I may be screwed, but maybe someone has a solution for me. 1998 A4 Quattro 2.8.

I finally got my tools together to do the rear bearing replacement, which went fine, but while removing the knuckles I could not get the ABS sensors to free up. I probably broke the sensor because I first thought it twisted out and the plastic head moved but the steel part sticking in didn't. Or, I noticed that someone before me just cut the wires and spliced them back together, which must of worked, so on the other side instead of taking a chance I did the same. In the end I just cut the wires and spliced them back together.

I don't know if the problem is I broke the left one by trying to turn it out, or the splicing job didn't work. Anyhow, I get the yellow ABS light and blinking brake light on the dash. New sensors are $170 each, more than I can afford for a while, are there any other options for me?

 

Unfortunately, they often fail when you attempt to remove them. I wouldn't splice the wires; they will be prone to corrosion and failure. You can try getting some used from Shokan Coach Works in NY if you need them.

For now, you can pull the ABS and ESP fuses to prevent the system from throwing a hissy fit every time you brake.

 

I found an aftermarket sensor on ebay for $60 shipped, so I thought I would give it a try since the alternative right now was watching the brake light blink and not have abs. It arrived, the cord was an inch longer and I had to modify the rubber seal where the wire goes into the body, installed it and everything worked great. The lights on the dash went out, test drove it in some loose gravel, worked great.

But there is still a problem. When I stop on dry pavement, the brakes still pulse at the very end of the stop. The wheels are not slipping, but the abs think they are, it's annoying, but doesn't affect the braking. Is there a step I missed? Does something need to be calibrated? Or is the problem just my cheap Chineese made sensor? BTW, it was the left rear I replaced.

Thanks for any advice.

 

Most likely. If any one sensor is reading slightly different than the others indicating impending lock-up, the ABS will activate. Check the tone rings on the axle for dirt or rust and try cleaning them if you see signs of either.

 

Tweaked, thanks for your help. I was able to inpect the tone rings when I replaced the bearings, so there shouldn't be any dirt in there, but they were rusty looking. I suppose it is possible they could of picked up some grease or something from the knuckle when I reassembled them. Could I just try to squirt some brake cleaner in there and wash it out from the inside?

 

It can't hurt. You could try compressed air as well. If you have a VAGcom, I believe there is a block that shows you the wheel speed sensor signals. Comparing them could pin point the problem sensor or wheel (though we know it's likely the new sensor).

 

Can you find out where to measure exactly that? Thanks!