Many of us, myself included, know that the rubber flex hoses can fail internally and cause problems with brake calipers failing to fully retract, and clutch engagement becoming wonky. This month the feel of the clutch pedal on our 86 Spider began to feel weird. The pedal was not returning as quickly as I was raising my foot. The problem was the hose; no surprise. What was surprising, was that the hose was just 25 months old (purchased and installed 25 months ago). It was replaced with a new master and slave cylinder at the same time. About 1500 miles driven in those 25 months. The fluid was clear, and other than the slow retracting pedal, everything was in order. FYI, I have been using Valvoline DOT4 "Synthetic" brake fluid for decades in this and dozens of other cars with no similar problems. The new parts were purchased (25 months ago) at either Difatta, or Centerline. The hose is Pirelli stamped with other numbers, etc. In the image below, you see how I cut open the hose to reveal the inner hose that carries the fluid. The rubber on the inner hose had become VERY gummy; I could easily scrape the gummy rubber away from the ID with my finger nail. Very disappointing. I replaced the defective hose with the stainless steel braided "upgraded" (I hope!) hose that Centerline offers. Now, the clutch pedal feels great again.