Tire valve stems are the valves located in a vehicle’s wheel where the tires are inflated from. They contain a spring-loaded valve core that seals itself using the air pressure inside of the tire. Over time valve stems may get old, crack, become brittle, or begin to leak, causing larger problems with your tire and your driving experience.
When valve stems begin to leak, the tire will no longer hold air. Depending on the severity of the leak, the tire may leak air slowly, or in more severe cases, not hold air at all, warranting replacement of the valve stem.
In most cases, the fastest way to replace a valve stem is to take it to a tire shop and have them remove the tire and replace the valve stem using the aid of a tire machine. However, for instances where this is not an option, a tire can be removed, and the valve stem changed manually.
Luckily for you, this blog post is going to teach you how to replace your old valve stem and keep your tires at their best!
Do Your Tires Need Them?
Have you ever gone to check your vehicle’s tire air pressure and found the cap that screws on the valve stem were missing on one or more tires? You may have thought you were lucky because you had easy access to the valve stem, thereby making it easier to add air to your tires. On the other hand, maybe you were worried and went to your local auto parts store to buy a replacement cap. Or maybe you didn’t think about it at all.
Everything on your vehicle that the manufacturer equipped serves a purpose, big or small. Something as small as a tire valve stem cap may seem insignificant, but it serves a pretty big purpose. The valve stem cap is not just a little plastic or metal cap to make the valve stem look nice. It is designed to protect the Schrader valve, a valve stem into which a valve stem core is threaded that keeps the air or nitrogen in your tires.
A valve stem cap is important for the Schrader valve because if one is not fitted, dirt and moisture can enter the inside of the valve stem, potentially jamming or contaminating the sealing surfaces and causing a leak.
Metal, and some higher quality hard-plastic valve stem caps, often have a rubber washer or seal inside to help make an airtight seal. This type of cap protects from dirt and moisture and helps prevent air from escaping from a slightly leaking Schrader valve. In addition, the rubber washer or seal prevents the cap from loosening and falling off due to vibrations by acting as a cushion between the cap and the valve stem. Most caps, however, are softer plastic designed for protection only and are not equipped with a separate seal.
Now, where might that little valve stem cap have gone? What probably happened was the last time you took your vehicle in for service, your tire pressure may have been checked, but the valve stem cap may not have been put back on. It is also possible that the vibrations created by the spinning of your tires over thousands of miles caused the cap(s) to become loose and fall off.
If your vehicle has a tire pressure monitoring system (TPMS), it is even more important to have a valve stem cap to keep the moisture and dirt out. Unfortunately, when the time comes to put your snow tires on or to replace your tires, you may have to replace your tire pressure monitor sensor if the valve core has seized into the stem, possibly making your wallet an extra $60.00-$80.00 lighter than you expected!
If you take your vehicle in for a routine service that includes checking the tire air pressure, the valve stem caps should be properly tightened and replaced if missing. If you find a mechanic who does this, you have found a keeper! Any mechanic who flags this issue as part of a used vehicle inspection understands how important it is to be thorough even when seemingly insignificant things.
What Can Go Wrong With Old Valve Stems?
Plenty: As they age more, valve stems could develop leaks, even if none now, resulting in premature wear, flats, or damage to a Tire Pressure Monitoring System.
Valve stems are not intended to last forever. UV rays from the sun, salt and age can result in cracks. Improperly replaced wheel covers may cut them. Scuffs against curbs or rocks also can damage them. Even a slow leak means that unless you repeatedly fill the leaky tire, pressure will dip, affecting handling and possibly leading to a tire-ruining flat. Low pressure can also result in uneven, premature wear, which will cost you money when you have to replace a tire much earlier than if it had been properly inflated.
How Can You Tell If a Valve Stem Is Bad?
Air up the tire and spray it down with soapy water. If there is an air leak, the bubbles will start to build up in one spot. Grab it with a pair of pliers and pull as hard as you possibly can until it comes out. Then, when you look at the backside of it, you’ll know if it’s bad.
Valve stem damage: New tires typically come with new valve stems because the old ones tend to wear out. If you have older valve stems, they may go bad over time due to use, dislocation, and exposure to chemicals on the road, such as road salt. As a result, they may rust and go bad.
