The mystery of the rattle

Technical Area Steering & Suspension
1
  1. My model of MX-5 is: ‘07 NC 1.8
  2. I’m based near: Oxford
  3. I’m looking for technical help or recommendations on: mysterious rattle

Just got back from my decent local garage; took my MX5 to deal with a strange rattle but they couldn’t find any issues. Adds up, because I’ve struggled to find anything. So, I’m here looking for some thoughts from the experts :wink:

Since around February my NC has had a very loud rattle specifically at very low speeds, generally 20mph and less. It sounds like it’s coming from the right rear, but not totally obvious. It has a ‘metal on metal’ quality, I think, but could also be metal on tough plastic. Once I speed up it completely disappears - and not in a ‘I can’t hear it any more’ way, it just seems to smooth out to the point where it doesn’t have the problem.

Naturally it seems like a suspension issue but the garage couldn’t find anything wrong. And given I’ve had this problem since February with no clear major issue with the car, it doesn’t seem to be anything critical. So that’s good. But I’d sure like to get rid of this darn noise!

Any ideas/thoughts would be much appreciated!

Worth noting, it seemed to start not long after I had new front brake callipers, discs, pads + one front drop link replaced. But doesn’t seem to be related… I think.

2

Rattles are often drop links though a competent garage should be able to identify that

3

Is it a dull knock rattle or a buzzy resonant ratlle?

I know this may be a stupid suggestion but is your jack secure and and any tools in the right hand boot compartment?

1 Like
4

I agree with your tool suggestion.
I was in Norfolk this week and had a metal on metal sound from right hand boot area.
After stopping, the issues were the towing eyes and jack handle in the boot compartment.
A quick adjustment and it was sorted :+1:

5

Good questions! It’s a dull knock.

And can confirm it’s not the Jack/tools. I’ve checked that in the past but I even took them out during the drive back from the garage just to double check - still there!

6

Just helped a mate fix a knock/rattle on his NC

We had already done front and rear drop links and had all the bushes closely inspected by the local MOT guy.

Ended up being pad knock.
Once we changed his pads to Mintex - the knock vanished.

He managed to stop the knock/rattle temporarily by very lightly touching the brake without slowing the car down.

2 Likes
7

Now that’s an interesting theory. Given it started after the brakes were changed.

Will give that a shot tomorrow!