Originally Posted by the heap

MarkM

Great, if you've found the problem. Until your last post, I would have suspected the track rod bushings. When applying the brakes, the lower control arm is driven backwards into the chassis through the track rod, if the bushing is failing, all of the play is then taken out, and the noise goes away. Release the brakes, drive over a washboard road, and the noise returns. My buddy had similar symptoms on his '83 SD, replacing the track rod bushing solved it.

Perplexed
'77 300D