My 51 had a nice protective undercoat of 60 plus years of oil/grease/dirt crud that was an inch thick in places. My solution; on a HOT summer day I used a pump-up sprayer and soaked it all with diesel. Next day I attacked the crud with a gasket scraper, screw drivers and whatever else it took to remove the now much softer layer of crud.. This was followed up with a lot of Purple Power (full strength) more elbow grease and a high pressure water hose.
I didn't worry about any consequences, the hot weather soon dried out any moisture. A good grease job add protection where needed.
The huge plus to cleaning things is I found alemites I couldn't see before and the drivetrain upgrades and maintenance work that followed were much easier with a clean undercarrage.
No down sides, just positive results.
Good Luck RonR
