I agree as well. I'll pick up the UCAs this week. I'll cut the bolt off of the existing UCA and just replace the whole thing. Is the UCA replacement something I can handle in the driveway? I know the bolt connecting it to the frame can be tough to get out. I tried unscrewing my bolt this last weekend and it does unscrew out pretty easily. Does that mean that it's not stuck to the sleeves and that I won't have any issues removing the entire piece? Also, the UCAs I've been looking at have the bushing already on where the UCA connects to the body, but no bushing where the UCA connects to the torsion rod. Do I need to get this bushing or is that part of the torsion bar? What is this bushing called? Any other parts I would need? Huge thanks to all of you.

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Alex
1984 300CD - Silver/Blue - 326,000 miles (sold)
1979 240D - Canary/Brown - 221,222 miles (I love this car)

If the UCA bushing has not completely disintegrated and the bolt moves, there isn't too much difficulty in replacing the UCA. My only advice is to use a tapered alignment pin to find the hole and center it with respect to the body before you struggle with getting the bolt installed. Getting the bolt in and out of the left side can be a bit of a challenge due to the location of the brake reservoir. I needed to remove one of the brake lines to get sufficient clearance on the left.

The UCA does not come with the stabilizer bar bushings. These should be replaced and are of minimal cost.

While you are in there, check the condition of the stabilizer bar. They rust on the end over time. Use a heavy wire wheel and remove all evidence of corrosion and then paint the end of the bar with POR-15. You don't want to know about the misery that will occur if the bar breaks.............

http://catalog.peachparts.com/ShopByVehicle.epc?q=&yearid=1984@@1984&makeid=63@@MERCEDES+BENZ@@X&modelid=6170%3AMBC%7C1496%3AED%7C10000135@@300CD&catid=241464@@Suspension&subcatid=241504@@Control+Arm+Bushing&applicationid=W0133-1642615&mode=PA

Note that you need two per side.

To avoid possible confusion, I suspect that you mean outer UCA bushings. Stabilizer bar bushings are a different breed of cat.

I loathe the term "UCA bushing" for those items.............it implies that the the bushing that secures the locating bolt to the body is replaceable.

I really question the use of that term when the bushings are utilized on the stabilizer bar.

Thanks, guys. Brian, the stabilizer pin is used to line up the holes on the control arm with the body, correct? Is that all it's used for? Also, I have no experience removing the brake lines and assume this would mean plugging the lines so the fluid doesn't come out and then bleeding the system? If so, I might as well learn how to flush and replace the fluid in the system (it's black)?

Tango, the bushings I would need are the ones that connect the UCA to the torsion rod. The bushings go in the middle hole of the control arm. Are these the "UCA bushings" you linked me to?

Would I need anything else (i.e., washers, bolts, etc.) to get the job done? According to the FSM, it's a simple process.... What a can of worms...

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Alex
1984 300CD - Silver/Blue - 326,000 miles (sold)
1979 240D - Canary/Brown - 221,222 miles (I love this car)

I just checked the DIY article on Diesel Giant, makes things super clear. I guess they're called "outer UCA" bushings. Looks like it's going to be a pain to get these bushings in right. And I still have to try to figure out the brake line issue. Maybe I can work around it, I'll check the car tonight to see what kind of clearance I have.

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Alex
1984 300CD - Silver/Blue - 326,000 miles (sold)
1979 240D - Canary/Brown - 221,222 miles (I love this car)

Apparently, that's the terminology............although I don't agree with it.

Installing them is no issue. One goes on the bar............the UCA is installed onto the bar............and the second one then goes on the bar to secure the UCA.

You might be able to avoid removing the forward brake line if you've got small hands.

You should not need to remove brake lines on a W123.

Yes.

Absent seized up parts, replacing the UCA's is incredibly simple. All that is needed is the left and right UCA's and the four outer bushings.

If you mean the inner UCA bushing, there should be no problem with the alleged implication; that bushing is replaceable.

Problem is, those are not the only bushings associated with the stabilizer bar. There are a couple more that secure the bar to the frame.

Are you referring to the bushing between the UCA and the body? Is this replaceable on a W123? On the W126 it is part of the UCA and not replaceable.


Yes, another set of stabilizer bar bushings................

1984 300SD/1987 300SDL Upper Control Arm Inner Bushing

http://catalog.peachparts.com/ShopByVehicle.epc?q=&yearid=1987@@1987&makeid=63@@MERCEDES+BENZ@@X&modelid=6213%3AMBC%7C1512%3AED%7C10000100@@300SDL&catid=241464@@Suspension&subcatid=241504@@Control+Arm+Bushing&mode=PA

http://catalog.peachparts.com/ShopByVehicle.epc?q=&yearid=1987@@1987&makeid=63@@MERCEDES+BENZ@@X&modelid=6213%3AMBC%7C1512%3AED%7C10000100@@300SDL&catid=241464@@Suspension&subcatid=241504@@Control+Arm+Bushing&applicationid=W0133-1628670&mode=PA

Attached Thumbnails

 

I'm a bit confused by those components. One appears to be a replacement for one side of the UCA where it meets the body? The UCA typically has this bushing pressed into the arm during manufacture of the arm. Is this one bushing replaceable............the inner.............and not the outer?

What would be the purpose of replacing the bushing when the ball joint is not replaceable?

The second photo shows the replaceable bushings for the stabilizer bar...........referring to them as "outer control arm bushings."

The 123/126 UCA uses two identical inner "bearings" (MB Nomenclature) one forward of the UCA and the second one rearward of the UCA on the UCA chassis mounting bolt. These inner "bearings" are replaceable either singly or in pairs as necessary. The outer "bearings" are also replaceable.

The purpose would be to R&R only the failed portion of the assembly. With the general decline in the quality of aftermarket parts one might elect to replace only the failed sub-part of the higher quality original MB part assembly that is otherwise suitable.

The lower photo listing as outer control arm bushing is also referred to by MB as a “bearing” and is the “rubber only donut” used to construct the semi-flexible connection between the UCA's outer opening and the outer ends of the torsion bar.

So, if I got the terminology correct, the two "inner bearings" function to secure the LCA to the body and the two "outer bearings" function to secure the stabilizer bar to the UCA.

I have to tell you...........that terminology is ridiculous.

Good to know that you can replace those bushings if needed............thanks for the info.

^Agreed, you a degree in the German language!
But it's just easier to replace the complete UCA, you get a new ball joint.

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83 SD

84 CD