ratlly/vibration noise

[justforfun]

Hi. I have a kiwi 1990 1.6 NA with about 190,000 k's on it. It has developed a rattly/vibration noise in the rear end that is noticeable when you decelerate especially in 3rd or 4th and when the car has warmed up. Sounds like a diff possibly but not sure. Any idea's? Also can someone tell me what type of diff it might have in it if I was to replace it? Thanks

[Mr. Shine]

Rear muffler heat shield?

[SLYDIT]

welcome to the world of the MX5 rattle!
it is totally normal and totally frustrating.
there are two main causes.
1) the heat sheild on the extractors can break a bracket off causing the heatsheild to rattle.

2) and the most likely cause, is a harmonic in the drive train that causes that awful noise.
You can change your gearbox or your diff (or both) and there is no guarantee that it will go away.My car is on its 3rd gearbox and it still does it.

its just one of those annoying things..theres a guy on miata.net who had both his gerabox and diff fully rebuilt at the cost of $$$$$$ and his car STILL did it.

just turn the stereo up more!

[Angreal]

Or get a noisier exhaust... I've noticed that ever since removing the cat on my car I can't hear any rattles/squeaks when topless

[brownie]

driveshaft universals maybe

[Kieran]

1. Poly Exhaust Bushings
mines making a rattle near the back but I figured out it was the exhaust rattling at certain rpm

2. Headers Heatshield
Take it off get a heatshield for the intake

3. Poly Diff Bushings
Energy Bushings makes these

4. PPF Brace
Beatrush makes this as does Carbing and Cusco

If none of this works don't pursue any further it will cost you more money than a little rattle is worth

[Angreal]

4. PPF Brace
Beatrush makes this as does Carbing and Cusco

If none of this works don't pursue any further it will cost you more money than a little rattle is worth

Has anyone done this option 4 before?

[MN]

OK here is another one that developed on my car yesterday just out of Levin.

A loud graunchy rattle from the left front that disappeared at about 40 kph and faster and when the brake is applied? Really noisey driving through Wellington to get home. The car braked and drove in a straight line, no pulling to the left. I thought it may be a wheel bearing but the hub was cold when I got home, no wobble in the wheel and no stone that I could see. It isn't worn pads either.

Any ideas?

[Mr. Shine]

Wouldn't expect a stone unless it was a really graunchy whine/screech/scrape sound. Could be worth taking the discs off to check there's nothing between disc and dust shield, I had one there a while ago. Took care of it on the side of the road in about 15 minutes with odds and ends that were left from the 23 year-old factory-supplied toolkit

[brownie]

anti rattle clips possibly fallen out,pads rattling around until you put the brakes on.
First thing to check anyway,and make sure all the caliper bolts are tight !

[MN]

Thanks for the ideas. I pulled everything apart and there is no strange wear patterns, no shiny bits indicting rubbing, all the bolts were tight and the road test afterwards there was no noise what so ever - one of those motoring mysteries I suppose.

[justforfun]

hi thanks for the replies re this problem. Sorry about my ignorance but what is a ppf brace please?

[justforfun]

Hi thanks for the replies and Info. Excuse my ignorance but what is a PPF Brace please? Sorry. Please ignore this one, PC Playing up hence the double up.