In the world of weatherstripping, there are many different terms that may be unfamiliar to most people. If you’ve ever been confused when researching weatherstripping or rubber parts for your project, you aren’t alone!

Some of our part names like Trunk Weatherstrip or Windshield Gasket make it easy to know what that part is for. However, there are other parts that can contain terms or phrases that if unfamiliar to you, can make it difficult to understand if it’s what you need.

So, we’re diving deep into the terms we often use with our parts to ensure you feel confident when choosing replacement weatherstripping.

Basic Weatherstripping Terms

Dense Extrusion

A solid, durable rubber that is flexible enough to bend around a curve but does not compress much. Some of our parts made of dense rubber include: glass gaskets, rub rail inserts, window edging, insert trim, most RV slide out wiper blade seals and some rubber edge trim.

Sponge Extrusion

A closed-cell sponge rubber, meaning it does not absorb and hold moisture. These seals are soft and squishy, yet durable enough to withstand compression for long periods of time without losing their shape. Some of our parts made of sponge rubber include: trunk seals, auto, RV, and marine door seals, RV and marine compartment seals, RV slide out bulb seals, hood to cowl seals.

Clinch Seal

Also referred to as a “C-clip” seal or “push-on type” seal, these seals are designed to easily install by pushing onto a lip. They have a metal core that is fully encased in rubber to prevent rust and rubber teeth/flanges to create a durable grip. Most of these seals will feature a side, top, or double bulb attached, making for an excellent choice for automotive door and trunk seals, RV and marine door and compartment seals, as well as many universal applications.

Vulcanized

When we use this term it means that two or more pieces of rubber are molded together. For instance, when we make a windshield gasket it’s a complete circle of rubber made from an extrusion. The two ends of rubber are put into a mold with some additional rubber, heated up and vulcanized, or molded together, making them one unit that won’t separate. We do not glue or join our rubber ends together any other way.

Flocked

Parts that are flocked have a fuzzy, velvety coating. Flocked weatherstripping is ideal for sealing areas that experience moving surfaces because it’s smooth material eliminates friction. Most commonly, you’ll see this term with glass seals like glass run channel, window felts, and beltline weatherstrips.

Individual Part Names

Beltline Weatherstripping

These parts have many different nicknames like window fuzzies, anti-rattle, window felts, cat whiskers, window scrapers, window sweeps, etc. There is an inner beltline, sealing between the door panel and the inside of the window, and an outer beltline, sealing between the door and the outside of the window.

These parts mount on both sides of the opening at the top of the door panel where the window goes into. The beltline weatherstrips ‘sweep’ the window as it rolls up and down. They prevent window rattles while preventing water and debris from getting inside your door.

Roof Rail Weatherstripping

This vital weatherstripping is what seals the side windows when the windows are fully raised. There are two types: hardtop and convertible roof rail weatherstrips.

Hardtop Roof Rail Weatherstripping

This weatherstrip is typically a one-piece seal that mounts to the roof of the vehicle. The length and attachment style of the weatherstrip may vary depending on the year, make, and model of the car.

Convertible Roof Rail Weatherstripping

Unlike the hardtop, this weatherstrip is a series of molded parts that mount into the sections of the convertible top. The molded pieces are specific to each section of the convertible top.

Header Bow Weatherstrip

This weatherstrip, also referred to as front header bow or front bow weatherstrip, runs across the top of the windshield and seals between the convertible top and the windshield frame when the top is closed. It’s typically included in convertible roof rail weatherstrip kits, but is also sold individually for those who don’t need to replace all of the convertible seals.

Glass Run Channel

Run channel, both flexible and rigid, are U-shaped, fabric-lined channels that help eliminate window rattles and provide a smooth sliding surface for glass. There are 2 types of run channel- flexible and rigid.

Flexible Run Channel

This type of run channel has a corrugated metal spine that allows it to bend to fit the shape and curve of the window frame. It runs along the top and back side of the door glass to keep it secure and seal the window when it’s rolled all the way up.

Rigid run channel

This type of run channel has a rigid construction and only runs vertically on the front side of the door glass. It’s typically only found on the outer channel of a vent window division post. There are two variations: a continuous channel from the top of the vent window into the door, and a two-piece set that splits at the beltline.

There are two variations:

• Continuous channel from the top of the vent window down into the door
• Two-piece channel that splits at the beltline – the top piece for when the window is fully up and the bottom piece for when it’s rolled down

Mohair Liner

This is sometimes glued into a metal channel for use as run channel. Mohair liner is a soft, thin fabric with a thin rubber backing and is used to prevent glass from sliding against metal.

