How do replace the bearing at the rear of dryer step by step

Are you sure it is the bearing? Squealing noise may indeed point at a bearing problem but more often at drum glider or roller problems . Black dust points at belt or motor bearing problems.

Note : the cost of replacing the mean bearing in money and time involved often exceeds the cost of a new dryer.

Here is my general list of how to check a squealing dryer :

Remove the rear panel, and have a look as to what is going on.
Check the drive belt : is it frayed? If so replace the belt.
Is the drum running against something?
Does anything look lose or broken?

Please be careful : do not touch anything while the dryer is connected to the power.

If you can not find anything, remove the power - take the power cable out of the socket and put it on the ground.
Note down how the belt is connecting the drum and motor.
Remove the belt (by taking away the tension from the belt this is easy).
Spin the (empty) drum a couple of times by hand, as fast as possible. Is it running freely? Any squealing noises? If so check gliders or rollers (at the front of the drum near the door, holding the drum in place)
Spin the motor a couple of times by hand, as fast as possible. Is it running freely? Any noises? If so check motor bearings.

If everything seems to look fine, squealing or shrill noises may also point at a problem with either the teflon gliders (replace gliders), with the plastic rollers (replace rollers), or with the drum bearing (replace dryer).

If you are sure it is the bearing, than the only option you have - besides replacing the dryer - is to de-install the entire dryer to allow space to remove tub and inner housing.

If needed you can come back to the board and discuss your findings!
If necessary contact me by private mail (click on my handle and follow instructions) to draw my attention. I will than reply here again.

Success !

:)