A most peculiar noise

[Nickol]

I know that of course "noises" cannot be efectively diagnosed in a written forum and taking a picture of a noise is even more difficult, however.....

In normal driving of my 69 Traveller I hear a sort of intermiitant rubbing noise coming from the underside , possible near to and around the gearbox. I can only describe it as the sort of rubbing noise you might get if a single brake liner is rubbing. The noise is most definately not the brakes as the tempo of the rubbing nosie I hear is much too slow to the speed of the car.

I thought perhaps the propshaft but again , this rotates at approx 4 times the speed of the turning wheels and my noise is maybe only a third or less than the turning wheels.

What could it be?

[geoberni]

Now here's a puzzle.....

What sort of rubbing noise would you describe it like, is it harsh and metallic, or perhaps more gentle like there is something in between the surfaces, you did say like a 'brake liner', but I always think those are more of a 'squeak' or 'squeal'...
Does it sound like it's rotational, or more of a back and forth, I'm wondering if it might be a gearbox mounting, although I'd have expected the Tuv tester to have found anything serious....

[Monty-4]

Hmmmmmm!

Check the front shock absorber mounting bolts, the gearbox end of speedo cable, the gearbox mounts... and your leather shoes?

[Nickol]

Now here's a puzzle.....

What sort of rubbing noise would you describe it like, is it harsh and metallic, or perhaps more gentle like there is something in between the surfaces, you did say like a 'brake liner', but I always think those are more of a 'squeak' or 'squeal'...
Does it sound like it's rotational, or more of a back and forth, I'm wondering if it might be a gearbox mounting, although I'd have expected the Tuv tester to have found anything serious....

It is more gentle as you say ( can a noise be gentle?? - but I understand what you mean) No squeak or squeel more of a "zoof.....zoof.....zoof" in a regular rythm. Now I think about it, I must try to drive at about 50 or 60kmh and

1. Press the clutch down and see what happens.
2. Select neutral and then
3. Turn engine off as well

As for the gearboy mounting - everything underneath is so clean you can easily see all the mountings as they are not covered in underseal or wax oil. Thus anything loose would be instantly recognised.

I have recently had to replace the clutch pedal as the shaft had broken off from the pedal itself and need re welding - which as is the norm with me, had to do it twice because the shaft was set at the wrong angle. Cannot think of anything rotating there though.

[geoberni]

If it's a regular rhythm, then its almost certainly something rotating; many things like springs, shocks etc depend on the road surface for their operation, so that affects the noise.

[kevin s]

Does the frequency change as you go round corners? wondering if it could be the differential.

[Nickol]

Does the frequency change as you go round corners? wondering if it could be the differential.

that is a thought - I will check next time on the road.

[Nickol]

UPdate.

The rotational noise. It disappears when the clutch pedal is pressed.

Thus my conclusion is, it emanates from the thrust bearing.

[svenedin]

Sounds gearbox related. First motion shaft?

[Nickol]

Sounds gearbox related. First motion shaft?

first motion shaft = layshaft?? I thought about that as well - But then I would not expect to hear anything in 4th gear.

[paul 300358]

Check that your fan belt is not over tight and that the pulleys are properly in line.

[kevin s]

Is that when you fully press the pedal and disengage the drive or just a light pressure on the pedal.

[Edward1949]

UPdate.

The rotational noise. It disappears when the clutch pedal is pressed.

Thus my conclusion is, it emanates from the thrust bearing.

Remember that the Minor clutch is released by mechanical means. This means that the whole engine/transmission is displaced slightly when the pedal is depressed. This can introduce a whole array of subtle changes in baffling noises which may be unrelated to the clutch itself.

[Nickol]

UPdate.

The rotational noise. It disappears when the clutch pedal is pressed.

Thus my conclusion is, it emanates from the thrust bearing.

Remember that the Minor clutch is released by mechanical means. This means that the whole engine/transmission is displaced slightly when the pedal is depressed. This can introduce a whole array of subtle changes in baffling noises which may be unrelated to the clutch itself.

Very good point - thankyou. I will put my thinking cap on.

[Nickol]

Is that when you fully press the pedal and disengage the drive or just a light pressure on the pedal.

It is when I fully press the clutch pedal down. I did this experiment downhill. The rotational noise does not seem to be there when I press the accelerator.