It leaves Pontypool as last of the 16 clubs after a disastrous run that has seen them lose 11 and draw one of their 12 matches since October 25.
Half-backs Byron Hayward and Bryan Shelbourne and No 8 Manu Tuipulotu had too much experience for Cardiff, yet after taking a 17-0 lead, they fell away in the final three minutes of the first half, plus eight minutes of injury time and Cardiff replied with 17 points.
Wing Len Woodard’s first try on his return from Aberavon, via a spell at Pontypool, plus a penalty try took Vale away again and a last-minute try by Elgan Jones failed to save Cardiff.
