North Wales Jag Centre shows how to remove and replace the front subframe on an X350-generation of the Jaguar XJ
WORDS & PHOTOGRAPHY ROB HAWKINS
THE X350-generation of the XJ6 and XJ8 may have an aluminium body, so rotten sills and arches are no longer a problem, but sadly, its steel subframes can still corrode. We’re following North Wales Jag Centre replacing a front subframe, which is rusty, but more worryingly, has broken engine mounting points. The part of the subframe where the engine mounts are fitted has broken away on the 2007 vehicle seen in our photographs, so the best solution is to fit a replacement subframe.
Another problem with these subframes on the XJ X350 concerns undoing the mounting bolts. These are threaded into captive nuts, which can break off. If this happens, the frontmost bolts can be accessed by removing the headlights and bumper, whereas the rears are more of a challenge and may require the front suspension air bags to be removed to access the captive nuts – Matt Norbury at NWJC warns that he’s often had to apply lots of heat to remove these nuts.
And problems can emerge even before you get to those subframe mounting bolts. Matt says the fastenings for the engine undertray and the ones for the front bumper can seize, so it’s often easier to remove the front bumper with these two undertrays attached.
The job begins by fitting an engine support beam across the front wings and attaching it to two points on the engine. This will hold the engine when the subframe is removed. Next, the road wheels are removed The engine undertray is removed, secured with 10mm and Torx T25 fastenings, followed by the front bumper’s undertray, which is fitted with 10mm and Torx T27 fittings The steering rack is attached to the subframe, but will remain on the vehicle, so technician Paul at NWJC undoes the 19mm nuts on the trackrod ends, followed by two 18mm mounting bolts for the rack There’s one more 18mm bolt to undo, near where the column fits to the steering rack (it’s supported with a transmission jack), then the rack is pulled away and suspended with cable ties and bungees There are more components attached to the subframe that need detaching, such as this mounting bracket for a power steering pipe and the clamps for the height sensors, attached to the lower suspension arms Paul cleans the threads of the suspension a
