Replacing RV slide-out seals

Most modern RVs come with slide-outs that open to provide extra living space inside the rig. These slide-outs have rubber inner and outer seals, somewhat like windshield wipers, to keep out moisture, dirt, and debris. 

Our fifth wheel came with four slide-outs. Since we park our rig in Arizona for five to six months at a time, the outer slide-out seals — sometimes called wiper seals or weatherstripping — take a beating from the intense sun. 

Bob had added a layer of duct tape to the seals around the slide-out that gets the brunt of the sun’s rays and heat, and that lasted for a couple of years. But the time came to replace the “MacGyver” job with new RV slide-out seals. Here’s what that involved.

Gathering supplies

Bob searched and searched for a replacement seal but couldn’t find the size or shape we needed. Amazon didn’t have it. Etrailer didn’t have it. Other places didn’t have it. After much research, he finally found the right thing and bought 15 feet from Steele Rubber Products: 2⅜-inch peel-n-stick wiper seal.

On a cloudy day, we gathered other supplies we’d need for the RV seal replacement project, including:

• A putty knife to remove the old seal
• Goof Off to remove gummy residue
• Acetone to clean the area
• Disposable gloves
• A ladder
• Something to kneel on
• Scissors to cut the new material
• A utility knife to make notches around the slide mechanisms

Removing the old seal

Bob peeled one side of the existing slide-out seal on the trailer from bottom to top. It came off with a little force and exposed a gummy mess. We knew we couldn’t attach the new seal to that if we wanted it to stick long term.

Kneeling on a discarded mudflap from a semi-truck with putty knife in hand, Bob attempted to remove the residue, but it just gummed up more. So he donned a pair of disposable gloves, poured some Goof Off on a rag, and applied some elbow grease to remove the stickiness. That worked. 

After reaching the halfway point, Bob transitioned from the mudflap to the ladder to reach the top. He went over the attachment strip again with acetone on a clean rag to ensure a clean surface. 

Prepping the new seal

Before we could attach the new material, we had to cut the length we needed from the 15-foot roll. We stretched out the seal we had removed and laid the new rubber on top of it. Trying to keep the new material flat proved challenging as it wanted to roll back up. We flattened it as best as we could, and Bob marked the length we wanted. Then he used scissors to cut it from the roll.

We put the freshly cut piece on our concrete pad and placed the old seal on top of it to use as a template. This showed us the notches we needed to cut in the new material to allow room for the slide-out mechanisms, but it looked like we had cut our piece too short. Since we didn’t have enough material left to cut a new piece, we moved forward. After marking the notches, Bob used a utility knife to cut them out.

Affixing the new seal

We took the fresh piece of rubber to the other side of our trailer. Bob put the ladder in place, as we wanted to start at the top this time and work to the bottom. That way, if the new piece was indeed too short, it wouldn’t matter as much. The top would be protected.

We held up the new seal to align it with the strip for attachment. Slowly and methodically, Bob unpeeled the backing of the new rubber and affixed it to our rig while I held the ladder. When Bob got halfway, we removed the ladder and continued the process to the end.

With the new rubber stretched out and attached, it turned out to be a little long. Hooray! Bob trimmed the excess, and we admired our work. 

Before we could count the project complete, however, we had to repeat the process on the other side of the slide-out. My office slide-out prevented us from getting the ladder into place on the other side. 

I went inside the rig and moved things out of the way to be able to close the office slide while Bob detached the bottom of the sunscreen over that slide. I closed the slide-out, giving us ample room to complete the project. 

We only replaced the seals on the one slide-out, as the others were in much better shape. If the need arises to replace them too, we have confidence we’ll be able to do the job.

You might also like Replacing an RV roof vent fan.