The airbag suspension is different from the standard airbag you are probably thinking of right now, which is the safety airbag.
The suspension airbag provides your semi-truck with a more comfortable and safer drive since it improves the carrying performance.
Thus, it is vital always to ensure you replace it regularly to maintain good condition. In this article, we will teach you how you can do it.
A Short Answer on How to Change Cab Airbags on a Semi-truck:
To change the suspension cab airbags of a semi-truck, remove the old ones first by disconnecting them from the airlines. Remember to drain the air inside. Then, install the new airbag the same way you remove the old one. Once done, start the semi-truck and allow the airbag to fill.
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What are Cab Airbags, and How Do They Work?
Cab airbags or airbag suspension improves the load-carrying performance of your semi-truck.
It provides better braking, handling, and steering to ease maneuverability and safe driving.
Airbag suspension works like a balloon. Its design makes it withstand the weight of your semi-truck frame.
You can experience several benefits if you have a good quality cab airbag installed on your semi-truck.
With proper usage, the airbag suspension can lessen the chances of your semi-truck wearing out. Thus, you may also have lower maintenance costs.
When Should Cab Airbags be Replaced?
Keeping up with the condition of the cab airbags will help you decide if it is time to replace them.
On average, an airbag suspension can last for about 50,000 to 70,000 miles or is equivalent to 10 years of usage, depending on the manufacturer.
However, there are certain signs you should always check to know if it is better to replace the airbag suspension already.
Here’s a checklist:
- The air pump often turns on and off, an indication of leakage
- The semi-truck already sags on only one side
- The air pump runs while the semi-truck is still operating.
- You need to pump the airbags first before you can drive your semi-truck
- You already feel a soft sensation in the suspension whenever you are inside the cab.
- It is hard to adjust the seat height to your liking.
How to Change Cab Airbag on Freightliner?
Freightliner is the most popular semi-truck brand, particularly the Freightliner Cascadia. Thus, we will cover the steps in changing the cab airbag for Freightliner Cascadia.
Freightliner trucks have two cab airbags, so you must repeat the installation steps twice. Here’s how you can do it:
1. Use a jack to lift the cab.
2. Once lifted, start releasing the airline from its fitting using a one-quarter wrench.
3. To remove the air line fitting, press it down to detach it from the airbag.
4. Get the new airbag and prepare it for installation.
5. Connect the new airbag to the airline with a similar method to release it.
6. Once you get the airline, give it a little pull to ensure it will lock.
7. After locking the airline, bring the airbag down and clip it into the hole you can find on the top.
8. Once you secure the airbag in its place, you may now proceed to the other airbag by repeating the above steps.
9. After installing the two new airbags, bring down the jack to allow the airbags to inflate.
How to Change Cab Airbag on Kenworth?
Changing a cab airbag on a Kenworth truck is almost similar to Freightliner.
However, some Freightliners may not need to drain the air out of the old airbag, which is the initial step when doing it for Kenworth trucks.
Here’s how you can do it:
1. First, shut off the air suspension or drain the air from the old airbag for about five minutes.
2. Take the airlines off the airbag by loosening the nuts using a wrench.
3. Ensure you remember the actual arrangements of the lines before you take them off to avoid misplacing them once you install the new airbag.
4. Remove the bolt from the bottom using a three-quarter wrench. You may use a ball socket or two wrenches together as an alternative.
5. Remove the two top bolts using a 9/16 socket to finally take the old airbag out.
6. Get the new airbag and install it by putting the bolt below first.
7. Next, put the bolts on the top to line the airbag in its place.
8. Pull the top of the airbag back up and ensure it stays on its line.
9. Tighten all the bolts.
10. You may also apply a sealant on the airline as you connect it with the airbag to prevent leakage.
11. Wait for 10 to 15 minutes before turning on the semi-truck.
How to Change Cab Airbag on Peterbilt?
Almost every truck brands have similar ways how you can change the cab airbag suspension.
But what makes the Peterbilt unique is that you can replace its airbag suspension using only two tools, namely pliers and vise grips.
Here’s how you can do it:
1. Take a pocket screwdriver and pull the little tab out.
2. Push the tab down, so you can raise the cab.
3. Use cribbing to hold the cab up and remove the airbag.
4. Squeeze the bag to see if it still has pressure and remove the airline.
5. Get a pair of vise grips and clamp the line off. Be careful, as the vise grips can slip.
6. The top and bottom parts should have clips to squeeze them. That way, you can drain the remaining air inside.
7. Once you release the air, you can remove the old airbag.
8. Get a new airbag. Snap it on the bottom and work the top into the hole until it is locked.
9. Start your semi-truck to build the pressure and raise the cab. Pushing down will cause air to raise the other cab airbag.
10. Slip the vise grip off from the airline. It is better to deflate the airbags before releasing the vise grips and then air it back up.
11. Repeat all the above procedures for the other airbag.
How to Change Cab Airbag on Volvo?
Changing the cab airbag of your Volvo truck is also an easy thing you can do by yourself, helping you save up from costly repairs.
Here’s how you can do it:
1. Get on pliers that fit well to the nuts and bolts attached to the airline.
2. In some Volvo trucks, you may find a knot inside, so you may need to weld it or cut the part out using a wrench.
3. Then, unscrew the knot and eject the cab up. Put a jack to secure it in that position.
4. Remove the airline and the airbag.
5. Get the new one and stick it underneath. You can thread it using your hands and stick it on the bottom.
6. Quickly connect the airlines, and you’re all set.
How to Replace the Cab Airbag on an International?
Compared to the other four popular trucks mentioned here, you may find replacing the cab airbag on an International truck more complicated.
Don’t worry, though, as we still got you covered.
The first you should know is that the International truck cab airbag comes with a shock absorber. Thus, it would be best if you replaced both airbags regardless of whether it is still in good condition.
Here’s how to do it:
1. Remove the levering valve held by only two bolts to give you space to remove the four nuts below the airbag or the brackets that hold the shock absorber.
2. Remove the nuts and bolts below the airbag or the one with an attached safety mechanism.
3. Raise the cab on both sides using a regular carjack or use alternatives like wood or bricks.
4. Remove the airbag by pushing the washer up using your hand, then pull until it comes off.
5. Put the new airbag on the same way you removed it.
How to Get the Most Out of Your Cab Airbags?
If you want to make the most of your semi-truck cab airbag, there are several factors you need to consider.
First, consider using air springs as they can withstand weight better than the two-ply rubber and support wires. Thus, boosting the hauling and towing performance of your semi-truck.
You should also adjust at each corner of the cab, even weight distribution.
Your truck’s gross vehicle weight rating or GVWR still applies to provide the airbags with better support and handling, so you should also pay attention to its rating. That way, you can stay within the load limits.