LANCE 1985 – Slide-Out Seal Replacement

I got a text from a buddy last week: a Lance 1985 came through his shop with a quote of $2,100 for slide-out seal replacement, labor included. He asked if I’d ever done it. I have — several times — and it’s nowhere near that number if you’re willing to spend an afternoon on it yourself. The catch: water damage hiding behind a failed wiper and base seal can multiply that bill ten times over before you even notice it’s happening. On the Lance platform, those two seals fail together, and when they do, moisture creeps into wall cavities and floor substrates silently for months. I’ve opened up slideouts where what started as a $60 parts problem had become $2,500 in structural rot. This one’s a straightforward DIY if you go in knowing where the traps are, which seal profiles actually seat in the Lance’s tolerances, and what corroded hardware to swap while you’re already deep in the job.

The Two-Seal Strategy: Why One Wiper Alone Won’t Save Your Walls

A 1985 Lance slide-out assembly depends on two seal components working together — a wiper on top and a base seal along the bottom track. Neither one handles the load by itself. The wiper compresses and splits from thermal cycling, the base hardens and pulls away from the frame, and suddenly you’ve got two independent pathways for water to bypass both. You absolutely need to replace both pieces in the same session, or you’ll be back inside the walls six months later.

What works

• Sourcing the 018-341 EK and 018-312-EKD as a matched pair means one order, one shipping cost, and no halfway-through-the-job realization that the first seal alone is inadequate.
• The 35-foot coil length on each seal covers your entire slide perimeter with 8-10 feet remaining for repair patches or other trim work down the road.
• When both seals are properly seated and compressed, the slide operation becomes noticeably smoother, the box feels less sloppy, and condensation no longer pools on the flooring after temperature swings.

What doesn’t

• These seals won’t stick to 40-year-old aluminum unless you strip off every speck of old adhesive residue first — a scraper alone won’t cut it, and poor surface prep guarantees the seal will migrate sideways within weeks of installation.
• The mounting groove on the Lance frame requires hands-on trial fit; the seals come slightly oversized intentionally, so expect multiple trim-and-test cycles before the profile seats flush.

I second-guessed whether 35 feet was actually enough coverage until I ran the numbers and realized I’d overestimated the perimeter by nearly 40 percent — don’t repeat that mistake, and measure your actual slide-out frame before ordering. Grab the 018-341 EK Slide Out Rubber Seal & 018-312-EKD RV Weather Stripping Exterior for RV Camper, 1′ x 15/16′ x 35′ and 1/2′ x 2.75′ x 35′ Combo Slideout Wiper Seal and get both seals done in one job.

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