That "loaner jack that wasn't seated right" line hit me in the gut because I've been there twice this year. We had a 737 with a mystery seep at the wing root and after pulling panels and pressure testing for most of a shift, the whole thing came back to a borrowed jack with a chewed up pad that nicked the O-ring on the way up. Now the rule on my crew is simple: any jack that ain't ours gets wiped down and eyeballed before it goes under a plane, no exceptions. I also mark the pad contact points with a paint pen so I can see right away if the thing is sitting crooked or walked off center. Takes two minutes and it has saved me more than one long night. Six hours on a Tuesday stings but at least you know you ain't the only one who has paid that tax.

Strong disagree on ditching the washer completely. What killed you was the pressure, not the machine. I run mine at 500 to 800 psi with a 40 degree tip, keep it at least a foot off the wall, and never spray upward into the weep screed or around windows. The trick is letting the bleach mix do the work and using the washer just to rinse, not to blast. My place is a 1972 build and the stucco has held up fine since I made that change, so sell it only if you never want to wash anything again.