Front crossmember clunk - permanent fix?

[madmax032]

Good Morning! My 2016 2wd has had an obnoxious clunk under low speed braking and low speed/stationary steering conditions. After some searching and a tip-off from Google, I found that it was likely caused by my front crossmember moving around. I checked it out and could see the witness marks where the bolt heads had been moving around in their holes. I checked them with my "normal" wrench and they were tight so I got my 25" breaker bar on them and tightened the crap out of all 4. That "fixed" it/shut them up for now but since crossmember previously started moving around with already tight bolts, I imagine it will start to move around again. My question is, has anyone found a permanent fix for that particularly obnoxious (albeit relatively harmless) crossmember movement? I've considered trying to drill out the holes larger and throw some bigger grade 8 bolts in but that seems a bit overblown.

 

[Doubeleive]

Good Morning! My 2016 2wd has had an obnoxious clunk under low speed braking and low speed/stationary steering conditions. After some searching and a tip-off from Google, I found that it was likely caused by my front crossmember moving around. I checked it out and could see the witness marks where the bolt heads had been moving around in their holes. I checked them with my "normal" wrench and they were tight so I got my 25" breaker bar on them and tightened the crap out of all 4. That "fixed" it/shut them up for now but since crossmember previously started moving around with already tight bolts, I imagine it will start to move around again. My question is, has anyone found a permanent fix for that particularly obnoxious (albeit relatively harmless) crossmember movement? I've considered trying to drill out the holes larger and throw some bigger grade 8 bolts in but that seems a bit overblown.

the design has been pretty much the same for 20 years, my dealer said they usually just take the bolts out swap them around and re-torque.
I even had a lower control arm make a egg shaped hole in the frame (that one took a long time to find), my fix was to have a big @ss washer welded on the rear end of the hole since there was plenty of bolt length and that fixed that.

 

[Fless]

Start by properly torquing the bolts. Specs can likely be found on www.lemon-manuals.la.

 

[madmax032]

I dropped out the crossmember, thoroughly cleaned off all of the contact points (scraped and blasted off wax with brake cleaner) and found that while the holes are not egged out, the metal from the outer brackets is warped/pulled in a bit. The outer brackets are not flat as a result so the clamping points are kind of compromised. I reinstalled and tightened the bolts to 52 ft/lb + 110 degrees and big surprise, it still still clunks-not as severely though.
Next plan-I ordered a set of thick, hardened washers to potentially spread the load around the warped area and when I get the washers and have some time, I'll try installing them and torquing to spec again and report back. What a stupid problem... :/

 

[madmax032]

Only time will tell if this is the ultimate fix but I shoehorned some grade 8 5.5" 1/2-20 bolts in the holes and put big grade 8 washers on each side to spread the load along with some grade 8 torque lock nuts from NAPA. Since the thread pitch is different than stock (fine thread) and they aren't stretch bolts, I settled on 125 ft/lb and so far, so good. Since 1/2" bolts are close to 1mm thicker than the stock bolts, there's less wiggle room so that has to be good for something. I originally wanted to do this up on ramps but that causes the crossmember brackets to spread so I had to jack it up from the frame.