Nasty Noise

[seveer unaek]

Ok guys and gals... need your advice!

Iv got a nasty grinding/knocking noise coming from the rear of my car.

It only occurs when there are two people in the back and the car is moving, usually at slower speeds and when going over bumpy roads.

It sound metallic more than anything, which means It's doubtfull the wheels are scrubbing.

It could be the exhaust hitting somewhere but iv checked it all with a fully laden car being bounced around and it doesn't seem to catch anywhere.

Iv checked the springs and there are no cracks or creaks when I bounce it about. The shocks are fine too (no boingy-boingy and no leaks).

I have no idea what it could be so any help is nice! I was thinking that It could be the drums getting knackered or the boot lock etc but the noises would occur all the time then... this is only with people in the rear. It's very confusing!!

[armoredfist2002]

I doubt it is your exhaust, as that sit's up and away as not to catch,

I get a similar noise, I don't know if it's the bottom of the sills, or the little black pieces at the back of the sills at the rear of the car (if you have these on your car).

Not much else hangs down from under the car

[viperroom_112]

My friend's astra does exactly the same thing ! when goin over uneven road surfaces , it is very annoying ! but it appeared to be the mudguards catching on something so I aint to sure ...

Hope u get it sorted

david

[seveer unaek]

Could be the mud-guards but the exhaust sits lower than that (a section of piping anyway) I think it could be the backbox catching on the rear bumber... may have to bend it or cut it a bit... it's annoying though!

In an ideal world I would have no rear seats at all... no passengers then and no noise then! But, unfortunatley, i am the nominated driver most of the time.

Need a second car!

[blue-baby]

Could be the chassis hitting the top part of the exhaust.,were it bends over the axle?

[Bee]

Is your Yaris equipped with a mechanical Load-Sensitive Proportioning Valve (LSPV) or an Electronic Brake force Distribution (EBD)? Models from May, 2003, have ABS and the EBD replacing the LSPV. If your Yaris has the LSPV (since yours is of ?2002 vintage, it looks like you have), then this may well be the culprit.

The LSPV on the rear axle (Lt. of centre) is sensitive to load. A spring between the car body and the rear axle in normal operation collapses in proportion to the load at the back. This in turn operates on a valve which apportions an appropriate front-to-back braking pressure to the rear brake drums. It is quite possible that the spring has snapped, thus the bottom of the car body is almost touching the normally up-and-down moving rear axle. This is then the source of the knocking noise whenever there are passengers at the back and whenever the car is running on bumpy roads.

The Haynes Manual has a short section on LSPV but is woefully inadequate. However, it says that any problem here requires a Toyota dealer's or a specialist's investigation.

--

Bee.

[seveer unaek]

Is your Yaris equipped with a mechanical Load-Sensitive Proportioning Valve (LSPV) or an Electronic Brake force Distribution (EBD)? Models from May, 2003, have ABS and the EBD replacing the LSPV. If your Yaris has the LSPV (since yours is of ?2002 vintage, it looks like you have), then this may well be the culprit.

The LSPV on the rear axle (Lt. of centre) is sensitive to load. A spring between the car body and the rear axle in normal operation collapses in proportion to the load at the back. This in turn operates on a valve which apportions an appropriate front-to-back braking pressure to the rear brake drums. It is quite possible that the spring has snapped, thus the bottom of the car body is almost touching the normally up-and-down moving rear axle. This is then the source of the knocking noise whenever there are passengers at the back and whenever the car is running on bumpy roads.

The Haynes Manual has a short section on LSPV but is woefully inadequate. However, it says that any problem here requires a Toyota dealer's or a specialist's investigation.

--

Bee.

Cheers a lot for that... does sound quite likely!

I'll look into... or get my trusty mechanic to!