(09-21-2023, 02:31 PM)jteneyck Wrote: Look at the back of the slide in the cabinet.  See that L shaped bracket.  I'll bet it's mounted to the back of the cabinet or a cleat that runs in front of the back.  You can buy slides with a similar bracket, including Blum's undermounts, that allows the slide to be mounted at the back, so you don't have to pad out the interior flush with the faceframe.  The bracket also allows you steer the drawer front for a flush fit.  

You will not be able to use Blum's undermounts unless you are very lucky.  The drawer bottom needs to 1/2" above the bottom of the sides, and the drawer length needs to be exactly 18", 21", etc, whatever length slide you are buying.  Side mounted slides are much more forgiving in those regards, and will cover the holes from the slide you now have.  K&V make some very nice soft close side mounted slides.  You'll see the rear mounting brackets and some K&V slides at this Link.  And their soft close side mounted ones:  Link 2

John