w123 front suspension: what is this part and do I need to replace?
 

I've been having what feels like an unbalanced wheel on what feels like the front left on my 1985 w123 300td wagon. It only shows up above 50mph and seems to lessen around 75mph. I bought new tires and no change. I decided to replace the front shocks and in doing so noticed what I think might be a worn part that needs replacing (centered in attached pic). What is this part called? I see shiny metal where the rubber has ripped and I am assuming this is not good? Could this be causing my problem?

Ball joint, needs to be replaced. You probably need to replace both the upper and lower on both sides.

X2

Your picture is of the lower control arm ball joint, MB Part number 1163330927.

Right upper control arm, MB Part number 1233304707.
Left upper control arm MB, Part number 123304607.

MB suspension parts are pricey.

Before ordering any parts (avoid URO, BTW), it may be worthwhile to have the front suspension inspected by a trustworthy mechanic or alignment shop that has had experience with W123s.

This way you have a complete idea of what is needed to bring your front suspension up to a safe condition for the minimum outlay.

You don't want to replace a part, go in for the alignment afterwards and find out the alignment can't be done because of other worn parts that must be replaced.

I agree with both posts.

But its unlikely causing the vibration.


I recommend you pull the rotors, clean out the grease, replace the inner and outer wheel bearings, and grease seals.

Also, a dragging caliper can cause it.

Inspect for signs of heat...

agree with all three posts...
the worn tie rod ends will not technically cause a vibration... but will allow a little one to really be felt...

Oh... fyi... setting endplay on new bearings is a task that needs a VERY experienced hand, or a dial indicator and base...

Does his car have ' crush ' rings on the front wheels ?

Haven`t heard of a Crush Ring for the front wheel on a W123, What is it?

The rear wheel bearings have a crush seal or washer.

I recently did the front suspension on 2 SDs. Both cars, one of the bolts the hold the UCA and the LCA to the body would not come out. The final solution was to use a sawzall to cut through the bolt. It was easy once the decision was made and new blades were purchased.

I also decided to change every thing except the tierods and drag links which were almost new and easy enough to change and don't require the spring to be out. Both cars drive wonderfully. Lemforder has been frequently recommended but aren't always available. Take your cances if you don't want to spring for OE parts. I don't have enough mileage to say how long the repair will last but the car is enjoyable again.

My ball joints looked exactly the same as yours and they had big time play in them, so I decided to replace them. Upon expecting the front end, I noticed that every part was basically worn out. So I ordered everything, lower ball joints, upper control arms with ball joints already installed, tie rods, drag link, guide rods, control arm bushings, and idler arm bushing, all Lemforder. I basically spent close to $550 in parts alone. If i only had the ball joints replaced at a reputable independent MB mechanic, it was in the neighborhood of around $400. I couldn't imagine what the cost would be if the front end was totally rebuilt at the same shop. The hardest part of labor for the front end was removing and installing the front coil springs. Everything else was easy. I did bring the the old lower ball joints and control arms to the MB shop to have them press out the old ball joints and install the new ones, cost $40, money well spent. Once everything was put back together, I had a wheel alignment done and everything is so much better!!!
My front end is so much tighter, especially when the suspension is articulating, in turns and when going over bumps.
I highly recommend getting your front end rebuilt, whether you do it yourself or at a shop, and use either MB parts or Lemforder, and you will be set!!!

Indeed on th back the "fit only once" bearings have a crush ring spacer thing much like the differential pinions. The front wheel bearings are adjusted by simple screw tightening - it is, however, quite easy to bugger up this adjustment and not have the correct bearing clearance.

(But for the case of this thread I'd be looking at the knackered ball joint first)

It has been 15 years since I had my wagon.... I just remember messing up the first adjustment and being glad I bought two spare crush rings...

No way to tell if the ball joint is worn from the photo in post 1. Rubber boots often slide up like that when the front wheel is hanging. Typically, loose ball joints cause a "cupping" wear of the tires (Google Images).

You need to use a pry bar to see if there is any noticeable play in it. If you see the boot torn, replace it since required to keep water and dirt out. Also squirt in new grease. If no fitting for that, there are syringes for a lube gun. To replace the boot, you must pull the b.j. stud out of the spindle. I used a pickle fork - had to buy one w/ narrower opening ($10 O'Reilly's) and cut the tips off so they didn't bottom out on the spindle behind it. A re-boot (polyurethane is best) is much simpler than replacing the ball joint (many posts).

Over here they have stopped selling the boots. They say it is for "safety reasons". I think it is for profit reasons...

...unfortunately in my experience a broken boot does indeed mean nadgered ball joint but like you say checking is always worth while