In the process of operating the car, the body is constantly exposed to an aggressive external environment, and even microscopic holes can become a source of serious problems. Rubber plugs 20 mm diameter is one of the most common sealing elements used to close technological openings, attachment points of cabin elements or former valves. Their proper use prevents moisture, dust and dirt from entering the structures of the body, which is critical to maintaining its integrity.
Ignoring the need to install such seals often leads to hidden corrosion, which is difficult to notice in the early stages. Water penetrating through unclosed holes of 20 mm diameter can accumulate in the cavities of spars, sills or doors, causing the metal to break down from the inside. That is why the use of quality EPDM or silicone Traffic jams are not just a cosmetic procedure, but an important preventive measure to extend the life of the vehicle.
In this article we will discuss in detail the technical features of these products, methods of their selection and nuances of installation, so that you can independently perform the work professionally. Understanding the physical properties of rubber and the mechanics of interaction with metal will help to avoid common mistakes that even experienced craftsmen make when repairing bodywork or tuning.
Types and materials of manufacture of traffic jams
The auto parts market offers a wide range of products, and the choice of material directly affects the durability of sealing. The most common material is EPDM rubber (ethylene-propylene-diene monomer), which has outstanding resistance to ultraviolet radiation, ozone and extreme temperature changes. Unlike conventional rubber, EPDM does not crack in the cold and does not “blown” over time, maintaining elasticity even after several years of operation under the scorching sun.
The second popular option is thermoplastic rubber (TPR)It is often used in mass production due to its low cost and recyclability. However, for responsible units, where maximum tightness and resistance to chemical reagents (oils, gasoline, brake fluid) are required, it is better to choose specialized rubber mixtures. Cheap analogues can quickly deform or lose shape, no longer performing their function.
It is also worth noting the difference in design: stubs can be whole, with a flange, with a burtic, or have a complex geometry for fixing in specific holes. cone-shaped Often allows the same plug to sit tightly in holes with a small diameter spread, for example, from 19 to 21 mm, providing tension due to the elasticity of the material.
When choosing, it is important to pay attention to the hardness of the material on Shore. Too soft plug can easily fly out under the pressure of water when washing, and excessively hard - damage the edges of the hole or not provide proper fit. The optimal balance is possessed by medium-severity products, which are easily installed with fingers, but are reliably held in a landing place.
Area of application of 20 mm diameter caps
The 20mm diameter is the standard for many technological holes in the modern automotive industry. Most often, such plugs can be found in the lower part of the doors, where they close access to the internal mechanisms of windows or serve as drainage holes. At this point, the material’s ability to withstand constant contact with water and road reagents without losing its properties is critical.
The second common application area is the arches and the bottom of the car, where the harnesses of the electrical wiring or the tubes of the brake system pass through the holes of such a diameter. Here. rubber-sleeves And plugs perform a dual function: seal the cabin from the external environment and protect the wires from rubbing on the sharp edges of the metal. The lack of such protection may lead to short circuit or leakage of brake fluid.
During body repairs or installation of additional equipment (for example, parking sensors, rear-view cameras or abnormal acoustics), new holes that require camouflage often appear. If you have dismantled the old element, but you do not plan to install a new one, a high-quality stub will be the ideal solution for restoring the tightness of the body.
Hidden locations for stubs
Often, plugs with a diameter of 20 mm are hidden under the decorative linings of the rapids, in the niches of the trunk under the carpet, as well as in the engine compartment to close unused ventilation channels. Checking these places when buying used cars can tell about the history of its service.
Do not forget about tuning projects, where additional intercooler nozzles or elements of the cooling system can be output through such holes. In such cases, special pass plugs with a central channel are used, but the principle of their landing and sealing remains similar to whole products.
Criteria for the selection of quality sealers
When selecting plugs for holes of 20 mm, it is necessary to take into account not only the diameter, but also the depth of the seat. If the hole is deep, a product with an elongated “body” will be required to ensure reliable fixation along the entire length of the channel. Otherwise, a short plug can fall inside the body cavity or, conversely, sit loosely at the edge.
An important parameter is the temperature range of operation. For Russian conditions, where temperature changes can be more than 60 degrees during the day, materials are required that retain elasticity from -50 ° C to +120 ° C. Oil resistance It also plays a role, especially if the plug is located in the engine compartment or the lower part of the body, where technical fluids can get.
Pay attention to the presence of additional stiffness ribs or grooves on the side surface of the plug. These design elements create additional friction and vacuum effect, which significantly improves the retention of the product in the hole under vibrations and dynamic loads during the movement of the car.
Buy plugs with a small margin in diameter (about 0.5-1 mm more than the hole), as the rubber may shrink slightly over time or lose its original shape, and the supply of tension will compensate for this.
Visual inspection can also prompt the quality of the product: the surface should be smooth, without burrs, air bubbles or uneven coloring, which indicates a violation of production technology. Cheap Chinese counterparts often have a sharp chemical smell, which indicates the use of low-quality recyclables.
