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@Crya I have what may be a really stupid question here. The inboard bolt/nut that attaches the thrust arm to the chassis - the bushing end. Did you turn the bolt or the nut to remove? I’ve been cranking at the bolt head and it won’t budge even a little and I’ve probably put over 400ft/lbs on it. Before I put a torch on it..... is it possible that the bolt is flat-sided and doesn’t move, and only the nut turns? The bolt that’s in there is a standard hex head, 22mm, not a torx as shown in your photos or in WIS. The nut is in a little metal cage, which I assume is attached to the mounting bracket to keep it from moving, and I don’t see how I can possibly crank at that side. Thanks for any ideas here.
Hey man. I’m pretty positive I worked the nut. It’s still tricky getting a tool on the nut in that small space but I managed so I’m sure you’ll get there. Good luck!
2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
Originally Posted by Crya
Hey man. I’m pretty positive I worked the nut. It’s still tricky getting a tool on the nut in that small space but I managed so I’m sure you’ll get there. Good luck!
Ok thx will try that. Was your nut in a metal cage or bracket too? It wouldn’t appear that the nut is turntable. I’ll take a pic when I get back home in an hour.
And do you remember if the bolt itself is flat-sided or otherwise non-turntable?
What would be the reason or benefit for what hardware they put in there I wonder? Must have needed to replace and that’s what was available in shop? Anyways. Sucks you’ll have to cut it out but hopefully that will be the end of it. Although I had a mother of a time get the bolt back in for lack of clearance near my home ol cooler line. I don’t think your model has that same setup hopefully
2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
Originally Posted by Crya
What would be the reason or benefit for what hardware they put in there I wonder? Must have needed to replace and that’s what was available in shop? Anyways. Sucks you’ll have to cut it out but hopefully that will be the end of it. Although I had a mother of a time get the bolt back in for lack of clearance near my home ol cooler line. I don’t think your model has that same setup hopefully
Nah I have tons of space to the 44O cooler.
Interesting notes from WIS. 1) it says to unfasten the cooler so you can move it around for your bolt, and 2) right underneath it says to NOT turn the bolt.
2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
I’m so dumb. That’s a KMAC bolt in mine. And the reason I can’t get it out is that my guy in NJ had to make it crazy magilla gorilla tight so they wouldn’t slip under load. And those “fingers” are bent into place once everything’s together. What a stupid system.
Can’t get a wrench or socket on the bolt side, zero space. If I try to heat and snap the bolt head, there’s no room to take the bolt out through the other side. If I take the sawzall to the bushing and can’t get through the bolt I’ll really be screwed. I’m really at a loss now. Might just put everything back together and let it be someone else’s problem, hopefully with better tools.
2012 C63;1971 280SE 3.5(Sold);2023 EQS 450 SUV 4 Matic (Wife's)
Jim, that is a KMAC bolt, nut, washer and bushing you are dealing with and trying to remove. The bolt has a flat on it that turns the bushing to adjust. No wonder you cannot turn it with the nut still tight on the other end. You will need to remove the nut, which has a KMAC locking washer on it. The washer has a flat on it locking it to the bolt as well. Take a coal chisel or old large screw driver and tap it in there to open up the flats on the lock washer. The washer is mild steel and will not be too hard to bend back, just give it a good hammering with the screw driver or chisel as a lever. Once you have the washer flattened out remove the nut and tap the bolt out. Someone did a good job bending the flats on that washer to lock it in place. I didn't even bother on mine because I know what a pain they can be to straighten back out to get the nut off again. A little BF&I will go a long way to get those flats straightened back out and then you will be good to go.
2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
Originally Posted by Mort
Jim, that is a KMAC bolt, nut, washer and bushing you are dealing with and trying to remove. The bolt has a flat on it that turns the bushing to adjust. No wonder you cannot turn it with the nut still tight on the other end. You will need to remove the nut, which has a KMAC locking washer on it. The washer has a flat on it locking it to the bolt as well. Take a coal chisel or old large screw driver and tap it in there to open up the flats on the lock washer. The washer is mild steel and will not be too hard to bend back, just give it a good hammering with the screw driver or chisel as a lever. Once you have the washer flattened out remove the nut and tap the bolt out. Someone did a good job bending the flats on that washer to lock it in place. I didn't even bother on mine because I know what a pain they can be to straighten back out to get the nut off again. A little BF&I will go a long way to get those flats straightened back out and then you will be good to go.
