Volvo Repair: 2000 Volvo S70 Brakes, 2000 volvo s70, vw porsche

Question
I have a customer with a 2000 volvo S70 The customer complained about a spongy brake pedal.  I scanned the vehicle and no faults in the abs or anywhere else.  I have seen this before. I replaced the brake booster and bleed all the brakes.  2 to 3 weeks later customer comes back same problem i replace master cylinder and all seals. Bled brakes and 2 to 3 weeks later same problem.  I know that the left rear brake lines are prone to go bad, but there are no leaks anywhere and none of the calipers are leaking. i really appreciate it thanks.  BMW Mercedes Volvo Service Tech Josh

Answer
   Joshua, since you are a tech. I'll advise this test. Take a brake hose clamp (specialty item, snappy has em) and go around and pinch off the flex hoses one at a time near the steel line until pedal goes firm. Then you know if it's a caliper/hose or not. A vice grip with a rag works, but be careful not to damage hoses.
   My suspicion is you have a bad (internally) front flex line that works in certain turning positions, and not in others. Could be a rear, usually front. Owise, replace master with NEW Genuine Girling and vacuum bleed system. Pressure bleed is ok too but risky/messy if you know what I mean.

    BTW, Audi,VW, Porsche, BMW, Mercedes and Saab are my other specialties. Let me know.

Mark