Diagonal braking

?. Forgive me for sounding like a noob but how do they fail internally ? This is a new one to me.

They basically disintegrate from the core of the tubing and cause leaks or clogs. If you have fluid in the system and none is getting to your one rear brake, then it is likely that that branch is clogged. Replace that hose and then bleed the system.

I Googled it after I read it and now I've decided I went and replaced all of them all four lines are being replaced

Replace the two front hoses tried to bleed the front brakes to see if that was a solution still no action on the right front brake no fluid either the hoses dry as a riverbed does anybody have any idea how to test or if I can test the ABS pump unit. Also I cracked the lines from master cylinder to abs pump unit to see if it was the mc. Both reservoirs pumped fluid. Also is there a proportioning valve on the car or is that built into the ABS

Turns out previous owner jerry rigged brakes to avoid replacing front right brake line. I replaced the line. It came out in 4 pcs just by wiggling it. What a pain in the arse. Had to cut and union the line to get it in without dropping the front subframe.