Furthermore, what are the symptoms of bad piston rings? Piston rings eventually start to wear, and the seal between the piston and cylinder is no longer airtight. As a result, oil moves from the crankcase past the piston and into the firing chamber. Symptoms of this are white smoke coming from the tailpipe and a drop in engine oil level.
If a valve is bad, you’ll have a constant and very slow leak through the base or the valve body. The other possibility is that the wheel’s mounting surface where the bead of the tire seats has become damaged by corrosion or dented from hitting a pothole.
Are All Valve Stems the Same?
No, they are not. A rim with TPMS will have a different stem than a rim without one. The TPMS ones are usually compatible with the system, either a snap-in rubber version or sometimes an aluminium one. But don’t worry, you don’t have to go figuring out what’s the difference, because your mechanic will know which stem is right for your vehicle!
There are also metal and rubber stems. Metal stems aren’t necessarily better than rubber ones, but they are used a lot for appearance. For example, they’ll be a better match with your fancy chrome rims. However, it’s very important to remember that the stem has to be compatible with the valve. Since most metal stems are aluminium, you don’t want to use them with a brass valve! Aluminium and brass together result in a galvanic reaction that leads to corrosion and valve failure. So generally, aluminium stems are used with nickel-plated valves.
Not all stems are the same, and that goes for length as well. Stems come in different sizes to fit different needs. So, if you have wheel covers, you can use a valve stem that lets you check and refill your tire without taking the cover off. Aside from different valve stem lengths, they also make valve stem extenders, so if you’re not ready to change the whole thing, you can still adjust the length. However, you have to be careful with these, as they may not seal properly, and that can cause leaks, or worse, let water and dirt get into the core, corroding the valve.
What About Nitrogen and Nitrofill?
Nitrogen inflation requires better-sealing metal valve caps. These caps are usually silver and have a green top with an N or N2 (for nitrogen, obviously). They usually look more like a screw nut than a cap. Since Nitrogen fill is generally pricier than air, you want to make sure it lasts, so it’s a good idea to check these stems regularly. If you do use nitrogen regularly, avoid topping up the tire pressure with regular air. It doesn’t cause any crazy reactions or harm, but it does end up defeating the purpose of using nitrogen by cancelling out all the advantages.
How to Replace a Valve Stem?
Step 1: Loosen the lug nuts. Loosen the lug nuts of the wheel from which the valve stem is going to be replaced.
Step 2: Raise the car on jack stands. Set the parking brake, and then raise the vehicle and secure it on jack stands.
Step 3: Remove the wheel. Once the vehicle is raised, remove the wheel and set it flat on the ground with the outside of the wheel facing up.
Step 4: Deflate the tire. Remove the cap from the valve stem, and then remove the valve stem core using the valve stem removal tool to release the air from the wheel.
Once the valve stem core is removed, the tire should deflate on its own.
Step 5: Separate the tire’s bead from the wheel. Next, use the sledgehammer to break the tire’s bead free from the wheel.
Hit the sidewall of the tire using the sledgehammer in the same place until the bead breaks loose.
When the bead breaks loose, you may hear a crack or popping sound, and you will see the inside lip of the tire visibly separate from the lip of the wheel.
Once the bead has been broken, continue around the tire with the sledgehammer until the bead is completely broken around the tire.
Step 6: Lift the lip of the tire from the wheel. Once the tire’s bead has been broken, insert your tire iron between the edge of the rim and the inside lip of the tire, and then pry upward to pull the lip of the tire over the edge of the wheel.
Once you have pulled the lip of the tire over the edge of the wheel, work the tire iron around the rim until the entire lip of the tire is off the rim.
Step 7: Remove the tire. Grab the tire by its removed lip and pull it upward so that the opposite lip at the bottom of the wheel is now touching the top edge of the rim.
Insert the tire iron in between the tire’s lip and the edge of the wheel and pry upwards to pull the lip over the edge of the rim.
Once the lip is over the edge of the rim, work the tire iron around the edge of the wheel until the tire is removed from the wheel.
Step 8: Remove the valve stem. Once the tire is removed from the wheel, remove the valve stem. Then, use the needle-nose pliers to pull the valve stem free from the wheel.
