Slide out wiper seal advice needed

Your local rv store should have a replacement, just remove the old one and take it to the store.

My seal on my previous Travel trailer did the same thing. It has to do with the cheap rubber used and the Florida sun. It did this even though I religiously lubricated it with slide out seal lubricant. I was doing just that when it tore apart wiping it down previous to application right before selling it. I called a mobile RV guy who ordered the part and installed it. Found the guy on Craigslist.

steelerubber.com

I replaced the top wiper on a 2004 Keystone Outback 5th we had. It was a very simple job, it pulled out of the groove it fit in and the new went right back in. I lubed the groove and wiper with WD 40 to ease the installation. I made a sketch by tracing the end of the old one on a sheet of paper, took measurements and got on the internet and bought a stock length then cut it to the needed length +1". The side wiper was the same as the roof (top) wiper. I'll do some looking and see if I can find the internet address of where I purchased it.

Sorry it didn't pull out of a groove it pressed onto a male trim. It had a spring loaded V that pushed on the male trim piece. If you go to pellandent.com and look at the trim pieces Model 19-G8120 and model 19-G8138A they are similar to the wiper I replaced. They press on to the male trim firmly by hand. This is where I purchased what I needed.

Not sure WD-40 would be the best thing to use on rubber. Silicone would of been better and wouldn't hasten deterioration of the new seal.