Jolteon, my Favorite Eeveelution sweeper, deals with Politode with Thunder or can cripple with Thunder-wave then Switch with Volt-switch. The set I use is: Hp(Ice), Volt-switch, Thunder-wave, Shadow-ball. He can damage Hippowdon with HP(Ice) a bit which will soften him up for your other Pokemon. A great addition to any team, he is extremely fast and has good S.Attack.
Espeon, is my next favorite, Most Politode's are Special and Espeon can simply Calm-mind boost and then OHKO with a strong Neutral attack. Grass-knot makes short work of Hippowdon. Magic-bounce can reflect all status attacks and entry hazards so you can switch into Stealth-rock/Spikes/T-Spikes and shoot them back at the opponent. Great for any team, good speed and high S.Attack. Set: Calm-mind, Psyshock, Grass-knot, Hidden-power(Fire/Fighting)/Shadow-ball.
Leafeon, a cool one, he kicks Politode and Hippowdon's rears easy with STAB grass type moves. Leaf-blade is the best option for that. He works best in the Sun though. He has great Attack, Defense, and good Speed. A good set: Leaf-blade, Return, Swords-dance, X-scissor. He does not have a good movepool though.
Those are the Sweeper Eeveelutions, Flareon can do Flame-charge and Sweep but I did not suggest him as he is Weak to both the Pokemon you are having trouble with. So I hope I helped.