Why won't my wide belt sand paper retract correctly?

The rubber compound on the drive roller is missing and is smooth hard plastic ??? replace the drive roller or your bushings are worn is the front rol not bent by a fall?

please be more specific!!
guessing - bench top disc/belt sanders' discs usually use stick on backed sand paper discs ;)

I have a used machine for sale looks good and it works..... contact me at my [email protected]

To change belt:
1) Put front roller on floor and push down until roller locks back.
2) Put on new sand paper.
3) Loosen tracking screw until front roller is released.
4) With sander running, use tracking screw to center belt.

To change the belt, you must release tension of the rollers by pushing the front roller straight back until you hear it click and lock in position to change paper. Remove old paper and replace with new paper. Make sure if new paper has directional arrows to install properly.
Now you must release the front roller to put tension on paper. To do this push the front roller from the side that has the adjustment screw. This will release the front roller and allow it to go back into position. Be careful as it pops back quickly and with some force.
Turn on sander and adjust centering of paper with adjustment screw found near the front and side of sander.

If it's the kind with a round disk sander and a wide belt sander, as far as I know belts and disks are still available. There is not much else to wear out. Make sure you test it before purchase.

All sander will have two adjustments. The first is to release the sanding belt by retracting the position of one of the rollers. The second adjustment moves one of the rollers belt tension from side to side. The roller angular position is changed, sometime by a single knob or screw, and sometimes by two separate adjusting screws.

Have you tried adjusting the tracking slightly to the opposite side to which the belt comes off this has worked for me on my Bosch

You did not specify how the sanding discs are meant to be attached to your sander's backing pad.  My experience with this type of problem is material from the sanding process builds up on the backing pad and does not allow the sanding discs to adhere properly.  If you have a velcro type system, clean the hooks on the sander's backing bad by soaking the pad's face in a plate of paint thinner for 20 to 30 minutes then use a wire brush to remove the rest of the paint physically.    For adhesive pads clean the sander's backing pad surface with denatured alcohol.  Do not use isopropryl or rubbing alcohol as this may not be 100% alcohol and could contain a lubricant like glycerin.  When the sander's backing pad is completely dry and clean it will hold adhesive backed pads fine.    Flaky paint is best scraped off before sanding, use a wide putty knife or a paint scaper to remove large flakes before sanding.  This will minimize airborne dust and cleanup.    For best results with adhesives, always keep your surfaces  clean!    Good luck and happy sanding!  Michael Mittelsdorf   

# Ensure that sanding belts are not too tight or too loose. Never operate a sanding disk if the paper is loose. # Use the correct grade of abrasive material for the job. # Ensure that the distance between a circular sander and the edge of the table is not greater than 1/4 inch. # Do not push materials against sanders with excessive force. # Sand only on the downstroke side of a disk sander. # Do not hold small pieces by hand. Use a jig for pieces that are difficult to hold securely