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drum brakes grinding when cold
dave dickson - 19/2/06 at 08:03 PM

on the 406 estate, the rear passenger side drum has started making a bad grinding noise when braking for the first few pushes when cold.
Its definately the rear brakes as it makes the same noise if i pull the handbrake. The grinding fades away as the brakes warm up with use.

I assumed the shoes would be worn or unseated, so got a new set and had the drum off today. The old shoes still have plenty of life in them, are worn evenly and all seems well. They are seated properly and free to move as required. There is no sign of metal-metal rubbing anywhere

Anyone got any suggestions for a cure? Its a really bad noise, and has only started doing this recently. Its got me a bit worried as "something" is definately amiss, but I just cant see what.

Mansfield - 19/2/06 at 08:46 PM

Mine (406 Saloon) does the same. Only after it rains during the night.

I was concerened, but it goes after a few applications of the brake. And each time it rains, the same happens again.

I am no longer concered.

dave dickson - 19/2/06 at 08:48 PM

ah well, I will just live with it!

Thanks.

gazza285 - 19/2/06 at 09:04 PM

Turn the radio up.

mark chandler - 19/2/06 at 09:42 PM

Try grinding a bevel on the leading edge of the friction material, stops the shoe chattering.

Regards Mark

RazMan - 19/2/06 at 10:58 PM

quote:
Originally posted by mark chandler
Try grinding a bevel on the leading edge of the friction material, stops the shoe chattering.

Regards Mark


That gets my vote too - I used to do this to my old BSA A10's twin leading shoe brake .......... god I feel old

dave dickson - 19/2/06 at 11:07 PM

i have done that in the past on other things and its worked - it also helps stop squeel from front pads of you bevel all edges of the pad slightly...
but the old shoes on the car already had a chamfer on them.

JAG - 20/2/06 at 08:58 AM

When cold or wet friction materials can exhibit some strange effects. It can be related to moisture in the atmosphere. The material will absorb this moisture and the friction levels will go up - this changes the way the friction material and drum interface works and can generate squeaks, squeals, grinding noises etc...

It used to be called 'morning sharpness' mostly because morning dew would cause it to happen overnight and the first few brake applications, next morning, would cause these strange noises. As you have noted it goes away once warm because the friction material drys off and returns to its usual friction levels.