vtraudt

Any good tips how to remove rusted-in solid ABS sensor (here: rear)?
Done:
- soak, soak, soak again in PBBlaster
- Rotate/wiggle plastic head back/forth. Soak again.
- Rotate/pull. Soak.
- Chisel, hammer, pull

Typical ends with head breaking off.

Then break up interior pieces until all is removed, but the alu exterior shell of sensor rusted solid to the (copper?) 'cage'.

Best way to drill out that cage?

OD of sensor appears to be 16mm (did not write down exact dimension).

Old_School_Audi

There is a high probability it's ruined if any twisting occurs on the electrical connection relative to the sensor body in the wheel bearing housing (wbh). At this point brute force is required, just don't damage the tone ring on the outer CV joint. If you can get the joint out of the bearing, then just drive it through with a punch or drill if neccessary.

Once you have removed it, clean the bore in the wbh with a brake cyl hone or fashion something to abrasively clean the rust out of the bore. It's the rust from the wbh bore that creates the seizing. The sensor body is stainless.

Before installing the new sensor clip and ABS sensor, coat the bore with antiseize.

FWIW: at 70°F a sensor should ohm out somewhere around 1700µ ± 300µ

vtraudt

Sensor is trash, 90% of pieces removed. Rest appears to be outer skin of sensor bonded to the 'cage'.

Recommendation for drill size?

Don't want to remove the drive shafts (both rears); hope drilling somewhat undersized will brake up the 'skin' and 'cage'.
What is the bore diamter?
Where to get a 'cage' from (sensors don't come with new cage).

4Driver4

Remove the shafts and clean the old sensors out with a punch. Drilling will introduce tons of metal filings and may damage the tone ring.

vtraudt

Darn. Will take shafts off then.

Punch will not work (like a I said, there are only thin wall pieces left; can't even get with a screwdriver to unlodge those). But will remember for next time (for breaking up the stuck sensor into small pieces for removal) and try to out through (maybe it then comes out complete in one piece).

Old_School_Audi

Haldex/Midland part # = A59512309

These are available from NAPA.