need help quick, stuck nut
 

Hi all,
I was attempting to change out the old shock/spring assembly from the rear end of my ML. The nut that bolted the shock to the lower wishbone get stuck. The problem is I need to use a Torx T-30 to hold the shaft while turning the nut. I have managed to sheer off 2 of those T-30 torx bits. I was able to loosen it only ended up having rust trapped in the tread and the nut got stuck. I cannot turn it either way without breaking another torx bit. Any suggestions will be greatly appreciated. Surely, plan B will be the mechanics with the power tools.

thanks

steve

Do you have the strut assembly out of the vehicle and you want to replace the shock with a Bilstein and re-use the spring?

Are you trying to take the strut assembly off the vehicle?

When I did this job I don't recall having had the problem you're expeniencing. I may not be visualizing your situation correctly. I think to get the strut off you just remove the three nut on the top and the nut on the bottom. I used an impact wrench and the bottom nut just spun right off.

yes Ron, I am replacing the who strut and spring assembly (1 piece). 3 nuts on top, not a problem, I got them out in no time. The bottom nut that attached to the lower wishbone is giving me *****. you know, it needs the torx T-30 to counter hold the shaft so that you can turn the nut. The freaking nut just drove me nuts. It is stuck really good, I broke 4 of those torx bits already, I will break all the torx bits available on earth and still won't get it out. I was trying to turn the nut back (i.e. tighten) so that I can clean the rust out of the tread, still the damn nut just won't turn.

Now I don't remember for sure how I did it buy I think I loaded the suspension by jacking it up by the ball joint with a floor jack, otherwise, you are trying to remove that bottom nut with all the forace of the spring and shock pushing down so it's real hard to loosen. Does that make sense?

I did use a impact wrench to undo that nut and all I can say is life is much better with air tools.

Use PB Blaster or other type of penetrating oil to help you out. I now give everything a shot about 5 minutes before I start working on it.

I have no particular experience with your situation except this.

Are you certain it is a Torx and not a triple-square. Just went through this when replacing the axle in my 300E. Triple square has twelve internal points.

Steve

It shouldn't make any difference whether you jack up the ball joint or not, the shaft that goes through the lower wishbone can spin by itself. You still need to counter hold the shaft somehow while using the impact wrench don't you?

surely not triple square, I have the new strut/spring assembly to verify, it's a torx.

No, not necessarily. Often times the impart hits it so hard it just comes off without any counterhold. Depend on how good your impact wrench is and how stubborn the nut want to be.

I've got my old strut assemblies around here somewhere, I'll look for them tomorrow and see what the top of the rod looks like. I really don't recall having to counterhold them at all.

thanks Ron, I don't have an impact wrench. that's probably the biggest hassle I have. The other thing I regret that I didn't do was to clear the rust on the shaft before wrenching it on.

I feel your pain....when I swapped my spring/shock assemblies that nut came off with no problem. Here's a couple of ideas to remove the nut......

let soak overnight with PB Blaster or Sillikroll to loosen.....then try

heat up the nut with a blowtorch.......just for a few seconds to allow it to expand, then try turning it..

lastly.........using a hacksaw you can cut a groove in the base of the threaded shaft and use a large screwdriver instead of the torx bit for better purchase

In all of these suggestions, I think I would try turning clockwise (tighten) to return to original position and then take a wire brush to thoroughly remove any rust/corrosion before attempting to remove again.

Good luck and keep us posted ..........

Photo of the top of strut below. 1999 ML 320 build date of June of 1999, (one of the last 1999's made before the factory shut down and tooled up for the 2000 model).

The sides of the top of shaft have 2 flat sides, so you would have to use an adjustable wrench or something. I did not use any counterhold. You can see the grease and dirty on the sides of the shaft, indicating no tool had been placed there.

I used a Snap On 1/2 drive IM6500HP impact wrench. That nut just came right off.

That is not the nut he is talking about, he is talking about the one on the bottom of the strut that holds it to the wishbone. You need to hold the bottom stud in order to get it out, as the stud is part of the creaking ball joint, and just spins if it is not held, as the spring exerts no pressure on it. I had the exact same problem with mine, only instead of stripping out the torx tools, I stripped the stud! I ended up cutting it with a hacksaw blade (blade only, no handle as it is tight quarters in that area) and suing a flat blade screwdriver along with a tourch to heat it up. Worst case scenario, you can drill out the stud and crush the nut to get it out. Just be careful not to damage the wishbone.

DCF, you are the man! knowing exactly what I am talking about. I just sprayed some PB blaster to the nut and will give it a try in the next 20 minutes or so. If it fails, I think I will get a drummel and cut the damn nut in half

Are you talking about the bottom of the strut that goes thru the wishbone?