Author Topic: Help needed with another mystery noise.  (Read 1825 times)

alpina

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Help needed with another mystery noise.
« on: October 07, 2021, 17:38:38 »
I am in need of assistance once again. I now have a new mystery noise.  This only appears when turning left. It seems to be a scrapping sound..
The car has recently passed it’s ITV test here in Spain. (similar to the UK MOT) but a bit more strict. Before this was carried out It went into the garage
to have a pre inspection / check to insure it will pass, this included checking the wheel bearings, which was the first thing that I thought it could be.

The car recently had a brake overhaul, new discs (rotors) and pads, new brake hoses all round. New calipers at the rear (due to brake failure earlier this year..)
While out for a drive today I found that applying the brakes when the noise appears stops the noise. Also if heading towards a left hand turn, I firmly apply the
Brakes before the corner, the noise is then not heard in the turn.
Could this be the caliper not releasing completely ? there is no over heating of the brakes all appears normal.  Working the brakes before a left turn stops the noise
in the left turn. Applying the brakes when the noise appears (turning left) the noise will stop. I have had plenty of practice left braking trying to figure out the issue.
Given the info above what would you suggest I check ?
As always you help is much appreciated.
Cheers,
DM.

Cees Klumper

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Re: Help needed with another mystery noise.
« Reply #1 on: October 08, 2021, 01:22:06 »
Probably not 'it', but could it be something (small stone) stuck between the disc/caliper and the protective backing plate?

Maybe try removing, swapping over (left/right) and re-fitting the brake pads, see if it changes.
Cees Klumper
1969 Mercedes 280 SL automatic
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MikeSimon

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Re: Help needed with another mystery noise.
« Reply #2 on: October 08, 2021, 15:29:05 »
My strategy would be to jack the car up in the front. Either both sides at the same time or one after the other. Have another person sit inside and turn the wheel. While sit at it, you spin the front wheel by hand a see if you can locate and pinpoint the noise. Your assistant in the car can apply the brakes to see what difference it makes.
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Mike Hughes

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Re: Help needed with another mystery noise.
« Reply #3 on: October 08, 2021, 18:07:32 »
I'd be looking for a bit of gravel thrown up into the area around the rotor and caliper or backing plate.  I've encountered something like this more than once over the years, at the dealership where I worked and at car club tech sessions.
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alpina

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Re: Help needed with another mystery noise.
« Reply #4 on: October 11, 2021, 16:26:37 »
Okay an update. I have jacked up front of the car turned the steering and spun the wheels. Nothing can be heard rubbing. Inspected the brake calipers,
Removed and reinserted the pads, checked for trapped gravel and nothing seems out of the ordinary.  All grease fittings greased, no play can be felt
rocking the wheel holding at 12 and 6 and from 9 – 3.
Went for test run today. All was well for around 50km no noise. Then it stated again, not on every left turn,  It could happen on a sweeping left turn or a
Tightening left turn. You can never tell.
I pulled in to a quite area, and drove in left hand circles, I could not make the noise appear. Now the thing I find strange. I parked up for a few minutes
With the engine off. Restarted and headed home, diving the same roads where the noises would appear, this time nothing. It is almost like it had been reset.
I know that does not make any sense but that is where we are.
Is the anything else that could be making noise ? It difficult to pin point the location of the noise, it is more a case of it can be felt though the car.
Noise can happen when coasting or when under power, applying the brakes stop the noise.
Any other ideas ?