Rattling under car

[venomx]

08 Yaris 71000 miles.

 

Recently when going over bumpy roads at over 30mph I hear a fairly loud rattle/knocking sound, from underneath the car 

It's not the plastic undertray, it's also not the heat shield as I've managed to secure them so they don't move.

 

Any ideas?  All I can think is that the exhaust is moving around but I've checked and it seems fine 

[Roy124]

How did you check the exhaust?  If the rear portion is secure it might be the central portion. 

To my mind rattle and knock are two different sounds. The former might be something loose rattling around whereas knock implies something more solid that is colliding with something. 

[Bernard Foy]

Usually a rattling sound is fairly constant, and you seem to have the two main culprits covered. Check the whole length of the exhaust preferably on a lift. Also check track rod ends and suspension bushings for wear..

[alan333]

Previous Avensis' I’ve owned suffered from worn brake caliper slider pins, giving off a rattle when going over rough road surfaces.  Not sure if it would be relevant to your car or not but to test it apply the footbrake lightly when it’s rattling and see if the noise disappears.  

[TonyHSD]

Exhaust heat shield are few and also there might be one attached to the exhaust manifold, have you checked that one too? You have to lay underneath and touch everything to find it. 👍

[venomx]

3 hours ago, alan333 said:

Previous Avensis' I’ve owned suffered from worn brake caliper slider pins, giving off a rattle when going over rough road surfaces.  Not sure if it would be relevant to your car or not but to test it apply the footbrake lightly when it’s rattling and see if the noise disappears.  

Seems this is the case.

Took it for a drive, was rattling around lots, applied the brake lightly and it stopped. Did this a few times too, every time i'd apply the brake it would go silent.

When I go to the mechanic should I ask them just to replace the slider pins ? As the pads and discs are new. 

Thanks

[Cyker]

May also be the brake heat shields - They tend to be rusted to smeg by this point on a Yaris! They usually make a nasty screeching noise at certain steering angles tho', rarer for them to just rattle.

 

[venomx]

I'll take it to the mechanic and let them look.

Its likely to be the brakes as it stops as soon as I apply them

[TonyHSD]

2 hours ago, venomx said:

Seems this is the case.

Took it for a drive, was rattling around lots, applied the brake lightly and it stopped. Did this a few times too, every time i'd apply the brake it would go silent.

When I go to the mechanic should I ask them just to replace the slider pins ? As the pads and discs are new. 

Thanks

These slider pins may also have rubber inserts on them and many mechanics remove these because often they are swollen and pins can’t go back in., or if the grease has dried out and they are left bare metal inside. Best to get it check again. 👍

[alan333]

15 hours ago, venomx said:

Seems this is the case.

Took it for a drive, was rattling around lots, applied the brake lightly and it stopped. Did this a few times too, every time i'd apply the brake it would go silent.

When I go to the mechanic should I ask them just to replace the slider pins ? As the pads and discs are new. 

Thanks

I replaced the pins on one of my rattly cars, but on another I stripped them and packed them with grease, which kept the noise at bay for a while (although it did come back).  Best to see what your mechanic says and take it from there.

[venomx]

39 minutes ago, alan333 said:

I replaced the pins on one of my rattly cars, but on another I stripped them and packed them with grease, which kept the noise at bay for a while (although it did come back).  Best to see what your mechanic says and take it from there.

Thanks for the info. Helps massively now I can narrow it down to the brakes. Booked in with the mechanic, hopefully they can sort it out 🙂 

[Bernard Foy]

2 hours ago, venomx said:

Thanks for the info. Helps massively now I can narrow it down to the brakes. Booked in with the mechanic, hopefully they can sort it out 🙂 

Let us know what your outcome is Terry.

[alan333]

4 hours ago, venomx said:

Thanks for the info. Helps massively now I can narrow it down to the brakes. Booked in with the mechanic, hopefully they can sort it out 🙂 

You’re very welcome 🙂. 

[venomx]

On 3/24/2022 at 12:20 PM, Bernard Foy said:

Let us know what your outcome is Terry.

Thanks. Will do 

[venomx]

Does sound like a bolt is rattling around, sometimes it's quite loud.

I have checked the calipers, discs and pads ( quick inspection without taking anything off ) and there's no movement at all.

I'm booked in with the mechanic this friday so hopefully they can fix it. I'll stick to local necessary journeys until then.

[venomx]

Took the car down yesterday  and they said the front bottom ball join has play, so so replaced the front lower arm.

Arm pin and bush was replaced 5 months ago.

 

It is still making the noise so not happy I just spent about £140 for that.

 

I'll be taking it back down this week 

[TonyHSD]

1 hour ago, venomx said:

Took the car down yesterday  and they said the front bottom ball join has play, so so replaced the front lower arm.

Arm pin and bush was replaced 5 months ago.

 

It is still making the noise so not happy I just spent about £140 for that.

 

I'll be taking it back down this week 

Rattling noises can also come from the brake pads themselves, if you had replaced them recently have you installed all metal shims correctly? Sometimes non oem pads can have slightly smaller sizes and not seat properly into their places but that should be covered by the shims, maybe another look around the brakes but it will need to be wheels off the car and pads taken out, all cleaned and put back together. Also the slider pins checked. If you do it yourself it’s ok ish to look for things like that but when going to a garages they will always try to find something to replace to earn money out of you without care if they really found and and fixed the problem. 

[Bernard Foy]

2 hours ago, venomx said:

Took the car down yesterday  and they said the front bottom ball join has play, so so replaced the front lower arm.

Arm pin and bush was replaced 5 months ago.

 

It is still making the noise so not happy I just spent about £140 for that.

 

I'll be taking it back down this week 

If you remember my first post Terry, I did mention suspension bushes and track rod ends, because I was looking at the cars age and mileage. But he’s not cured your rattle.

[venomx]

1 hour ago, Bernard Foy said:

If you remember my first post Terry, I did mention suspension bushes and track rod ends, because I was looking at the cars age and mileage. But he’s not cured your rattle.

The mechanics are friendly so hopefully they can have another look. It's not so much the rattle but that something in the brakes must be loose and could be hazardous.. As as soon as I apply the brake even lightly it disappears.

[alan333]

On 3/28/2022 at 4:48 PM, venomx said:

Does sound like a bolt is rattling around, sometimes it's quite loud.

I have checked the calipers, discs and pads ( quick inspection without taking anything off ) and there's no movement at all.

I'm booked in with the mechanic this friday so hopefully they can fix it. I'll stick to local necessary journeys until then.

My money is still on caliper slider pins. It’s been a while but IIRC you hold the caliper firmly in the 9 and 3 o'clock positions and try to move in/out, pushing one hand while pulling the other.

[venomx]

Right. Had a look today at it seems as though the " stone shield " behind the disc was rattling around and making contact with it. Moved it away gently and now it seems to have disappeared. Will keep an eye on it

[alan333]

17 minutes ago, venomx said:

Right. Had a look today at it seems as though the " stone shield " behind the disc was rattling around and making contact with it. Moved it away gently and now it seems to have disappeared. Will keep an eye on it

That's a good result, and cheaper than my suggestion.  Hopefully you're all good now 🙂

[venomx]

Noise is quieter but still there.

I'll go back to the mechanic and see if they can help.

 

Thanks anyway !

[Bernard Foy]

Hopefully you’ve got the source of the rattle 👏

[venomx]

Back to the mechanic next week.

@alan333

I believe it is the slider pins too. Quick question, why does applying the brake lightly get rid of the rattle completely ? Is it because when the pad touches the disc it stops any movement ?