Hello: I have been trying to get good replacemnet Carrera chain tensioners. The pressure feed ones. I have ordered 3 tensioners from 2 different suppliers. All are bad and won't pump up. Has anyone else had this problem recently? I have been installing these in cars for 18 years and these are the first ones I have seen that are bad when new. I may have to go back to rebuilding the SC tensioners and using the locks on them Let me know. Thanks, Eric