If you’re having BMW 740Li suspension problems, you’re probably looking for the right way to fix them. While there are a few ways to solve air ride issues, some are far more costly and time-consuming than others. In this article, we explore how your air suspension system works, what its most common issues are, and how to fix those problems.
Using a Strutmasters conversion kit to replace your BMW 740Li air suspension with a passive suspension can cost thousands of dollars less than repairing it at the dealership. For just $1599 you can replace your entire air ride with a sturdier, more reliable coilover system.
About the BMW 740Li Air Suspension
The BMW 740Li features an active air suspension system. This system uses air springs—rubber air sacs—provide the damping effect and keep the car at the proper ride height. The air pressure inside these air springs is adjustable, allowing the system to adapt to changes in the road surface.
Here’s how the air suspension on your 740Li works:
- Ride height sensors take a constant reading of the body of the car relative to the wheel and axle. The sensors transmit this information to a suspension computer called an electronic control unit (ECU), or electronic control module.
- The ECU processes the readings and instructs the compressor to generate the amount of air needed to inflate the springs to the proper ride height.
- A suspension air compressor generates pressurized air and pumps it into the air tank.
- As air is being pumped into the tank, the tank releases the air needed to inflate the springs into the manifold.
- The manifold distributes the air as needed through flexible hoses and into the air springs.
- Each air spring inflates, or deflates, to adjust for changes in the road.
This may sound like a long process, but it happens almost instantly and constantly. As you can imagine, this system requires a lot of precision and for all components to be working properly at all times.
Common BMW 740Li Suspension Problems
Unfortunately, the BMW 740Li is one of many vehicles that suffers problems with its air suspension. Air suspensions are composed of computers, moving parts, flexible materials, small gaskets, and other parts that are prone to wearing out or being damaged. That means that the system has a limited lifespan.
Such a complex system with so many components means that there could be many different problems. But with the BMW 740Li, some air ride issues are more common than others. Some of the most frequently-mentioned air suspension problems for this model include:
- Leaking air spring: Made of a flexible rubber, air springs in the 740Li are vulnerable to getting punctures, cracks, or dry rot. Any of these types of damage can cause air leaks, which cause the air compressor to overwork and can lead to early failure.
- Rear suspension going out: Some BMW 740Li owners have reported that their rear air suspension stops working at random intervals. This can make the car difficult to handle and can affect its stopping distance.
- ECU fault: The ECU that controls the air suspension system has also been known to have issues such as electrical faults. A faulty control module can cause total system failure.
- Leaking air lines: Road debris, gravel, or other foreign objects can sometimes scratch or puncture the hoses that deliver the air to the springs. Similar to a leak in the spring itself, this can cause the compressor to overwork to compensate.
BMW 740Li Suspension Failure: Early Warning Signs
Your BMW comes equipped with a sophisticated diagnostic system that can detect faults in the air suspension. When it does, it will display a warning light to bring it to your attention.
However, this system may not notice air ride issues until they’ve become big enough to register. There are some signs that you can observe that may indicate a problem with your 740Li’s air suspension before your diagnostics pick up on it. These include:
- Compressor noise: The suspension compressor in your BMW 740Li should run very quietly. If you hear it running loudly, this is a sign that it is overworking and there may be a leak in the system.
- Sagging or leaning appearance: If you notice that your car is leaning to one side or corner, there’s a good chance that the shocks and struts are not functioning properly. In the 740Li, this happens most often with the rear of the vehicle, but it could happen at any wheel.
- Nose diving: When you bring your BMW to a stop, the suspension should distribute the force of that stop evenly. If the front of your car dips down while the rear lifts up when coming to a stop, this is a sign that the front suspension is worn down or has a problem.
- Long stopping: If you know that the brakes in your car are in good shape but it takes an excessive amount of time and distance to stop, it may be due to suspension problems. The suspension is what absorbs much of the force of stopping a car, and when it is worn out or broken it can no longer do this properly.
- Bouncy ride: BMW designed its air suspension system to provide a super smooth ride that feels like it floats over the road. If you’re feeling a lot of bumps and divots in the road, the suspension is not working as designed.
