winding mountain road the car pulled instantly and hard to the right with the tire sitting at around a 45 degree from vertical. I fought the car by wrenching the steering wheel to keep from going into the bushes on the side of the road. If the left side failed I may have been thrown into the path of oncoming cars. It was a very bad experience.
you've been warned!

dieseldiehard · #4 01-28-2015, 09:59 PM

Quote:

Originally Posted by Diesel911

You can replace the Bushing on the Upper Control Arm but not the Ball Joint. If the Ball Joint is bad you change out the whole Arm.

The Ball Joints I am referring to are pressed into the wheel carrier, back side of the hub whatever you want to call that. they are definitely replaceable.

Diesel911 · #5 01-28-2015, 10:33 PM

Quote:

Originally Posted by dieseldiehard

The Ball Joints I am referring to are pressed into the wheel carrier, back side of the hub whatever you want to call that. they are definitely replaceable.

That is the Lower Ball Joint that is pressed into the Steering Knuckle and goes through the lower Control Arm; yes they can be replaced.

The Lemförder/Lemfoerder/Lemforder ones that I bought for Mine were resonabley priced and made in Germany.

It is the same story. If movement in the Joint can be see or the joint can be moved around with no tension on it then the Joint is work. If the Mechanic is only looking at the cracked Boot and declaring the Joint no good that may or may not be true.

Deliveryvalve just posted a thread on the Ball Joints and I think there is a Vid where you can see what a worn one looks like when tested.
I still have dial up Internet and I cannot look at a Video in a resonable time so I do not look.

vstech · #6 01-28-2015, 10:34 PM

Quote:

Originally Posted by dieseldiehard

The Ball Joints I am referring to are pressed into the wheel carrier, back side of the hub whatever you want to call that. they are definitely replaceable.

Those are the lower ball joints, and yes, they are replaceable... The uppers are built into the control arm and must be replaced as a set. Only the bushing and swaybar bushings are replaceable separately on the upper control arm.

wordmanjay · #7 01-28-2015, 11:09 PM

To clarify- I'm talking about the upper ball joint in the control arm.
I've gathered from the comments here that the whole control arm must be replaced, not just the ball joint.

My mechanic gave the wheel an up and down tug and showed me the movement of the ball joints- both sides. In addition, he told me that's why the inside of my tires had worn so badly.

Thanks for the info- I think I've got it from here.

Thanks again.

wordmanjay · #8 01-28-2015, 11:11 PM

Anyone have an opinion on the Febi/Bilstein control arms? They seem to be the most reasonable priced.

vstech · #9 01-29-2015, 12:33 AM

TRW or Lemforder only... All others and you'll be doing it again soon.

Diesel911 · #10 01-29-2015, 01:25 AM

When I grab a hold of the Wheel I find it hard to tell what has paly in it. I am more convinced when other tests are used to find out for sure.

But, I was not there to see it. If there was a lot of obvious movement then they should be replaced. If it was kind of iffy as far as the movement goes I would be inclinded to wait untill some other symptom shows up or you see some Tire Wear issues.

One of the tests in the Manual requires that the Ball Joint shaft be exposed and you screw about a 1 foot rod onto the Joint (special or sellf made tool) and yoy grab onto the Handle and flex the Ball Joint from side to side. When you do that on a good joint you are supposed to feel some tension on the Joint. If not the joint is worn.

You can sort of duplicate the above by putting the Nut on the Ball Joint Shaft and attachaing a Vice grips to the Nut and use that as you would the Rod.

Of course there is other tests.

Stretch · #11 01-29-2015, 01:40 AM

Quote:

Originally Posted by Diesel911

...
Deliveryvalve just posted a thread on the Ball Joints and I think there is a Vid where you can see what a worn one looks like when tested.
...

Here's the link

Videos of a w123 in need of a suspension rebuild

Quote:

Originally Posted by wordmanjay

Anyone have an opinion on the Febi/Bilstein control arms? They seem to be the most reasonable priced.

Febi are cheats - they price themselves in a "reasonable" not too cheap not too expensive price range but the quality is usually cheap. I've had nothing but trouble with Febi rubber parts. I've had nothing but trouble with their Benelux area manager.

Quote:

Originally Posted by vstech

TRW or Lemforder only... All others and you'll be doing it again soon.

I've seen some dodgy TRW stuff and some good - so tread carefully there.

Diesel911 · #12 01-29-2015, 09:07 PM

One way to check the Lower Ball Joint is to support the Lower Control Arm on a Jack Stand high enought to lift the Wheel off of the Ground with enough room for a "Bottle" Hydraulic jack to go under the bottom of the Steering Knuckle (Tire needs to be removed to do this I think).

If the Joint is good as you pump the Hydraulic Jack you should see no upward movement of the Steering Knuckle.
the same might be done with a Pry Bar but if you are by yourself it is harder to observe. A Book I have shows using a Pry Bar under the Tire to pry it upwards but you cannot do that and look at the Joint.

The same Book shows the type of Ball Joint and Spring setup the Mercedes has tells you to move the tire up and down to find the Ball Joint Play not rocking the Tire in and out.

Not sure how to check the Upper Ball Joint. Depending on how the Car is jacked up the Sway/Torsion Bar is going to put pressure on the Arm.

Diesel911 · #13 01-31-2015, 03:04 PM

I used one of the Computers at the Library to view the Videos on the loose Ball Joints.

Those particular Ball Joints were exceptionally Bad and easy to see but the methods are still valid.

As I said one of the ways to check the Ball Joints in the Manual essentially had to do with attaching a rod to the Ball Joint Shaft itself and flexing the joint to see if there is resistance to the flexing or not.
The above flex test I believe would find a loose joint long before it gets to the state that the ones in the Video show.

Unfotunately to do that test the Joint shaft has to be pressed out to do it.