Advice regarding drilling holes for tonneau drain tubes - oem spray on liner
I have installed a Retrax Tonneau cover (well, almost) on my 2019 3500HD. I still need to make holes for the drain hoses. I guess I didn't realize it drains from the bottom of the roll-up box rather than from the top of the rails (duh) so I can't use the factory punch outs as they are way too high.
I need to make holes big enough for the two tubes, which are about 7/8" in diameter each. Going through the bed wall against the cab seems to be the most logical place.
Any advice on drill bits? getting through the spray on-liner cleanly? protecting the newly bare metal? grommets to keep the hose in place? etc?
Thanks for any thoughts.
2015 2500 CCSB LTZ 4wd Z71 brownstone/cocoa
2019 3500 CCLB LTZ 4wd SRW pearl/cocoa
2016 Spark gas CVT LT2 black/black
2006 DTS Lux III green mist/shale