I need to replace cracking rubber brake lines. I plan on having all the hard lines and fittings on hand and replacing those as well. I will do all the pre-loosening procedures PB,heating/cooling,tapping,and the prayer. While apart are ther any things i should just replace,ie proportioning valves, MC, any seals etc. 120k on the car and no leakage or other symptoms, i like to take the preventative approach, while everything is apart. Thanks Bob.