Propshaft Droning above certain speed

[Mark_B]

At a 'certain speed' (i.e. triple figures) there's a drone from the propshaft, getting louder with speed increase. In a way it's a good as an over speed warning signal. It did it ever since I fitted this replacement prop. When I fitted it the diff input flange was nice and tight to the diff input shaft, all the prop mating surfaces were clean and the bolts had good torque on them. So I think this prop was slightly bent maybe before I fitted it.

An aquaintance of mine in past told me he was balancing a prop by trying a jubilee clip in different positions, but I'm a bit scared to do that now, since he told me that once he was in the middle of listening for the change in sound, when there was a huge bang and the gearbox bearing housing shattered under the unbalance force!

Does anyone know of a good way of balancing it on the car, or know of someone in Herts/Beds area can do it?

[ptjs1]

Mark,

I have no personal experience of these people but have seen their adverts on a number of occasions. Based in Luton, so guess they are close to you?

http://www.reco-prop.com/prop.htm

Many years ago, when money was even tighter than it is now, I balanced a prop on a Triumph Vitesse witha couple of Jubilee Clips. It was very obvious when I got the positions wrong as the vibration kicked in very early and very obviously. I'm surprised that your colleague didn't feel bad vibrations before something went bang.

Good luck

[greeban]

Hi,

Mine does the same - 95+ it begins to drone. I wonder if it is the central bearing?? I have used reco-prop in the past who built a proshaft for my stag and they are very professional.
I am waiting 'till my exhaust falls off and then I will get the shaft out and have it balanced, definately worthwile. I think most older/higher mileage rear drive cars will eventually suffer from this.

[ng4xjs]

Mine too at about 95ish until I replaced the front subframe! The only possible explanation I can come up with is that somehow wheel bearing noise was being transmitted down and along the underneath of the car.


I also had a 3.6 which did exactly the same, never did get to the bottom of it.

Alternatively perhaps it is all......, haven't a clue!

Nick