Technical Loud knocking from rear, help!

[NickK]

Hi Guys,

I'm new to the forum, happy new year!

I've recently purchased a Fiat Ducato LWB hi-top 2001, everything's been great apart for this one problem which has been getting worse.

When I used to turn left I'd hear a loud knocking coming from the back of the van (it could only be heard by passengers in the back) although now it seems I hear this knocking sound when ever I accelerate. When accelerating the knocking seems to be faster to match the vans speed.

I'm pretty sure this isn't a misformed tyre as I'd imagine at 70MPH you'd really feel it through the steering.

I'm don't know a lot about the ducato's and have been a Transit man up until this point although can see it's front wheel drive which means I can rule out the problem of it being anything to do with the prop shaft?

From the best of my research it looks like this could be either the rear suspension or some type of joint (cv/bearing?) although the suspension has recently been replaced by the previous owner (has covered about 2k miles since).

The steering is spot on and does not wander or do anything abnormal.

Any ideas where I should start looking?

Thanks for your help!

 

[cris1117]

Hi.
There isn’t much to go wrong on the back end.
The most obvious and quite often ignored is the wheel nuts; they can work loose but are never checked.
Check the exhaust mountings are O.K if one has broke the exhaust can knock against the underside especially on bends when the van leans over.
The rear wheel bearings usually just whine until they drive you nuts and you get them changed.

 

[NickK]

I just thought I'd reply to this for the benefit of other users.

It turned out that the noise was coming from the banging of the metal brackets that hold on the spare tyre. They were just hanging there banging against the bottom of the van as there is currently no spare tyre in place.

Thanks for your reply.