up & over garage door catching on the bottom

[DIYspanner]

This is the bother

There's no adjustment on the brackets at the top. About 1/4" clearance between the door and the wood beam that the brackets are fixed to.

How easy is it to grind concrete with a 75x533 60grit belt on a belt sander?
If I can get about 1/4" of concrete base removed, the door will be clear.

 

[Burnerman]

Quite a task, that one.....I dont think you would get far with a belt sander but an angle grinder with a stone cutting disc would be better. If your luck is in, you wouldnt need to shift much material but it could cause water to collect there.
John

 

[DIYspanner]

A number of options to consider although yours sounds favorable John, cheers.

Only snag is not having an angle grinder but that's easily solved.

 

[Tigercubrider]

You don't need to remove much as the arc takes care of most of the area in front.
I would look for a rubber moulding that provides some give (like a "D" profile)
Draw some lines on the floor the width apart to accept the D profile, and cut two parallel lines to accommodate the Rubber. Remove the concrete in between the lines, with a hammer or similar- maybe a stone grinding wheel?

Trial fit the profile and adjust the depth of the slot to suit, then glue the rubber into the hole so it just compresses once the door is closed.