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I purchased mevotech upper and lower control arms to hasten my front end rebuild. As I was tighening down the lower shock bolts to the arm to the factory 48 ft-lb my torque wrench would not click and I noticed the bolt only getting longer. The torque load never increased. I took it all apart and confirmed the box frame of the arm is being crushed. Looking through the hole compared to my OEM arm, I see its missing a steel gusset for support. Checked my other arm which I had not installed yet and same thing. Looks to be a design defect/oversight. So my options are return and rebuild the original. Or just not tighten to the factory spec. Say 30-35 which I can get to click and double up on lock nuts? Thoughts? I have not seen this mentioned as an issue in any thread that I could find.
Very interesting.. I'll need to shine a brighter light to see if there are any offset or simply not there. I didn't look beyond the hole perimeter. Either way I cannot torque to factory specs without deforming the arm.
Very interesting.. I'll need to shine a brighter light to see if there are any offset or simply not there. I didn't look beyond the hole perimeter. Either way I cannot torque to factory specs without deforming the arm.
Looking through the largest hole on the bottom I actually can see a vertical piece, but like yours it's not adjacent to the bolt hole so I didn't see it initially. But it's for sure only on one side. Either way for me it didn't appear to allow me to torque to spec without giving way. Did you try installing yours yet?
Would you be able to provide some comparison photos of this internal strength gusseting? CMS501138/9 have been benchmarked from OE GM lower control arms, and while the parts are of relative age, we have not been made aware of any issues regarding any flexing of the control arm materials. Regards, MIGUEL NIETES SENIOR TECHNICAL ADVISOR
I will take more detailed photos and get back to them and maybe a video of it yielding under 48ft-lbs. I'll reply back when I know more.
I didnt bother, I went straight to making spacers to distribute the load over more area. Not the best solution but should work. Eventually going to go with umi control arms.
I'm installing coilovers so I can adjust for the height difference.
Figured I'd update this. The replies are in order.
1. Would you be able to provide some comparison photos of this internal strength gusseting? CMS501138/9 have been benchmarked from OE GM lower control arms, and while the parts are of relative age, we have not been made aware of any issues regarding any flexing of the control arm materials.
2. The photos did arrive and I’ve brought it to engineering’s attention to investigate this further. From what I’ve been made aware of, we are using a higher strength steel which does not require the use of an internal gusset, however it looks like they will need to look into why the mounting surface is curved instead of flat. 48 ft-lbs on high strength steel won’t be enough to straighten the surface, nor will the hardware be adequate to allow for over-torquing to straighten the material.
3. A lot of manufacturers do suggest replacing the lower strut cross shaft hardware when replacing the parts. While the GM factory service manual doesn’t say that for a vehicle this age, modern GM vehicles with similar suspension types do. Depending on the mileage on the vehicle, it may be worth replacing the hardware as preventative all together.
During this back and forth I provided pictures. I noticed too using a straight edge that the mounting surface was in fact not flat as compared to oem. With it off the car I used my old shock and was able to get it to lock down at 48 ft-lbs. I think I bent the surface a bit already as from here it didn't take too long before I got it to click. With the shock mounted, I see it pulled itself flush to the arm in the end. I think it's fine, but definitely not identical to oem. I was pleased with their support. Very articulate and quick to reply. Usually within a few hours once someone grabbed the email.
I'm thinking about drilling the holes out to accept a metal sleeve, sliding the sleeve in the larger holes, and welding them in. Might be overkill but worth a shot.
I just bought these too and good catch @timaishu
Do you all think using washers would work to help distribute the pressure when tightening the bolt?
As far as I could tell from a pure visual check, it seemed like the flex was from the top surface of the arm. Mine wasn't totally flat my oem. I think the extra turns on the nut was from the arm flattening under the rectangular shock mount on the top surface. I didn't notice any movement on the button. The bottom also has two sheets of steel under the bolt so I assume that part was fine.
05-28-2022, 06:23 PM
mevotech lower control arm design issue 