Rubber Run Channel

In the 1960’s, rubber run channel became the industry standard and remains in use on brand new vehicles today. This weatherstrip comes in many different profiles, sizes, and lengths.

Sash Channel

A metal U shaped channel that’s installed horizontally inside the door and supports the window glass from underneath. This is the channel that’s attached to the window regulator.

Sash Channel Filler

This piece of rubber is mounted to the bottom of the glass to protect it from the metal sash channel and to prevent rattles. This can be a molded part, specific to a certain vehicle or just a thin strip of rubber cut to length and pushed into the channel.

Lock Pillar Filler

This part, also known as U-Jamb or Door Jamb Seal, seals the gap at the bottom of the rear quarter window. Usually only found on hardtop and convertible models where there is no B-pillar.

Hood to Cowl

This weatherstrip, also known as Firewall to Hood or Cowl Lacing, seals between the top of the firewall and the back edge of the hood. It typically runs the width of the car and seals snugly to prevent fumes from entering the cab of the vehicle. Depending on the vehicle, the application style can vary from pins or clips to push-on or glue-on.

Vent Window Division Post Seal

For vent windows that have a two-piece seal, the division post is the straight piece that mounts to the vertical post on the vent window. The main vent window weatherstrip installs into the frame, sealing the other sides of the triangle. A division post seal often has attaching tabs that correspond to holes in the vent window frame. If yours doesn’t have holes, you’d simply glue it in.

Division Bar Gasket

This gasket seals the gap between separate pieces of glass in a split windshield or rear window. Often this part is already molded into the windshield or rear window gasket, though it’s also offered individually.

Hinge Pillar Weatherstrip

This part attaches to the body and seals between the A-pillar post and the front section of the door or vent window frame when the door is closed. It’s typically only found on convertible models and, depending on the vehicle and how the original parts were constructed, may be molded as a one-piece seal with the convertible header bow weatherstrip.

Leading Edge Weatherstripping

This is a molded strip of rubber that seals between the front and rear windows when the windows are fully raised. While depending on the vehicle, there are two different styles of leading edge seals, both styles are always installed vertically.

• Side Window – attaches to the back of the side window
• Quarter Window – attaches to the front of the rear quarter window

Splash Apron Seals

Pieces of masticated rubber attached inside a fender well to prevent debris from entering the engine compartments. Splash shields are usually partial cover pieces and as such, a vehicle may be fitted with only one splash shield, or multiple ones that cover different sections of the wheel well. These are attached to the vehicle using screws, bolts or clips.

A-Arm Dust Shield

This part functions the same as splash apron seals but are custom-shaped to wrap over “A” shaped control arms without posing an impediment to their motion.

Locking Strip

This is a rubber or mylar strip that’s designed to fit into a designated slot in a locking gasket, which are typically used for windshields or rear windows. A locking gasket gets placed on the vehicle first, then the glass is placed in the gasket, and lastly the locking strip is installed, which expands the rubber and locks everything in place, creating a airtight seal.

Bumper Bullets

Conical shaped bumper guards on the front bumper/grille assemblies of some post war American cars in the 1950’s.

Bumper Guard

A rubber piece mounted to the bumper to protect it from minor dents and scratches.

Gravel Shield/Stone Deflector

This is a molded rubber piece or extrusion that mounts onto the vehicle to prevent damage to the vehicle from stones deflected by the front wheels of the car.

Body Mounting Pads

Thick, heavy-duty pieces of rubber between the chassis and body of a vehicle. They prevent metal on metal rubbing and make it easier on the frame that supports the vehicle. Also often called biscuits.

Bumper Grommets

These grommets are specifically designed for vehicles where the bumper support arms pass through the fender. They seal the opening to prevent road debris from entering the fender while also providing a clean, finished look.

Miscellaneous Terms

Revulcanization

Here at Steele, revulcanization is the process of stripping the old, dried out and/or damaged rubber off a metal core and molding new rubber onto it, making it like a brand-new piece. We offer revulcanization services for parts like motor mounts, transmission mounts, harmonic balancers, accelerator pedal pads, vibration dampers, etc. on specific vehicles. See our website for more details.

Masticated Rubber

Strong rubber sheet containing random milled cotton cord reinforcement for making splash aprons, etc.

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At Steele, we’re more than just high-quality products, we’re your trusted resource for completing your weatherstripping projects with confidence.

Whether you’re working on a classic car or truck, street rod, RV, or boat, our expert team is here to help. If you have questions about weatherstripping or need product guidance, we’re just a call or click away.

📞 Call us at 800-650-4482
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