Retrax install

zelmo · May 5, 2020

I got the RetraxPro ordered and have been reading the installation instructions. Cover will be put on a 2020 Denali 1500 SB.

The only question I have at this point regards the drain tubes. There are some plastic plugs at the front of the bed but I am sure that they are going to be too high to work correctly. Is that correct and if so is there anything that I need to be aware of before I start drilling holes?

cdh7917 · May 6, 2020

While my install is on a 2020 2500HD, perhaps it will help. I ran into the same issue you're describing in that the rubber plugs in the bed were above the drains on the Retrax storage piece.

I picked up some brass reducer barbs from Home Depot to go from 1/2" to 3/8". Picked up a 10' piece of 3/8" tube too.

Reducing to the 3/8" tube allowed me to put the drain hoses through a bed drain hole on each side that is in the floor of the bed, just behind the front wall of the bed.

Pro tip - using a hair dryer to warm up the tubing will help you get it into those holes in the truck bed. At room temp, the hose is somewhat stiff.

zelmo · May 6, 2020

At first I didn't want to use those holes so I didn't have an obstruction on the floor, but after thinking about it if that is ever a problem I can just remove them temporarily.

Is there a reason you went to the trouble of reducing the tube to fit in the existing holes instead of drilling them out to accept the 1/2" tube?

Bo Evans · May 7, 2020

Make sure and get your rails tilted outward slightly so that the outside edge sits down nicely on the bed rail. This will aid in proper drainage...

TVelar · May 7, 2020

I used the two existing holes in the bed floor just rear of the cab. Not sure if it was the same 1/2" hose or not, but with a little bit of work the hoses fit in fine. Did not want to drill into a new truck. And honestly if you need to put something in the truck like a sheet of plywood and you know it wont be pouring rain, just pull the hoses out and put them back in after.

cdh7917 · May 7, 2020

22 hours ago, zelmo said:

At first I didn't want to use those holes so I didn't have an obstruction on the floor, but after thinking about it if that is ever a problem I can just remove them temporarily.

Is there a reason you went to the trouble of reducing the tube to fit in the existing holes instead of drilling them out to accept the 1/2" tube?

Drilling would have been the easier option, but I wasn't too keen on taking a drill bit to a new truck. Since putting in the Retrax, I have also added the rubber GMC bed mat. I carefully measured and cut holes in it for the hoses to pass through.

NHM25 · July 24, 2020

Odd question but here goes... I live in Phoenix. We haven't gotten rain in over 100 days. How necessary are those drain tubes? I just hate the thought of having to drill and/or obstructing part of the floor and losing more clean space.

AMRx17 · April 27, 2022

On 5/7/2020 at 8:51 AM, cdh7917 said:

Drilling would have been the easier option, but I wasn't too keen on taking a drill bit to a new truck. Since putting in the Retrax, I have also added the rubber GMC bed mat. I carefully measured and cut holes in it for the hoses to pass through.

Do you mind sharing a picture? I’m currently in the same situation of not wanting to drill and I also have a bed mat. I want to see how it looks to get an idea!

GETGONE · April 27, 2022

I didn't want to drill either so I did the same thing and got reducer barbs and run the smaller hose through the existing holes. I have the factory spray in liner and I don't want to cause rust enlarging or drilling new holes. The hose with the Retrax is too thick/large to fit into the existing holes. I tried and gave up. I tried to redo the hose and just use the smaller hose and try to stretch it to fit on the Retrax plastic pieces that snap into the bottom of the metal housing. That didn't work out either. For some reason now, I was able to just slip fit the smaller hose inside the Retrax hose then through the holes. I had issues with the hose coming off the Retrax nipple since it is just a slip fit with the brass reducer hanging on it. I didn't have any hose clamps the right size to put on it. I'll have to pick some up or try to find a thinner diameter hose that fits the Retrax nipple that can be shoved through the bed floor holes. This is the only picture I have from the original install and it's hard to see the hoses.