Troubleshooting: What Part of The C5 Suspension is Failing?
The Audi Allroad Quattro is a dynamic car with the space and cargo of a station wagon but the off roading capabilities that have been compared to the Jeep. While the 2001-2005 Audi C5 is still sought after for its diverse performance features, a common issue with the Allroad C5 is the body dropping and refusing to maintain ride height adjustment features or lift into Jack Mode. When you see signs of failing suspension, the first thing you must do is find the source of the problem.
The Allroad C5 uses an Adaptive Air Suspension system with height sensors in all four corners. You will have electrical components to inspect as well as air supply systems to consider when working on the C5’s suspension. To make these complex systems a little easier, these are some of the basic guidelines to the common issues found in this type of air suspension system.
- Listen to the air compressor. If it whines, grinds, or clicks the chances are the motor or fan has gone bad and will need to be replaced. Once replaced you can troubleshoot the air springs and struts to make sure they are holding air pressure.
- If the compressor doesn’t run at all you will have to check for a blown fuse and bad electrical connections. Replace wires that look distressed and make sure connectors have solid contact. This would also be a good time to check level sensors to make sure they haven’t been bent which will provide the suspension with false readings. If the electrical components all come back as okay and the compressor still isn’t running, it’s time to replace it.
- If the air compressor is running fine, your next area of troubleshooting is the air lines and bellows. You can use soapy water in a spray bottle to follow the air lines from the compressor to the wheel well, including the front air struts and rear air spring bellows. Bubbles will form wherever there is a leak and you will know which part needs to be replaced.
If you are finding several air leaks, replacing air lines and springs or struts in all corners of the vehicle will maintain a steady level of air pressure throughout the entire suspension system.
Replacing Front Air Struts
Because the Allroad C5 has such a dynamic air suspension system, a common issue is the air struts losing air overnight which makes one side or the other have a noticeable height difference. If the front end is experiencing the problem then the 4-level air suspension won’t be able to keep up and the rear will rise while the front points downwards, risking nose dives. Replacing the front struts will help your Allroad C5 lift faster when changing air levels and will improve your steer handling for better ride control.
The Allroad C5 is considered relatively easy to work on, and this video gives you step by step instructions on how to take out your old front air struts and how to install replacements. The list below is some tips to keep in mind as well as the tools you’ll need to follow the installation video.
Replacing Rear Air Struts
Like the front suspension, when the rear struts fail to remain inflated the back end will drop. Not only does this cause the back end to scrape and bottom out, but the Allroad C5 loses its independent self-leveling feature resulting in horribly bumpy rides and an inability to do any light loading or towing, which is exactly what the C5 was built for.
To get your rear end back up to its original ride height and load leveling capacity you’ll need to change out your rear air struts. This video will guide you through the process to make rear strut replacement easy for you. Remember to be gentle with the collets on the air lines and the level sensors on the control arms. Here are some additional tips on the rear air struts and the tools you will need to prepare your work space.
Replacing the Air Compressor
If the air compressor is overworked from age or faulty spring assemblies, or doesn’t run at all, you will need to replace it to maintain the Allroad C5’s air suspension.
Before jumping into the air compressor installation at home, watch this step by step installation video. If you need to buy a new compressor be sure to find a direct replacement part that includes a relay. Without the relay you will not be able to utilize the Jack Lift Mode and you will not be able to drop your suspension when you need more grip on the road. A great replacement part is Suncore’s C5 Air Ride Suspension Air Compressor with Dryer for the Audi Allroad Quattro, the parts are linked at the bottom of this page for reference.