My Excursion seems to have an issue with the ABS engaging while driving slowly. It sometimes sounds like it engages continuously every 10 seconds, even when I’m not using the brakes, especially when cruising on a gravel road at about 5 mph. When I’m driving normally and approaching a stop, I feel a kickback from the ABS around 5 mph, accompanied by a groaning sound. The brakes have also felt a bit spongy since this started, so I suspect there’s air in the system. I bought an Autel scanner specifically for bleeding the ABS manifold, which provides temporary relief, but the issue returns after driving about five miles. Unplugging the front wheel sensors makes the problem go away, but that triggers the ABS light, leaving me with no ABS function. I’ve been managing it this way, but any assistance would be appreciated. Could air in a caliper be the cause? I wonder if I didn’t bleed it well enough during a recent brake job. Should I keep bleeding the ABS? I’ve done it about eight times already.
TL;DR: The ABS engages at slow speeds. I’ve bled it about eight times, but the fix only lasts a short while.
It is likely a front ABS sensor. My '04 F350 had the same issue the right front sensor read 0 while the others were at 5, causing the ABS to try to match them. You will need a tool to monitor the speed, or if it is the front, you can let go of the steering wheel to see which way it pulls. If it pulls to the left, then the right front sensor or hub is likely bad.
It does turn to the left. And it is only been a left hub for 1.5 years. Among the things I have not replaced in the ten years that I have owned the vehicle is the right hub assembly. I will investigate that as well. I wish I had the means to make an accurate diagnosis.
The right front hub is the cause if it pulls to the left. After 15 years with no problems, I replaced my together, and two years later, a fresh one began to do that. It was resolved when I installed a new sensor. Chevys with only one side replaced are extremely prevalent. Since 50% of the time, replacing just one Silverado hub can result in a false activation of the ABS, I always replace them all at once.
You may graph all of the abs speed sensors and compare which is losing out first, depending on the capabilities of your scanner. Next, focus on that tone ring or sensor.
Alternatively, you can keep an eye on the isolation valves of your abs to determine which one is operating during the event and focus on that wheel.
When it occurs, does the speedo needle jump as well?
There is nothing wrong with the speedometer needle. Unfortunately, cost was a concern when I bought the scanner I had to replace the exhaust manifolds, rear-end clutch packs, and new shocks, which had my wife a bit anxious about our spending . So it doesn’t have those features. I am still within the return window, do you have any suggestions? I keep hearing about Forscan on forums, but I assumed it would be too pricey.
No, it started about a year ago during a hunting trip while driving on rough gravel roads (I’m not sure if that triggered it or not). I am currently working on the clutch packs. I disassembled everything last night after finishing the exhaust manifold replacement, and I’m reassembling today. Is there anything specific I should check on the tone ring, like dings or dents? If it is compromised, can I just lightly sand it down, or would it need to be replaced? I’m a self-taught DIY mechanic.
Not that I have discovered, but I haven’t looked closely yet either. All the ring and pinion gears seem to be in good shape, and the bearings and races look fine at least based on my limited knowledge. This is my first time working on a rear end aside from draining and replacing fluids. I think I will need to create a new post with pictures for better feedback, but I’ll definitely do that.
. So it doesn’t have those features. I am still within the return window, do you have any suggestions? I keep hearing about Forscan on forums, but I assumed it would be too pricey.