While upgrading the front suspension this winter, I decided to go in for new tubular front control arms. I looked at all the major suppliers and chose the BMR arms for a couple reasons. I installed them a couple weeks back up now I am getting a THOING noise and spring resonance with compression and rebound of the front suspension. Its pretty clear which spring it is and it varies depending on the road condition.

I put the car up and noticed rubbing on the side of the spring where it goes into and comes out of the spring cup on the arm. In compression, the coil catches the lip of the spring cup in the arm and holds it up momentarily. When it "uncatches", you get that noise. This only happens on the outside of the spring cup towards the spindle as the angle of the arm with the spring pushes it to the outside of the cup.

Has anyone else run into this with BMR (or UMI) arms? Wish I could fix it without removing the springs as getting them back in place is a bear.... I was thinking about grinding the edges back at an angle to prevent the catch... annoying as heck to hear that "THOING" when driving.

 

Have you tried rotating the spring? say 45 or 90 degrees? move the offending coil away from the lip.

 

Springs need to be properly indexed with each other so no rotating.
trim the bucket, its all u can do.

 

Well the two springs are at 90 deg from each other; based on the end of the coil in the pocket and it occurs more with one than the other, so I suspect there may be a better position available.

Turning the springs has been a bear. After compressing the spring, I lower the arm and turn as best I can using vicegrips (NOT sticking my hand in there, had the compressor let go once....OUCH). The one I rotated has been better but still get the noise on larger amounts of suspension travel.

Man do I HATE front springs.....

 

I went back to stock suspension years ago and never looked back. Have you attempted to talk to bmr about the issue? although it sounds like incorrect installation. as 86ta says index them. I dont know if i would try to actually rotate them in the car lol...remove it and reinstall it in the position you desire.