Hi I changed the oil today on 1.3 fiesta, with the car on ramps. When negotiating the car ramps, when I stopped halfway up the ramps (for fear of flying off the end of them!) and hit the brakes, I put the handbrake on. However after taking my foot off the brake pedal the car started to roll back down the ramps despite the handbrake on. Is this a potential handbrake failure? Please advise