Technical characteristics and comparison of materials
To understand the differences between materials, it is worth considering their physical properties in numbers. This will help to make an informed decision when ordering components for responsible components of your car.
| Characteristics | EPDM Rubber | silicone | PVC/TPR |
|---|---|---|---|
| Operating temperature | -50°C ... +130°C | -60°C ... +200°C | -20°C ... +80°C |
| Resistance to UV | Great. | Excellent. | Medium |
| Oil resistance | Medium | Low. | Tall. |
| Term of service | 10 years. | 15+ years | 3-5 years |
| Price. | Medium | Tall. | Low. |
As you can see from the table, EPDM It is the “middle ground” for most automotive tasks, combining affordability and high performance. Silicone is superior to it in temperature resistance, but inferior in mechanical strength and oil resistance, making it less suitable for installation near the engine.
PVC or TPR-based materials are suitable for temporary solutions or places not exposed to intense sun and chemistry. However, for the long term, the material savings can come out sideways, requiring re-disassembly and replacement after a short period of time.
The choice of the material of the plug should be based on specific operating conditions: for the external elements of the body, the priority is resistance to UV and water, and for the underhood space - heat resistance and chemical inertness.
Instructions for installation and replacement of stubs
The process of installing plugs with a diameter of 20 mm seems simple, but requires adherence to a certain technology to achieve the ideal result. The first step should always be a thorough surface preparation: the edges of the hole should be cleaned of old paint, rust, glue residues or previous seals. Any dirt on the edge of the metal will violate the tightness of the fit.
After cleaning, the metal edge is recommended to degrease with alcohol or a special cleaner. If the hole has sharp edges, they should be carefully treated with a topfill or sandpaper so that when installed, the rubber cap itself does not damage. This is especially important for the thin-walled elements of the body.
☑️ Checklist for installation
To improve fixation and sealing, a thin layer of automotive silicone sealant can be applied to the side surface of the plug before installation. Do not overdo it: the sealant should act only as an auxiliary agent, and not as the main fixing element. Excess glue immediately remove dry rags.
Installation is made by uniform pressure over the entire area of the plug. If the plug sits tightly, you can slightly lubricate it with a soap solution to facilitate entry, but in no case use solidol or litol, as petroleum products can destroy the structure of the rubber. After installation, allow the sealant (if used) to be polymerized according to the instructions on the package.
⚠️ Attention: Never use acetone-based solvents or aggressive chemicals to degrease rubber products, this will cause them to quickly break down and lose elasticity.
Typical errors and precautions
One of the most common mistakes is to try to install a larger diameter plug using force. The stretched rubber creates a constant stress at the edges of the hole, which over time leads to deformation of the metal or rupture of the seal itself. If the plug does not enter - it is better to squander the hole or pick up a product with a smaller diameter of the landing part.
Also, masters often ignore the state of the edges of the hole, relying only on the elasticity of the rubber. Rust under the cork continues to develop, “eating” the metal, and after a year or two you may find that the stub fell out of itself along with a piece of rotten bodywork. Therefore, cleaning and anti-corrosion treatment of edges is mandatory.
Another mistake is the use of inappropriate lubricants. As mentioned, petroleum-based products are detrimental to many types of rubber. Use only specialized lubricants for rubber seals or a common soap solution that leaves no harmful traces after drying the water.
⚠️ Attention: When installing plugs in the drainage holes of the doors, make sure that you do not block the main water drain. Such plugs often have a valve or slot, which must be located strictly in a certain position (usually down).
What happens if you ignore the sealing?
Water that enters the closed cavities through an open hole will not be able to evaporate. This will lead to the formation of condensate, which mixes with dust and turns into abrasive dirt, accelerating corrosion many times faster than just moist air.
Frequently Asked Questions (FAQ)
Can 20 mm plugs be used for holes with a diameter of 21-22 mm?
The use of a plug of smaller diameter in a larger hole is possible only if the difference is minimal (up to 1 mm), and the plug itself has a pronounced cone shape or wide elastic cuffs. However, it will be more reliable to choose the product exactly to the size or use a sealant to compensate for the gap, although this is a temporary solution.
How to remove an old, petrified stub without damaging the body?
Carefully tuck the edge of the plug with a thin flat screwdriver, preheating it with a hairdryer (not overheating the metal) to soften the rubber. If the cork has collapsed, the residues can be removed by scrolling them with your fingers or using tweezers, trying not to scratch the metal.
Do I need to remove the stub before installation?
Lubrication is not mandatory, but it can make it easier to install tightly seated stoppers. It is best to use a soapy solution. Special rubber lubricants (silicone) are also acceptable, but avoid getting oil or solidol on the working surface.
How to replace the standard stub if the original is not sold?
Alternatively, you can use universal rubber stoppers from the range of auto stores, choosing the nearest size. There are also sets of cut plugs that can be adapted to the desired diameter, cutting the excess, but their tightness will be lower than that of whole products.
How often should I check the condition of the plugs?
It is recommended to conduct a visual inspection of the stubs at each scheduled maintenance of the car or washing the body (once every six months). Pay attention to the appearance of cracks, loss of color (burnout), or violation of the density of the fit.