Tonneau Cover Drain Tube Locations?

FormerFordGuy · October 1, 2014

For those of you that have tonneaus that require drain tubes, where are you running them to exit the bed? These new trucks don't have any rubber plugs near the front/bottom of the bed. I just got a new undercover flex and am trying to figure out where to run them. I really don't want to drill holes in the bed of a newish truck. I see there are rubber plugs near the top of the bed for adding tie downs. I'm thinking of putting some 90 degree fittings on the tubes and running them to the forward most tie down plug. Anyone have any better ideas besides drilling 1/2" holes in the bed?

Imcrazy · October 2, 2014

Two thoughts: I have a drop in bed liner so I put mine in the area that is cut out for the tie down holes at the bottom. If you don't get some 90% elbows from home depot or lowes and use em to send the drains to one or two of the movable tie down locations at the top of the bed.

GTD · October 2, 2014

Bakflip G2 was included in my purchase. Installer drilled holes in plastic plugs in front of bed then ran short sections of vinyl tubing from drain fitting thru the plugs. Good idea except vinyl tubing was too thin and collapsed shut due to close bends.

Trip to Lowes and I found some 90○ plastic fittings with male/female ends. Female side fit snugly on drain fittings. I bought about 6 feet of heavy walled vinyl tubing heated the ends in a hot cup of water this let me slip the tubing over the male end giving a tight seal. I coiled the tubbing in a small can for a few days the tubbing took set and let me pass the tubbing again thru the holes and on down behind the black plastic trim piece between the cab and bed turned out good.

BaltimoreCaesar · October 2, 2014

I did this with my Retrax on both sides

jonny24 · October 2, 2014

Can't they just go out the drain holes in the bottom of the bed?

SLTJeff · October 2, 2014

I also have the undercover flex and installed it last week. I just used the existing drain holes at the bottom of the bed like Jonny suggested. The one on the passenger side needed to be bored out a little bit more, but 3 min with my drill bit took care of it. I may have gone overboard, but I also caulked around the opening to prevent water from getting in contact with the bare metal.

chuckl1218 · October 2, 2014

I have the Bakflip VP with drain tubes high in each front corner so I used the front two tie down holes/plugs. I did what you mentioned using the rubber plugs near the top of the bed for adding tie downs. Drilled holes in the two front plugs and put some 90 degree fittings on the tubes and running them to the forward most tie down plug so that the drains ended up between the bed and cab. No holes in bed, just the plugs. Fittings keep the tubes from collapsing.

chuckl1218 · October 2, 2014

Duplicate...sorry

FormerFordGuy · October 5, 2014

Can't they just go out the drain holes in the bottom of the bed?

The drain holes in the bottom of my bed are tiny. The tubes that come with most tonneaus are around 1/2" in diameter. Am I missing something?

jonny24 · October 5, 2014

The drain holes in the bottom of my bed are tiny. The tubes that come with most tonneaus are around 1/2" in diameter. Am I missing something?

I have the row of little holes, but at each corner is a bigger oval hole, maybe 1/2" by 3/8".

FormerFordGuy · October 6, 2014

I have the row of little holes, but at each corner is a bigger oval hole, maybe 1/2" by 3/8".

I see. My bed was rhino lined by the dealer so maybe they are plugged up with bed liner material.

Rewillia · October 6, 2014

For my drain tube install on my 2014 K1500 Denali it did not have plugs holes in either the bedsides nor the floor and I am using the Retrax Pro which as a box housing and drains on each side of its bottom side.

When installing it, I drilled 2-ea. 3/4 inch holes in the forward panel of the bed facing the back of the cab as the exit point for the clear drain tubes.

Using a good quality hole saw, I carefully drilled the 3/4" holes approx. 3' above the floor of the bed, in parallel to where they connect to the Retrax cover box. I then applied a light coat of 3M clear silicone on the hole faces followed by installation of 2 flanged face 5/8's ID rubber grommets (1"OD) that served to set and seal against the holes on both the interior and exterior sides of the bed panel. From there I ran the 1/2 OD clear drain tubes through them extending downward on the outside of the bed to where they can drain below the bed and the back of the cab. I also have a Bedrug bedliner and cut small slits where the drain tubes go through and enter the grommets.

I am satisfied that my install will serve to permit proper drainage without any long term damage, i.e. rust to the bed and the clear tubes are practically invisible. The pictures below show the entry point inside the bed and the exit point underneath the truck between the back of the cab and the front of the bed (both taken with a flash otherwise these are barely visible).

VMaxtastic · October 9, 2014

I just installed a Bakflip F1 today. Have to wait for my drill to charge before putting in the drain tubes. I'll take pics tomorrow

Isriam · October 9, 2014

the bottom of my gmc denali bed has a small hole in the corner. maybe quarter inch. i just put my drain tube behind the bed rug and down to near that little hole hoping it drains out before it soaks through the foam and carpet.