My central kenmore vacuum wont suction

Question

the large cannister was full and the vacuum lacked suction so i emptied the cannister but it still wont suction properly? i have tried to clean the cloth filter on the bottom of the large canister in the basement and i have checked all the outlets and they all have good suction. it could be that the hose itself is blocked. i dont have soemthing long enough to snake it through and see if it is unblocked. this prob started though when the cannister became too full and we emptied it but after that the suction sucked. thanks