I have an '05 XKR and often hear a knocking sound coming from the bulkhead area (behind dash fascia) as I go over bumps. The dealer pulled up an old tech bulletin (#910-05) that outlines removing the nuts & screws from the two bulkhead braces and using new nuts/bolts and Loctite. The braces run from the strut tower to the bulkead. They want a rediculous amount for what the TSB shows is a .6 hour job. Has anyone performed this? It looks like I have to remove the wiper blades and plastic cowl to get the torx bolts on the bulkhead.

 

Forgot to mention that the car only has 13k miles...

 

Removing the wipers and plastic trim is really not a difficult job as I have tried it. You need a $10 wiper puller thingee. My bolts were very tight but I still have a knocking under the dash on small bumps, not large ones. There is also a history of duct work separating and causing this symptom.

I had almost rather pull the engine before the dash.

 

Thanks for tip. I'm not convinced this is the source of the problem but will try it since it is not a big job. The TSB describes this as a solution to a "squeak/rattle" complaint rather than a knock. Odd that it doesn't do it all the time; less so in the morning when cold and more as the car gets warm and 'loose'. It's too bad, it is an otherwise very tight car for a 5 year old convertible.