Advance preparation for brake bleeding often includes the application of penetrating oil of some type (e.g., Kroil, PB) around the bleeder screw to assist in removal. In some cases, it's applied daily for several days in advance of the bleed operation to allow it to soak in and do its thing.
If penetrating oil really penetrates the screw threads as intended, won't it make its way into the caliper and contaminate the brake fluid? I read somewhere to avoid penetrating oil around brake fittings for this very reason. But I also read many forum posts and watched some videos describing this technique to deal with difficult bleeder screws. Is there any penetrating fluid that will not contaminate brake fluid?
If penetrating oil really penetrates the screw threads as intended, won't it make its way into the caliper and contaminate the brake fluid? I read somewhere to avoid penetrating oil around brake fittings for this very reason. But I also read many forum posts and watched some videos describing this technique to deal with difficult bleeder screws. Is there any penetrating fluid that will not contaminate brake fluid?