Van keeps jumping time
 

I have a 91 Mpv minivan and the timing tensioner broke, we replaced that and retimed the van. It drove fine for a day or two then jumped time again. Once again we retimed it only this time we made it about 5 miles and it jumped time again. What could be causing this to happen? It has a new belt and tensioner (the one that has to be filled with fluid) and the gears are all ok. Is there something that we are missing or what. Any help would be appriciated.
Thanks in advance

RE: Van keeps jumping time
 

What do you mean "The one that needs to be filled with fluid". Assume you are talking about the actual hydraulic tensioner that applies the needed tension to the drive belt and not a bearing. This tensioner should not need to be filled with fluid. If you removed that small allen head plug in the base of the tensioner then throw it out and get another. Try taking that tensioner out and trying to push the piston back in the tensioner body. If you can push it in at all without the help of a vise or hydraulic press then it is collapsed and has to be replaced. Make sure to also check the tensioner bearing pivot. They have a tendency to wear which throws it out of parallel with the belt and causes very rapid edge wear on the belt. The pivot shaft should be nice and smooth the full lenth of the shaft.