A flat tire due to an air-eating spool is a common cause of a decrease in tire pressure, requiring immediate intervention. Replacing this element doesn’t always require a visit to the tires if you know the type of valve installed and have a minimum set of tools on hand. The repair process depends on the design of the wheel: in some cases it is enough to twist the core, in others - a complete complete requisite is required. tyre-breaking from the disc.
The nature of the damage must be determined immediately. If the air comes out slowly and only when pressed on the valve, the problem lies in the contamination or wear of the spool. However, if the tire is deflecting regardless of the position of the valve, most likely, the nipple body itself or its seat on the disk is damaged. Ignoring the problem leads to uneven tread wear and the risk of tire destruction at high speed.
Owners of cast discs often have to face a more complicated procedure, as the standard nipple there can be hidden or have a design. Rubber valves on stamped discs change more easily, but require accuracy when pulling. The correct selection of the seal guarantees tightness of the connection and safety of the vehicle operation in all weather conditions.
Diagnostics of leakage and choice of valve type
Before starting a replacement, it is important to precisely localize the leak site. Apply the soap solution to the nipple area and watch for the appearance of bubbles. If the bubbles appear from the center of the valve when pressed, then it is out of order. slug. If the air is etched around the circumference of the base of the valve, where it enters the disk, then the entire nipple must be replaced.
There are two main types of valves used in passenger cars. The first is a classic rubber valve, which is installed in the hole of the stamped disk and is fixed due to the elasticity of the material and the downforce of the tire side. The second type is a metal nipple, which is used on cast discs and has a threaded mount with a nut and sealing cones.
⚠️ Warning: Metal valves cannot be installed in holes intended for rubber, and vice versa. The design of the disk landing place and the method of sealing are fundamentally different.
For diagnosis, it is also useful to use a manometer. A sharp drop in pressure after installing a new spool may indicate a microcrack in the valve body that is not visible to the eye. In such cases, you should not save on components - reliable brass-nipple It will last longer than a cheap silumin analogue.
Required tools and materials
Successful replacement of the nipple will require specific, but affordable tools. The main element is the spool squeeze (gold key), which is often built into the valve cap or sold separately in auto stores. Without this device, it will not be possible to unscrew the valve from the body.
Instead of a special key, a thin stitch or needle can be used, but the risk of damaging the thread or inner surface of the valve in this case increases significantly.
In addition to the key, you will need:
- 🔧 Passengers or special forceps for pulling rubber valves.
- 🧴 Soap solution or spray to search for leaks.
- 🔩 A set of wrenches (for metal nipples).
- 🧼 Clean rags for degreasing the surface.
If you plan to replace a rubber valve without removing the tire from the disc, lubrication (soap or silicone) may be required to facilitate the pulling of the new element through the hole. For metal valves, it is critically important to have a dynamometer key so as not to drag the thread and not deform the disk.
Replacement of the spool without removing the wheel
If the diagnosis showed that it is the valve that is poisoning, then a complete disassembly of the wheel is not required. This is the easiest and fastest way to restore the tightness of the system. First, you need to completely blow the air out of the tire, twisting the spool. This should be done carefully so as not to lose a small detail that can bounce under pressure.
After removing the old spool, wipe the inside of the valve with a clean cloth. Often the cause of leakage is a small grain of sand or oxidation, which prevents the valve from closing tightly. Install a new spool, screwing it with your fingers, and then carefully tighten it with a key. Do not make excessive efforts not to tear off the thin thread inside the brass case.
The final step will be to pump the tire to the rated pressure and re-check with soap solution. If bubbles do not appear, repairs can be considered successful. This method is suitable for both types of valves, as the spool is a standardized element regardless of the design of the housing.
Replacement of rubber valve on stamped disk
The situation is complicated if the rubber valve body itself is damaged. To replace it without removing the bus from the disk will require some skill and tools. The main difficulty is that the tire burticle tightly presses the base of the valve against the hole in the disk.
The replacement process is as follows:
1. Completely lower the air from the wheel and unscrew the spool.
2. Lubricate the new valve and hole in the disk with soap solution.
3. With the help of passages or a special tool, push the old valve inside the tire.
4. Snatch the base of the old valve with a hook and pull it out through the hole.
5. Tie a strong thread to the new valve or use a mounting blade to drag it through the hole outwards, ensuring it stands up straight.
⚠️ Note: When pulling the old valve, do not damage the tire cords and the inner surface of the tire with sharp edges of the tool.
After installing the new element, the tire must be pumped. A sharp jump in pressure should press a wide “fungus” of the valve to the inner surface of the disk, ensuring tightness. If the valve is crooked, the procedure will have to be repeated, since the skewed element will constantly poison the air.
Installation of a metal nipple on a cast disc
Owners of cars with cast discs often require replacement of a metal valve, which is fastened by thread. This process is technically simpler than tinkering with rubber, but requires access to the inside of the disc. In most cases, for a high-quality installation, the wheel will still have to be removed.
The table below shows the main differences in approaches to replacement depending on the type of disk:
| Parameter | Stamped disk | Cast disc |
|---|---|---|
| Type of valve | Rubber (most often) | Metal (threaded) |
| Removal of the wheel | Not necessarily. | Desirable or mandatory |
| Tool. | Passenger, hook. | Keys, dynamometer. |
| Hermetization | By pressing the rubber | Cone sealers |
To replace the metal nipple, unscrew the mounting nut from the inside of the disc. Remove the old valve, clean the hole of oxides and dirt. Install a new element, be sure to replace the sealing cones (usually come with a kit). The nut should be tightened with the effort specified by the manufacturer, but without fanaticism, so as not to crack the disc alloy.
Features of TPMS
If the car has a pressure control system, there is a sensor inside the wheel. When replacing the valve, be extremely careful not to damage it. Often, the sensor is part of the valve, and then it needs to be reprogrammed or replaced with a kit.
Typical errors and security measures
One of the most common mistakes is using inappropriate seals. An attempt to wind the tape or use a sealant instead of a regular cone on a metal nipple will lead to depressurization at the most inopportune moment. It is also dangerous to use rusty or deformed spools that can jam in the way.
☑️ Checklist before departure
Don't forget the nipple caps. Many consider them a decorative element, but in fact they protect the spool from dust, moisture and reagents. The absence of a cap accelerates the corrosion of the brass valve, which eventually leads to its jamming or loss of tightness. Metal caps with rubber seals provide better protection than plastic ones.
Critical: After any work with the wheels, even such simple as replacing the spool, it is necessary to check the balance if the tire was dismantled. Disruption of balance even a few grams can cause vibrations on the steering wheel and accelerated wear of the suspension.Frequently Asked Questions (FAQ)
Can a nipple be sealed temporarily?
Use sealant for repairing the valve itself can only be a temporary measure to get to the service. The sealant cannot withstand constant pressure and vibration, so it is not a complete replacement. In addition, the sealant can clog the spool itself.
Why does the new spool poison the air immediately after installation?
Most likely, in the thread or on the sealing surface remained dirt, or the spool is not twisted to the end. It is also possible to damage the sealing gasket inside the spool itself during installation.
How often should you change the nipples on the wheels?
Rubber valves are recommended to be changed at each seasonal reshoes or once every 2-3 years, as the rubber ages and cracks. Metal valves last longer, but require inspection of seals at each removal of the wheel.
A quality nipple and regular replacement of caps prolong the life of the pressure maintenance system and ensure safety on the road.