I need help with an unknown squeal.
1995 bmw 540i with 6 speed manual
Squeal starts from about 20mph and changes slightly as speed goes up.
Will happen while coasting in neutral, so it is drive dependent .Tried revving the car parked and while coasting and can never get it to squeal.
Swapped all pads and rotors this weekend. Squeal was there BEFORE brake work. That was one of the reasons why I did it, thought it was brake related.
I can not pinpoint the sound. Thought it was a wheel bearing but I can’t hear it any louder on one particular side. And it doesn’t change while taking hard or soft turns.
I am pretty sure these cars have a 2 piece driveshaft so a failing driveshaft center bearing would be my guess.
Thanks for the advice. I had no idea. I’ll definitely check into that.
Another idea, I get sort of a chirping sound from the truck’s driveshaft if the u-joints are getting dry. It isn’t a constant squeal sound though, more like a repetitive bird chirp.
One thing I do when diagnosing this btw is listen to the sound with the windows open on both sides of the truck, listen to the chirp as I’m passing other cars. Sometimes the way the sound wave from the driveshaft reflects off the adjacent car and changes how it sounds to the driver can provide a clue. Works best if the adjacent car is a behemoth monstrosity, a 12 passenger van, huge suv, bus etc.
Thanks for the advice. I’ve tried driving by buildings in close quarters to see if I can hear the sound. I’ve had my son stand outside as I drive by to see if he can at least pinpoint a side. Seems like it’s coming from under the car as the sound is equally loud on both sides. I’m going to try again before I rip out the exhaust to check the carrier bearing. I did a visual and the bearing looks clean with no grime or dirt on it. I grabbed the drive shaft and it had very little play inside the bearing. So I want to be 100% sure it’s not a wheel bearing or sticking caliper.