Holden Cruze 2011: Rattling

Like Michael Morris (Carsguide, 17/05/13) we also had rattle in our 2011 Holden Cruze SRI. It was in the rear and sounded like a shocker knock when on unmade roads with corrugations. On a trip to the Flinders Ranges I noticed it stopped when I lightly applied the brakes, so when we got to Broken Hill the dealer there had a look. It was found the rear calipers had too much play in their slides. I thought about taking it up with Holden direct because I believe it's an incorrect manufacturing tolerance. What do you think?