Replacing the D4 lower collapsible steering shaft

Dave Barker demonstrates a common cure for sticky and heavy steering

Common cure for heavy, sticky steering

THIS Discovery 4 TDV6 (with stop/ start system) had covered 96,000 miles and was suffering from heavy steering to the extent that it was becoming difficult to turn the steering wheel, and would often not automatically return to its centre position.

The Discovery’s steering system comprises two main parts – the steering wheel column assembly and the hydraulic-assisted steering rack. The column assembly is basically three sections: the upper column unit which carries the steering wheel and, below that, an intermediate shaft and a lower collapsible shaft connecting to the steering rack.

The steering on this Discovery 4 was checked over and a partially seized lower steering shaft universal joint at the bottom of this shaft, which connects it to the power steering rack, was suspected as the cause of the stiff steering. The universal joint is very exposed to the elements and so corrosion here is common.

On early Discovery 4 and all Discovery 3 models it’s possible to see and feel this lower shaft to inspect it. However, on this Discovery 4 the control module for the engine stop/start feature is located in the engine bay and makes access to the upper part of the lower shaft difficult. The only way to check the shaft is from under the vehicle after removing the engine undertray.

The shaft’s U/J is not a serviceable item, so the complete lower collapsible shaft needs to be replaced, which isn’t a difficult job once you’ve gained access. The shaft is held by a single bolt onto the intermediate shaft at the top, and a single bolt at the bottom where the U/J slides onto the input shaft of the steering rack. With both bolts removed, the top of the lower shaft will slide down off the intermediate shaft, and then the UJ at the bottom of the shaft slides up off the input shaft of the steering rack for the shaft to be removed from the vehicle.

Where engine stop/start is fitted, to access the top securing bolt holding the lower shaft to the intermediate shaft, the stop/start system module needs to be moved clear. This requires several multi-plugs to be disconnected and some trim sections to be taken off and several wiring multi-plugs to be disconnected before the module can be moved to give access to the bolt. One important point to remember – do not rotate the steering wheel once the steering column has been loosened and removed. To ensure the steering wheel is not moved and it remains in the straight ahead position, we locked the steering wheel by using the steering lock. The main battery earth should be disconnected before starting work.