It all started while off-roading in 4-low a couple years ago. The symptoms were that the anti-lock brakes would kick on when I stepped on the gas from a dead stop. Irritating but I ignored it since it only happened on the trail.

Lately it's been happening on the street in 2 wheel drive. I removed the front two speed sensors a couple weeks ago and cleaned all the rusty particles off. Mostly driver's side. No improvement. Very challenging to get them out.

Today I pulled all 4. The fronts were easy to remove since I just did them. The driver's side was covered again in rusty dust. I could see plenty more rusty dust between the teeth in the hole as I spun the caliper. The o-rings were barely holding together and pretty crunchy. It also seemed that a ring of the plastic under the o-ring was still inside the hole on both of them.

The rears were harder to get off. The first thing I noticed was plenty of grease in the back on both sides. (There was no grease in the front ones)

I wiped each down and reinstalled. Started it for a test drive and now the Brake and ABS lights are on (along with VSC and the TRAC lights that always come on when something is wrong.)

My questions are:
1. Should there be grease in the fronts?
2. Did I likely damage one or more sensors trying to remove them, causing the ABS and Brake lights to come on?
3. Any steps I should take to reset the system?
4. Should I just replace all 4 sensors? If so, OEM or other?
5. How should I deal with all the rusty crap inside the teeth in the drivers side front?

TIA!

You might have kinked the copper wire inside the rubber tube of the sensor or stretched em. Check the resistance to be sure.The face of the sensor should be clean of debris. If there is debris on the reluctor ring that can cause issues so clean it. brake cleaner with a thin tube rotate the ring while cleaning it. Grease is applied around the o-ring. check the abs codes may point you to the one thats causing the issue. Take it to a auto parts store or jumper the abs code module as per the fsm. Folks who don't like the abs or while off'road pull the abs fuse which is bolted, so the fuse box has to be lifted. Also there are threads to disable abs.
ABS/VSC/TRAC Disable Master Thread
Some might suggest zero point calibration but in my opinion the system goes back to normal if the abs issue is resolved. Good'luck.