Rumbling Noise 55-65mph

[Robho]

I've separated this from my prior thread (Unusual Braking Problem) since, after further investigation, it is likely unrelated. I've included some of that background, where it may be relevant to this problem.

2006 1.6HDi Combi. (with ABS)


A couple of weeks ago, I experienced an unusual vibration through the steering, as if a front wheel had lost a balance weight....but very oddly, 'coming and going' ...for want of a better description, at 50mph "on" for 3 seconds and "off" for 3 seconds, repeating. I was half a mile from home so decided to continue steadily down the quiet rural road. When stopped, I could smell brake material and, sure enough, the nsf this time was hot. Let it cool down, lifted the front and the brake was virtually seized. Due to needing the vehicle, the calliper was swiftly replaced and the seized one given in p/ex. With hindsight, I wash I'd stripped it first - it is unknown whether a calliper fault was the problem or the seizure was caused by the calliper overheating due to another issue.


Since then, I noticed an intermittent, subtle but definite vibration, seemingly from the front of the vehicle. Similar to driving along and the road surface changes to a more uneven one. Can't detect a pattern, but does seem (slightly) greater at c 50mph. 

On checking the car yesterday, the wheel bolts were all tight. When the vehicle front was lifted, I noticed the nsf wheel is dragging compared to the offside front. Whilst not scientific, to illustrate the difference, approximately the same force exerted to spin the wheels one at a time results in the offside front doing 3-4 revolutions, the nearside barely one revolution.

Further investigation today:
- removed the nsf wheel
- visual inspection of the wheel/tyre/suspension/brake reveals nothing visually untoward
- decided to swap nsf and nsr rear wheels/tyres 'just in case'..

On test drive today:
- all fine up to c. 50mph
- around 55mph a rumbling noise can be heard
- it is subtle but can be felt through the body, more than the steering wheel
- in terms of location, difficult to say but appears to be coming from between the driver's left foot area and the nsf of the vehicle
- noise continues, but gets no louder (same for vibration) up to c 65mph, then dies away again
- is related to road speed rather than engine speed (i.e. changing gear/selecting neutral/dipping clutch pedal makes no difference)
- is repeatable at the above road speeds
- no vibration on braking (brakes working normally)
- steering doesn't feel any different


Appreciate any helpful thoughts,

[evdama]

Wheel bearings?
They dont have to be slack to be noisy.

[Robho]

Thanks. Wheel bearings on both sides were replaced c. 7k miles/15 months ago.
And, for completeness, I couldn't feel and excess movement when car was jacked up (and, whilst not conclusive, just had an MoT test too, which showed nothing awry).

[Guanock]

An MOT test will not normally identify a noisy wheel bearing.

Geoff

[Robho]

I commented about the MoT since the test does check the suspension (etc.) for excessive play/wear.

Although, in this particular case, prior, the MoT tester did point out a noisy bearing - hence having them replaced. I appreciate its not part of the test as such of course.

[jj9]

Put your fingers on the coil spring when you spin the wheel, you can normally feel any roughness in a bearing, compare sides to see if there is any difference.

[evdama]

And you will need the pads out to ascertain for sure rather than putting absolute faith in a third party telling you the work has been done.

[Robho]

Put your fingers on the coil spring when you spin the wheel, you can normally feel any roughness in a bearing, compare sides to see if there is any difference.

Good suggestion. thanks.

[Robho]

And you will need the pads out to ascertain for sure rather than putting absolute faith in a third party telling you the work has been done.

Trusted mechanic, done at my house with me present (but I understand the point).

[smutts]

How hot did the brake disc get?

I remember years ago passing a car on a dual carriageway at night,
Surrounded by a glow,
bit like Dean Stanton's car in the film "Repo Man"
except orange instead of bluey green.
Definitely had a (VERY!) dragging front disc.

If yours got pretty hot, then there might be bearing issues.