The rubber seals on a D1 are prone to cracking.
Is there a product that I can apply to protect it from cracking?

 

Armorall or any of the protectants wiped onto them will help keep them moist/nourished ... One of the brands have UV protection too

 

this is what I got from a article I have under my favorites- its about tires but same with all rubber and plastic. silicone is an inert material. The benefit of silicone is its ability to easily penetrate the tire’s surface and not evaporate. Some silicone-based dressings contain petroleum distillates as a cleaning agent. Petroleum distillates are harmful to rubber and vinyl, and will cause rubber and vinyl to crack. If you decide to use a silicone oil tire dressing, make sure it does not contain a cleaner.

2. Water-Based Dressings – The water-based dressings do not contain silicone oils, petroleum distillates, waxes, or other dangerous solvents that can harm and dull the surface of rubber and vinyl over time. Most water-based dressings use a water-based silicone, which offers a non-greasy, satin finish. The best products contain UV blocking agents to help keep tires and rubber from cracking, fading and hardening.

 

Aftermath431 provided some really great information. A Water-Based Dressing is better for your rubber seals than silicon-based dressing. While you may not get the slick glossy shine, your rubber seals will last a lot longer with a natural water-based protectant. My favorite is the 1Z Einszett Rubber Care Stick Gummi Pflege. This water-based protectant is formulated to protect the rubber in extreme temperatures and has natural UV blocking polymers. They bottle it in a shoe polish style applicator for easy application. You will be able to take care of your vehicle in a matter of minutes.

 

Yes, use silicone. The best kind is the silicone dielectric grease. It has a lot more viscosity than "Armor All" which is mostly water. Get the big can of silicone dielectric grease from auto-parts store and squirt a glob of it on a terry towel. Then massage it into the rubber seals. This is the recommended procedure for door seals in the owner's manual of another vehicle I have.

 

interesting info. i used some kind of silicone junk on my door seals. it was fine for the doors that were used often, but the other 3 got stickyish. i will be trying water base next.

 

I gave the advice I had, but after reading about Einszett products, I would give them serious consideration. I've long been a fan of the Meguiars professional product line for paint care, but think their non-paint products lack. Looking at Amazon reviews, it seems people have found the Einszett products to be a real hit. I've never tried them, but I can learn something new. The sponsor above has a better price than Amazon if you take the 10% off.

Besides the rubber care item, I learned something new about leather. In case you hadn't noticed, leather is not leather anymore. In the newer cars, it's all coated with stuff. Which means traditional lexol, beeswax and neetsfoot oil won't work. It will just sit on the surface of the coating and attract grime.

The leather in the Mercedes is amazing. It's like it doesn't wear. There's no cracks or even wrinkles yet. Now I understand why and that my old-school regimen doesn't add anything to the semi-aniline leathers. But Einszett has something for that.