Drum stops turing periodically.
Buring smell.
Turn drum by hand , ok for a while.
Remove drum, belt is craked in sevral places.
In process of replaing belt.
How to check rollers?
Old stile idler without roller.
Plastic collar on motor is broken - is this a problem?

Thanks

Here are your parts
Parts for Whirlpool LEQ8000JQ0 Dryer - AppliancePartsPros.com

[COLOR="Blue"]How to check rollers?[/COLOR]
Check if the rubber looks OK with no flat spots.
Check for bearing slop on the shafts.
You could remove the wheels but often the tri-ring that hols them on will break and have to be replaced.
So I would only do this if there is bearing slop or they do not spin freely.
With them off you can then check the shafts for wear.

[COLOR="Blue"]Old stile idler without roller.[/COLOR]
I would replace this with a new idler wheel assembly.

[COLOR="Blue"]Plastic collar on motor is broken - is this a problem?[/COLOR]
Not sure what collar you are referring to.
As long as the motor pulley is where it should be and is tight, I would say it will be OK.
If it has a sharp edge I would file it down so it cannot clip the belt.

Also check the front drum supports.
Check all seals etc. in the unit.
Give the interior including the blower wheel a good cleaning.
This is also a good time to check/clean your vent system.

After reassembly turn the drum in the correct diretion before starting the unit.
Tt should turn fairly easily.