humming brakes

Endoman · 23 Jun 2018

9xxnick said:
9xxnick said:

Have your wheels been refurbished/repainted?

Click to expand...

OP - this may not seem relevant, but trust me that it may be if your wheels have been repainted.

If paint has got onto the face of the wheel where it mates with the disk, this causes the clamping force of the nuts to be uneven across the disk's bell. When it heats up this allows the disk to distort - temporarily at first, then permanently as the "high points" get worn down. New disks will cure the problem temporarily (few hundred to a thousand miles, dependent on brake use) and it will then recur.

This is by no means the only mechanism that can cause brake vibration, but it is absolutely and demonstrably one possible cause.

The wheel nuts also come loose on repainted wheels, the paint in the nut seating area will crack or soften. A Lotus Elise almost lost a wheel at an Oulton track day for that very reason.

9xxnick · 23 Jun 2018

Indeed. The mating face of the wheel should be bare metal.

spannermonkey · 24 Jun 2018

wheels were refurbed several years ago. I actually suffered from the dreaded loose wheel nut saga, first run out. Scared the hell out of me. A wire brush and a re-torque sorted it.
Im now focusing on two areas. Front wishbone bushes for the slight shimmy at 55mph and the rear discs for the rumble. Had a mate get in the back and he reckoned the noise was coming from the rear axle under braking.

9xxnick · 25 Jun 2018

Well, best of luck with sorting the issues out. The front wheel shimmy when not under braking could easily be the wishbone bushes. These should be very apparent if you lever the wishbone against the mounting.

If this is the case, I would also expect to see some degree of uneven wear across the front tyres due the wishbone allowing them to toe out under braking. This would cause more wear on the inside of the tyres compared to the outside.

humming brakes

Endoman

Albert Park

9xxnick

Spa-Francorchamps

spannermonkey

Monza

9xxnick

Spa-Francorchamps

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