Suspension Noise / Broken & missing lower control arm bolt SOLVED Topic is solved

Post by **800artfreed** » 28 Sep 2022, 17:44

Weird noise from lower suspension while moving the car off the driveway. Kind of a knocking noise. Wife returns later from shopping and brings me a nut with a short piece of broken bolt in the nut. WOW! This was from a broken lower control arm bolt. The long part of the bolt fell out and was missing. The arm was only held in by the trailing mounting bolt!

This was a third party control arm with foreign supplied bolts.

In the past I might have torqued the bolt above recommended specs using impact tool.

I found an OEM bolt saved from previous control arm / ball joint swap to replace the missing bolt.

I think I will rely on OEM bolts for this job in the future.

Post by **abscate** » 28 Sep 2022, 20:13

That’s a really bad failure and kudos to partner for bringing home the evidence

Post by **800artfreed** » 29 Sep 2022, 07:22

: 20220928_160834.jpg (143.58 KiB) Viewed 1491 times

Thought I would show a picture of the "bolt". Notice the dark side of the break. I am guessing that the bolt was cracked for some time. I assume the "clean" side broke yesterday and popped the bolt out of the mount

Post by **scot850** » 29 Sep 2022, 09:42

I'm not clear which bolt you are talking about. Is it the one at the balljoint or one of the ones at the pivot end at the sub-frame? Are your control arms 2 or 4 bolt mounting arms?

To me you are explaining what sounds like one of a 2 bolt control arm? If that is the case I have never heard of one failing before. The balljoint one I have heard failing as people have re-used them. That bolt should never be re-used!

Like abscate says, kudos to your wife on catching that!

Neil.

Post by **800artfreed** » 29 Sep 2022, 13:26

I have 2 bolt control arms. These are probably Chinese manufactured replacement parts.
It was the leading (front) bolt from the driver's side lower control arm mounting it to the frame. The ball joint retaining bolt is fine. I might have stressed the parts while rapidly parking the car on the driveway with the wheels fully locked to make the left turn.
I will examine the trailing (towards the rear) bolt when I put the car back up on my lift. I am carrying a spare bolt and tools just in case of another failure. Due to the discoloration of the sheared bolt I suspect it was cracked at some point prior to the outright failure.

Post by **scot850** » 29 Sep 2022, 15:23

Bolt was bad. I have re-used the inner bolts many times (OE Volvo) with no issues. Your wife was very lucky!

Neil.