Step 9: Install the new valve stem. Take your replacement valve stem and install it from the inside of the wheel. Once it is in position, use the needle-nose pliers to pull it through into place.
Step 10: Reinstall the tire. Reinstall the tire onto the wheel by pressing it down over the rim until the bottom bead clears the edge of the rim.
Then press the side of the tire down underneath the edge of the wheel, tuck your tire iron in between the lip of the wheel and the bead, and then pry the bead over the lip of the wheel.
Once the bead clears the lip of the wheel, work your way around the entire wheel until the tire is completely installed on the wheel.
Step 11: Inflate the tire. Once the tire has been reinstalled onto the wheel, turn on the air compressor and inflate the tire to the correct specification.
The recommended pressure is between 32-35 pounds per square inch (psi) for most tires.
Step 12: Check for leaks. Once the tire is properly inflated, double-check to make sure that there are no leaks of any kind, and then reinstall the tire onto the vehicle and lower it off of the jack stands.
For most cases, the easiest course of action to replace a valve stem would be to take it to a tire shop, have the tire removed with a machine, and then have the valve replaced.
However, if that is not an option, a valve stem, and even a tire, can be removed and replaced manually with the correct tools and the correct procedure. If you find a leak or damage in the tire and not just the valve stem, you may want to replace the tire entirely.
Tire Valve Stem FAQs
What to Know About Replacing Tire Valve Stems?
Get the Right Tools
Before you start replacing anything, make sure you have the right tools. For example, when you pick up your new valve stem, you’ll also need to get a replacement valve core and valve stem tool.
A valve stem tool looks like a plus sign.
Test the Valve Stem for a Leak
Before changing your valve stem, verify that it’s leaking first. For example, you can test for a leak if you take some water and a blob of dish soap together and rub it over the uncapped valve stem.
The valve stem is leaking if there are little bubbles that form at the base of the stem.
If no bubbles form, then your valve stem is likely not the culprit of the leak.
Replace the Stem
Once you’ve verified that the valve stem is leaking, you’ll need to let the air out of the tire after you’ve removed it. Next, you’ll need to unscrew the valve from the tire using the valve stem tool you purchased earlier.
The valve core will be pressurized if any air is left in the tire, so be sure to remove all the air before removing the core. Once you’ve taken out the core, throw it away, and you’re ready for the next step.
Clean the Valve Stem
The valve core tool you purchased is needed to clean the inside of the valve stem. Clean the opening in the tire where the valve stem came from, and ensure it’s clean from dirt and debris.
Install a New Valve Stem
Now that you’ve prepared your tire with your new valve stem and it’s clean grab your valve stem toll. Using the same end of your valve stem tool, install the new valve core. Tighten your new valve, making sure there are no leaks.
When your new valve is on tight, put air back into your tire and add the valve cap back on. Just like that, and you’ve replaced your valve stem on your own!
Replacing Valve Stems on Your Own
As you can see, it requires several simple steps to complete a valve stem replacement on your own. However, by doing this, you’ll save money and time. From finish to start, it should take less than 10 minutes.
How Long Do Tire Valve Stems Last?
Since rubber deteriorates over time and tire valves are not expected to resist deterioration for the life of two standard tires in normal service, tire valves should be inspected and replaced if any cracking appears. As a rule of thumb, the industry recommends replacing tire valves whenever new tires are installed.
While Track & Competition DOT tires may only last several weekends on your track driven racecar, the metal clamp-in tire valves should be replaced every other year because the heat transmitted to the wheels from the brakes is significantly greater than that experienced in normal service.
Special metal clamp-in or rubber snap-in valves are also used to anchor the sensor/transmitters used by the many direct tire pressure monitoring systems (TPMS). These unique metal clamp-in valves feature a threaded insert in their base to accept the bolt that attaches the sensor/transmitter to the valve.
How Can You Tell If a Valve Stem Is Bad?
First, you need to determine if your valve stem is leaking or not. You can do this by rubbing a mixture of dish soap and water over the uncapped valve stem with your finger. If bubbles begin to form it means air is escaping and the valve is leaking.