Kenmore 70 series dryer

did u remember to place the tensioner spring back into the slot

You need to remove the dryer casing so the drum is viewable. You need to release the tension on the tensioner pulley and slide the belt off the pulley, then you can slide the belt off the drum. Replacement is the same as removal. The tensioner pulley can many times be accessed through a compartment in the rear of the dryer.

Unplug the dryer.
Remove the lint filter.
Remove the 2 screws at the lint filter opening.
Use a putty knife between the top lid and the front panel to release the clips.
They are about 2 inches in from right and left sides where the top meets the front panel.
Lift the lid towards the rear of the dryer.
Look inside the top right and left corners of the front panel and remove the screws holding the front to the cabinet. Remove the door switch wires and set the door aside.
Place the new belt over the drum,ribbed side towards the drum.
Look under the drum for the belt tensioner. It is S shaped with a wheel on it.
Place the base of the tensioner in the slots below the motor pulley.
Feed the right side of the belt through the opening under the wheel with the smooth side of the belt touching the wheel.
Place this side of the belt over the motor pulley with the ribbed side touching the pulley.
Replace the front panel.
Hook up the door switch wires.
Replace the panel screws.
Reattach the top lid and lint filter screws. Replace the lint filter.
Plug in the dryer.

The bottom of the belt goes straight from the drum to the motor.  The tensioner goes on the top portion of the belt.

sounds like the plastic take-up pulley on the motor which is spring loaded to keep the drum belt tight. You will have to replace the tensioner which should, depending on the model, include a new plastic pulley.

broken belt......simple fix.......remove lint filter from top 2 screws remove.........insert screwdriver between top & front push down to pop top......1 screw on each side holding front on at top remove them....front will then pick up off the 2 remaining clips at the front bottom.....spin door around to the side belt should be laying in the bottom of the dryer or around the tub but broken.......hope this helps......check back.......

There are 2 slots underneath the motor pulley.
The flat part of the tensioner goues in these slots.
The roller wheel will then be on your left.
With the belt around the drum, run the belt under the wheel and through the tensioner, then over the motor pulley.

To fit the new belt, you will need the idler pulley (tensioner)...

The idler pulley fits in the slots on the bottom of the cabinet (in front of the motor) with the wheel or glide facing the left side. Place the belt (grooves inward) around the drum. Pull the belt through the middle of the idler pulley from the left side. Once the belt is pulled through the idler pulley, pull it around the motor pulley (this should force the idler pulley to "open up" and add tension).

If you still need help, I will try to provide you with a diagram shortly.
Good luck!

Take the belt with you to an appliance store and they will match it up. Much like a fan belt on a car. You won't necessarily need the model if you have the belt. Next, it sounds like your assembly is broken. If this assembly looks to be in pieces, you may need a new one.

it could be a worn motor bearing, but they usually last for 20 years, i would guess that you have a worn drum roller, the thing that holds up the drum and looks like a wheel.
if your sure the motor has a worn bearing then replacing the motor is not easy as you have to unscrew the blower wheel from the motor shaft.
it also may be that you are talking about the idler pulley being worn. it is the device that holds tension against the belt and they also will wear out and be "wobbly"