I've lost the manual and I can't remember how to change the sand paper belt. There is a lever on the side which I've sort of tried but don't want to pull it too much incase its the wrong thing HELP! Chris

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yes ther should be a knob on the top front roller (top side) this should affect tracking , also make sure tension taker (lever for changing belt) Is fully off so that belt gets its full tension , if the belt doesnt get full tension it will walk side to side

The 7447 does not have a release lever. 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.

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.

it could be a dirt buildup in front of the yoke not allowing it to fully extend. could also be the rear roller is worn down, I would recommend going to Makitatools.com and downloading a breakdown to see how to remove the mechanism to clean . the yoke should snap when the lever is released to install the belt.

there is a knob that moves the front roller [rotates] the roller side to side to center a moving belt - the grit belt. the roller has a slight bevel from the center out to the edge. both edges. use the trigger to start the belt in short spurts and move the knob. eventually you'll get the belt to track on center.

Look on the side of the tool between the guide and drive wheels for a lever

Loosening or disengaging this lever will take the tension off of the belt so that it can be removed

If there is no lever, there will be a tension know on the front of the tool that you can loosen to remove the belt

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.

There is a lever on the side of the unit, flip the lever and then slid the belt off.

On my model 315.11720 3"x21" Craftsman belt sander to change out sanding belts you push the front roller in until it clicks to lock in its retracted position (a pry bar may help here), switch out sanding belts then unscrew the tracking tensioner a bit on the opposite side with a allen wrench until the roller snaps back in place. I never remember anything about using a screw driver to force it back forward position again. Then readjust the tracking if necessary with a few short sanding load tests and you're good to go. Oil is dropped in the front roller center by removing the flat head screw - it should say "Oil Here" around the screw.