I sheered the rear left upper control arm bolt today, without much effort so I guess I am glad that it happened while parked.

I have looked around and cannot determine the size and length of the installation bolts. I looked through the threads and online and found Mercedes part number 910105012001 for the bolt, but that does not help me. I just want to buy compatible replacement hardware at the hardware store. Anyone have that information?

When installing the new control arm, what do I need to do in order to have the default camber? Or is there is only one way of installing the control arm? The front are supposedly adjustable somehow, but I have not found that information on the rears. I don't even have the old one off yet or I would have my answer- the weather is bad here and it is going to be a grind job. I have read that the bolts fuse to the bushing sleeves and am assuming that mine will be fused.

I have read the attached, but removing the struts is not an option right now so I plan to cut the inside boltheads near the springs and pound the bolt outward. I'll install the new bolts with the nuts on the inside. Does that sound reasonable?

 

Aar Sto,

Here is some reading for you - see if this helps out

W163s require special equipment for wheel alignment (particularly, the front - others may disagree with this and comment on DIY.
The rear can be done by ANY alignment shop.

 

That does help, thank you. So I'll need to take care to install the new control arm in the same place on the bracket as the old one, to keep similar camber until I can get it aligned.

What about the bolts? Any idea on a compatible size and length of those? I can guesstimate the length while installed, but don't know the size.

 

How was a bolt sheered while it was parked????????????????

Why can't you buy the correct bolts from the dealer? You just can/t buy any bolt that looks the same as bolts have different ratings.

And yes the bolts are fused to the bushings and you will be pounding at those bolts all day.

 

Take a look thru here

What's you vin#?

 

Dundee,

Fused? Is this the way they come from the factory or just overtime?

 

I sheered it off when removing the nut. Turned a few times with a simple wrench and it sheered off where the taper ends and the threads start. This is in Ohio so it takes on a lot of caustic chemicals in the winter.

I've read in other threads where moderators (Art?) used hardware store bolts - but they didn't list the size. I'm thinking a grade 8 bolt would suffice. I like to use OEM parts so I don't have to do things twice, but I don't have $40 to spend on two bolts shipped.

The VIN is 4JGAB57E84A477428

 

Aar Sto,

The link provided in post #5, is the correct parts # list for your vin.
You should obtain oem bolts, imo. Safety first....

 

Yeah that's the number I came up with in post #1. I agree on the oem but not the german engineering. These bolts shouldn't even be fully threaded, which only creates extra surface area to rust (and fuse to the bushing sleeve), and gives a reduced diameter at the threads.

I did find the sizes, for anyone stumbling onto this thread. The bolt is 910105012001, M12x1.5 90mm. The nut is 913023012002. I found them here also: EBAY

Thank you for the quick responses.

Any reason why I can't install these bolts in reverse with the nut on the inside near the spring? I feel like they should have been installed that way to begin with.

 

Overtime khomer.

 

Yes, because the bushing is different on the ends.

 

I don't want to reverse the bushings, just the bolt direction. I thought the flanged bolt and flanged nut made them identical on each side?

 

I didn't say to reverse the bushings. There must be a reason why the bolts go in that direction. But you do what you want.

 

To follow up, you can go all King Arthur and cut off the rear upper control arms in order to replace them without even touching the struts. Normally you have to remove/move the struts in order to remove the control arm mounting bolts, because the bolts are installed from the inside out.

In my case, the bolt was fused to the control arm bushing sleeve and to the mounting bracket. While the struts do need to be replaced, I need to put that off until the weather gets better.
After reviewing other user's posts dating back over a decade, I used an angle grinder to cut away the body of the control arm. This was supposed to give me room to work. I then bought some thin reciprocating blades and attempted to angle them flush with the inside bracket and cut only through the bolt. This is a horrible approach as the blade catches the bushing and is hard to keep flush. There is also a high risk of damaging the bracket, which is surprisingly thin and malleable. An Amazon review reccommended using a wood blade to first cut away as much of the bushing as possible before then using a more rigid metal blade to cut through the sleeve and bolt. This worked much better.

I reccommend:
Cut zip ties and move all of the wires out of the way.
Don't bother cutting away the body of the control arm for "room to work"
Use a rigid 6" long-toothed (for wood) reciprocating blade to cut away the bushing near the insides of the control arm mounting brackets. It cuts away quickly. The short-toothed metal blades won't work.
Use a rigid 6" metal blade to cut through the bolt and sleeve together. 2 cuts for each cylinder. Change the blade after each cut, at least. You may need to use longer blades if your saw is large or awkward shaped.
Tip: You can use a 9" blade then cut off the end and use it again as a new 6" blade. Dulled reciprocating blades work better than wire wheels at removing bulk rust flakes.


On the driver's side, there is just enough room to insert the bolts from outside inward to install the new control arm. You need to start with the right bolt as some maneuvering of the control arm is involved.
On the passenger's side, there is just enough room to install the bolt outside inwards if you cut a few mm off the end of the bolt. You need to start with the right bolt as some maneuvering of the control arm is involved.