beware of loose ring nuts

I have been chasing a strange noise coming from the area of my LR wheel on my 91 348 for several months now. I thought I'd tracked it to a parking brake hardware issue and replaced all of that. I also replaced my rear discs and brake pads but alas, the noise came back, or persisted really. I think I've read just about every thread on the subject, and ran across 1 in which someone described a noise that sounded like a turkey. Sounds odd, but that was a really close description to the noise I was hearing, it sounded like a damn turkey call every once in a while. The solution in the the thread was wheel bearings, and that was going to be my next step anyway, there isn't much left back there.

Anyhow, I pulled the hub knuckle off and got it to my bench. As I was fiddling with the ring nut tool and ring nut on the short axle shaft, because of course the tool didn't quite fit the nut, I realized that I could wiggle my ring nut by grabbing it with a pair of needle nose pliers. The only thing holding it was the fact that it was peened on each side. I removed the ring nut by tapping it out with a flat blade and hammer, so it sure as hell wasn't torqued to 221 ft lbs any more. It was all the way down on the the threads but there was no torque on it. I also read an old thread in which Ernie had the same issue on each side and it ground down the teeth on his the short axle shaft and connecting flange. Fortunately for me, the teeth on the shaft and connecting flange are all good. Everything was where it should have been as far as positioning in the hub so I caught it before some serious damage occurred.

I should also mention that while underway, I could hear a faint high pitched metallic singing noise. I thought to myself it sounds like when a washer isn't secured under a nut and you hear it bouncing. I don't want to say bingo just yet but it sure is starting to fall into place. I have everything apart and am cleaning now, and I have the new bearings for reassembly. Once I get it all put back together I'll report back. For peace of mind I am really thinking about getting into the right side also to check the ring nut on that side.

I'd be curious to know how common the ring nut loosening itself is. Be careful out there!

 

Thanks! That is what I am hoping.

Sent from my SM-T310 using Tapatalk

 

I ordered them from locateballbearings.com, They were around $50 each. The original bearings I pulled out are SKF 62209-2RS2, and I'm replacing with SKF 62209-2RS1. Based on the research I've done, the 2RS2 variant has seals that are able to handle higher temps, but I think they're only available from Ferrari at a much higher price. They are harder to find in any case. There is some good info on the bearing specifics here http://www.ferrarichat.com/forum/348-355-sponsored-bradan/368434-rear-348-355-wheel-bearings-2.html

From my research, either version of the SKF 62209-2RSx will work. My car is not going to see the track so the 2RS1 version is good for me.

Incidentally, I pulled the seal off of one of my old bearings and the grease looks good and they still turn smoothly. I figured since I have it torn down this far and have new bearings I'll swap them out but the old ones really don't look too bad.

 

My pleasure! I've only had my car about a year, but Fchat has been an excellent resource both before and since picking it up. There is so much great info from owners available, if I can contribute I'm happy to. My car has been mainly trouble free so far, aside from this noise and I think the knowledge I gained before purchasing helped me find a car that is pretty solid with good maintenance records. This noise started about 6 months after I got the car, and I've had a feeling it was wheel bearing or related, I was just hesitant to pull the hub until I'd found enough info on Fchat to be comfortable with the job.