How to Check For Suspension Problems on Your BMW 740Li
There is also a very easy way to actively check for problems with your air suspension known as the bounce test. To perform the test, push down on each corner of the vehicle as hard as you can. Then, wait for it to get back to its resting height.
When the air spring is in good shape, the body will pop back into place right away and settle immediately. If the corner takes a while to get back in place or bounces up and down a few times before settling, there is likely a problem at that corner.
Passing the bounce test doesn’t mean that your BMW 740Li doesn’t have any issues. However, failing the test is a solid indicator that there is a problem of some kind.
How to Fix BMW 740Li Suspension Problems
Suspension issues can make your BMW annoying, difficult, and even dangerous to drive. Ignoring them can cause those issues to affect other parts of your vehicle such as the steering and brakes.
For these reasons, it’s vitally important to attend to suspension problems in your 740Li as soon as you notice them. There are a few approaches you can take to fixing your air suspension.
Fix Your BMW 740Li Air Suspension at the Dealership
Many people’s first instinct is to take their car straight to the BMW dealership. If you’ve done this, you probably got a shockingly expensive repair estimate. Getting any work done on a BMW can be pricey, but air suspensions are costly to fix on any car.
According to data from RepairPal, the average cost to replace just one air spring on a BMW 740Li is around $2,500, including labor. That means you could spend nearly $10,000 to replace all four, which you’ll likely need to do.
While labor at a BMW dealership is expensive, the parts themselves make up the bulk of the cost. RepairPal estimates that the original equipment manufacturer (OEM) air spring components cost around $2,100.
But, importantly, that labor is still very expensive. That’s because the complexity of air suspensions means that technicians need more time to work on it. Even if you can save money by buying second-hand or aftermarket air suspension components, you’ll still have to pay several hundred dollars to have them installed.
Convert Your BMW 740Li Suspension
There is another option for your 7-series that you may not be aware of. Instead of dealing with endless air suspension repairs, you can get rid of your air ride altogether and replace it with a simpler, more robust passive coil suspension.
This BMW 740Li air suspension conversion kit from Strutmasters comes with everything you need to completely replace your faulty air suspension. For less than you’d pay to replace just one OEM air strut, you can fix your entire suspension.
With your new suspension, your car will be seated on steel coil springs instead of air bags. No computers, no compressors, no manifold—just old-fashioned, time-tested mechanical resistance.
The engineers at Strutmasters also designed these kits to be fast and easy to install. Many customers choose to do the installation themselves, as it only takes about one hour per wheel for a reasonably handy person with a few tools and a sturdy jack. Even if you have a mechanic do the conversion, you’ll still save a substantial amount on labor fees.
Strutmasters BMW 740Li Air Suspension Conversion Kits: The Affordable, High-Quality Solution
You can spend thousands trying to keep your 740Li air suspension alive if you’d like. Or, you could spend a fraction of that one time to end your BMW air suspension issues forever. When you consider not only how much money you can save, but time, energy, and worry as well, it’s clear that the Strutmasters air suspension conversion kit for the BMW 740Li is the best way to fix your air ride problems.
With more than two decades of experience in the industry, Strutmasters knows how to design and produce kits that perform and stand the test of time. When you decide to convert your BMW 740Li air suspension with a kit from Strutmasters, you can count on the following:
- Premium materials: Our products start with the best materials for the job. We insist on using only premium metals and other materials to ensure maximum strength and durability.
- Precision engineering: We design each component in our kits to be a perfect fit for its vehicle, testing and redesigning as needed until we get it exactly right.
- Manufacturing excellence: Each component we offer is made in factories here in the U.S.A. This allows our quality control team to make sure all manufacturing meets our rigorous standards.
- Product guarantee: All of our kits and components include a one-year limited warranty to demonstrate our trust in our products and pass that sense of trust on to you.
- Expert support: Our people know suspensions and they’re here to help. Whether it’s finding the right part, answering a few questions, or helping walk you through an install, we’re happy to offer our full support.
Purchase your BMW 740Li air suspension conversion kit online to finally bring an end to your air ride issues. If you have any questions or want help making sure you get the correct part, contact our customer support either by phone at 844-712-0634 or by using our chat feature on the right-hand side of your screen.