Global driver,
As I (in Euro land) understand how this works.
During normal ops before departure or in flight you have to factor so ldr*1,67 if dry or ldr*1,92 when wet (I'm not getting involved in grooved or not at this time, different discusion). if prior to departure you have another issue (your brake example) you will have to add that factor.
So in your example, multiply the initial result by 1,55.
If this happens in flight (I'm not getting into discussion when a flight starts, is that off-blocks or airborne). And the failure effects the performance of the airplane (which it does in your example). you can disregard the initial factoring and be legal (but maybe not smart...) with just ldr*1,55.
What I have been doing is: I do not accept anything less than the initial (before departure) requirement.
Unless in an emergency than all of this goes out of the window.
As I said before this is how I understand it works, I do not have a readily available reference.
GC