E39 M5 Brake Lines
Two Sundays ago I was driving home from the final club DIY event of the year. I had done a simple oil and filter change on my 2002 E39 M5 (at 118,100 miles) and inspected the car while on a lift to research future projects. There were a couple of things that needed attending to, but nothing urgent. That changed on the drive home.
About 15 minutes into the trip, I noticed the brake pedal feeling spongy. It was a gradual kind of realization, nothing too dramatic or scary. But then the Check Brake Fluid warning flashed on the display. I managed to get home by driving very cautiously. I had some brake fluid left over from the M3 job last month to use for the M5.
When I checked the brake fluid reservoir it was well below the minimum line. I refilled it, and while it didn’t all leak out the line went down. A small amount of liquid was also dripping from the bottom of the car. Why couldn’t this have happened a few hours previously, when I was in a position to do something about it? DIY karma was not with me this time.
I had no choice but to bring the car to my local shop, Craftsman Auto in Alexandria. It’s a good shop and has done work for me before. But I much prefer knowing exactly what job I’m asking them to do, like when the alternator went out on my M3. In this case, I was sharing the unease felt by millions of Americans when they hand over their vehicles and say, “Please tell me what’s wrong and fix it.”
The diagnosis was that the brake lines were leaking. Timing was against me as well – I wasn’t able to bring the car in until the day before Thanksgiving. Unfortunately, there was some initial confusion about which parts to order, so my car had to stay in the shop until Friday. Then the job was completed. My E39 M5 brake lines are now all new, two from the ABS unit and one to each wheel. The brake fluid is new as well, so I don’t have to worry about that job for at least two years.
I wish this were a job I could have diagnosed and tackled. I would have saved money and stress. Here’s a how-to video from the popular DIY channel Yevs Builds. OTOH, I’m fortunate to have a shop I can trust in Craftsman. Things are going to happen with a car over 23 years old, no matter what kind of preventative maintenance I give it. I’ve owned two older M cars for many years now, and there have not been many unpleasant surprises.
Let’s hope that continues into 2026. Happy holiday season!
