Hey brotha, I can't actually help you with this as I have no experience with vac pumps in use with extraction, but, I'm sure whatever the issue is causing it, it could be fixed with a check valve. Still, try and be specific about your issue to increase the chance of getting help. I'm assuming you have an issue with vac pump oil in your extraction. I'd think this could be remedied, unless for some reason it would purge long after the concentrate was burnt out. Granted, even if that were the case, I'd figure you could use some solvent to separate it from your extract. But, I have no idea. Again, try and post a more specific issue and hopefully someone will come along and help you, if you have not found the solution already. If you happen to have found a fix, you could always post that here too, of course. Good luck.