Dave I feel for you buddy. A long time ago I tried to strip a model RR engine, key word try, with brake
fluid and it stripped the paint fine. It also stripped the bonding agent from the plastic leaving it in the shape of an engine but a rubbery, crumbly mess. That being said, I'd say your problem is the plastic. I now use brake fluid exclusively with no problems. Besides its cheap, a buck at the dollor store, and I can't find purple power around here.