Trailing Arm/Banana Arm Bearing Noise (74)

[moneymanager]

Been chasing a groaning/scraping noise in my 74's rear suspension for a while. It's usually heard when turning at low speed.
For the record: it is not the shocks, the engine sheet metal rubbing the body, my aftermarket sway bar, or the starter touching anything. All of these have been removed or disabled or otherwise carefully checked.
It might be my Elephant PolyBronze spring plate bearings. But these have been removed, refitted, lubed, properly shimmed 3X's without much effect. More to the point, my noise is not a squeak, which is what others report, but a groan/scraping sound which no one I know has complained of from these bearings.
There's nothing left back there that moves, except the trailing arm/banana arm bushing at the front/center of the car. Several people have told me those almost never make noise. I'd welcome comments from anyone who's suffered from worn/noisy trailing arm bushings.

Three weeks later: the problem was NOT the Elephant product but the trailing arm bushings... very noisy. A nice dollop of spray silicon quieted them for the moment.

[steely]

Wheel bearing?

[ginot912]

I have similar noise in slow turn, into garage usually. I think it's in the parking brake stuff.

[moneymanager]

Wheel bearings usually make a rumble at speed, not my problem but thanks.
Should have mentioned parking brake; pulled apart and readjusted a few months back. Seemed ok.

[Tremelune]

Curious to know if you find the problem or go insane first.

[moneymanager]

So far insanity seems a more likely outcome.

[tshebib]

My vote is limited slip diff. groaning as you make the slow tight turn.

[HawgRyder]

I vote for the differential.
Slow turns make the diff do its thing at a slow enough speed that wind, road noise, and engine revs are not a factor.
Some types of positive or locker type diffs can be very noisy.
The old Detroit Locker in my Ford had a very loud "clunking" in slow sharp turns...it was the locker locking and unlocking several times....almost sounded like the gears were broken...people used to laugh...thinking it was on its last legs.
Try raising the rear end off the ground...and turn one wheel to get the diff to do its thing...tell us what that sounds like.
Bob

[gregwils]

You could always try a chassis sensor. I made one that has helped rule stuff out - steelman makes one. I fabbed one based on a thread/video I found. It's basically a mic, like the ones used as a pickup in an acoustic guitar, then broadcasts to a speaker or headphones. If you google "chassis ear" you will find lots of sites/forums to review.

It might work reasonably well since it's at low speed. I would be happy to take a swag for you, which will have little to know relation to the actual issue, but I really recommend some tool to help isolate the source. I am replacing my driver banana arm this winter based on my findings. Good luck.

[moneymanager]

Thanks for the thoughts. Differential and parking brake and wheel bearings seem just fine. I was about to go with the chassis sensor when an idea occurred. I emptied an entire can of silicon spray on the small rubber bushings at the front of the trailing/banana arms. One test drive was miraculously silent! I'll reconfirm here after a couple more test drives, but I think I might finally have gotten it. Curiously, no one seems to think these bushings can or will make noise. Thanks for the help.
A month later, it is clear that lubing the trailing arm bushing did the trick. So one of these days they will be replaced.

[moneymanager]

Well I pulled one swing/banana arm. This is the bushing that fell out. I'm pretty sure the source of my noise has been found! Can't wait to see the other side.