What causes knocking from the front of an Opel Movano over bumps?

Knocking when driving over speed humps and uneven surfaces, accompanied by imprecise steering and uneven tyre wear, is almost always caused by rubber-metal suspension components on the Movano. The anti-roll bar bushes and control-arm bushes wear first. On this model they deteriorate noticeably sooner than the mileage would suggest, especially on vans regularly driven fully laden. Symptoms often appear at only 80,000-120,000 km.

How can I check it before visiting a workshop?

The most effective test is performed over an inspection pit or on a lift. Grip the wheel and rock the front of the vehicle firmly vertically and sideways while watching the mounting points. Play when rocking in the horizontal plane points to the track-rod ends, vertical play indicates the lower ball joint, while a dull knock without detectable play usually comes from the bushes. Replace these parts in pairs on both sides of the axle. If one side is worn, the other has worked under the same conditions and will soon follow. Wheel alignment is essential after replacing track-rod ends or control arms; without it, the new parts can wear out within a few tens of thousands of kilometres. State the vehicle generation when ordering, because Movano A and Movano B suspension parts are not interchangeable.