I just replaced all 4 hoses on my rear CTIS (M931A2). My local Parker outlet had exact replacement hose in stock, not too expensive:
- Parker 293-6 Airbrake Hose
- Braided
- 8mm (5/16")
- SAE J1402
- 500psi
Have fun cutting it, it has a thin metal braided layer underneath the outer braided nylon layer (so did the original hoses I replaced). I used a metal cut-off blade, nice clean cuts all the way through.
When removing the old hoses from the metal ends, after you remove the outer lock nut, the inner insert (the metal threaded tube that goes on the inside of the hose end) has reverse threads, so turn opposite to remove the hose. Once I broke mine loose, I used my hands to unwind them from the insert tubes.
HTH, good luck.