Thanks Mort for confirming what I eventually concluded. Those stupid fingered washers ugh. Well the locking system works LOL
The problem is that I can’t get a wrench or socket on that nut. There’s just no clearance and the swaybar is in the way too.
I’ll get back under and see and see if I can figure it out. Thanks for the tips!
2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
You forgot to add tons and tons of cursing Mort. What a horrible spot to have a locking mechanism like that. I guess if I had it up on a lift that would be easier, but man..... Got the tabs folded out of the way. Tomorrow is finding a 23mm offset box wrench and hoping I can get enough leverage on that sucker to break it free. I only have maybe 2-4” of movement as the wrench will be snaked between the swaybar and the tie rod. I just don’t see that happening.
Last question for this hijack Mort (sorry). Can I turn that bolt now to unscrew it, or is it shaped in a way to only turn the bushing? Thanks
2012 C63;1971 280SE 3.5(Sold);2023 EQS 450 SUV 4 Matic (Wife's)
You must be able to get a wrench of some sort in there. Get a wrench with a box and an open end. One end or the other should work. You might run out of room for the box end between the nut and chassis mount. It should not be that hard to loosen but should have have about 90 lb-ft on it.I know it is tight but it is the only way to tighten up the nut so someone must have figured out a way to get it tightened up in the first place. The bolt has a flat on it to turn the bushing so you can't turn it to tighten or loosen the nut you have to turn the nut and remove it then find a way to tap the bolt straight out. It is a really tight spot to work in but it can be done. I am pretty sure the wrench is 22mm. I always generate a little or a lot of blue air on jobs like these...lol. GL
There are 3 tabs on the lock washer make sure they are all released.
You will be able to get on it without too much trouble from out side the swaybar and the wrench is 22mm. I just reached under the car with it sitting on the tires and was able to get an open end wrench on it.
2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
Thanks Mort. Will try again tomorrow morning. My 22’s (open end, box and flare) aren’t fitting on it for some reason even with all 3 tabs out of the way, they seem just fractionally too small. Possible that the far side I can’t see is rounded off or marred up or something. Appreciate your tips, hopefully I’ve got this out tomorrow and on to the next thing...
That’s correct I did need to use various offset wrenches till I found one that would let me make about 1/4 turns at a time. It wasn’t fun. And now it’s all coming back. This is the project where I dropped the wrench on my face and gashed my head. Awesome. Your situation is far worse given your locking nut debacle but at least now you’re back to baseline. The right wrench and you’ll be home free...kinda.
And thanks. Glad to know it wasn’t just me that thought this two bolt job was actually more difficult than you’d think from observing the part.
2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
Nut off. Thanks Mort, the 7/8 wrench was a perfect fit.
Been hammering at the bolt for 2hrs. It turns freely and spins the bushing with it, but won’t come out. Seems that the bolt is seized to the bushing sleeve. I’m pretty close to taking the sawzall to it. What a mess.
Nut off. Thanks Mort, the 7/8 wrench was a perfect fit.
Been hammering at the bolt for 2hrs. It turns freely and spins the bushing with it, but won’t come out. Seems that the bolt is seized to the bushing sleeve. I’m pretty close to taking the sawzall to it. What a mess.
Happened to both of mine as well... one eventually hammered loose the other I had to grind thru the bushing and the bolt to break loose
Nut off. Thanks Mort, the 7/8 wrench was a perfect fit.
Been hammering at the bolt for 2hrs. It turns freely and spins the bushing with it, but won’t come out. Seems that the bolt is seized to the bushing sleeve. I’m pretty close to taking the sawzall to it. What a mess.
Liquid wrench and an air hammer.
If you're replacing the bushing, use a torch then a spray bottle with cold water.
Damn you guys in corrosive environments? My 10-year old pieces just popped right out by hand. Now I feel lucky compared to what you guys went through! Good luck Jim. Would love to see how it all comes together.
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