fastduck

Finally opened up the flex-plate inspection cover to measure crank end-play, verify released flex plate ("PO just did"), O2 snsr., etc. THIS IS WHAT I FOUND!
What is it? I'd guess that it's a, if not "the" Hall sensor and the magnet is the bent little piece which has scraped a nice groove in the bell housing as well as grinding away at the "sensor".

Suggestions? The car has been running "ok" since I bought it, but I'm afraid that the bent little piece will snap off if I try to bend it back straight against the flexplate.

Sorry if the photos aren't great, don't have a great camera. The second photo showing the sensor is looking up to the top of the bellhousing.

Thanks very much

John
"fastduck"
'88 S4 auto (obviously)

Lizard928

It is a top dead center pin for use with a special VW tool.

It has not been used in years, not do I see any use for it in the future.

You can just leave it the way it is. It is obvious the other one broke off already.

Bertrand Daoust

I don't know what is it but I'm quite sure it is not the hall sensor.
The hall sensor is, if I remember well, on the other side of the flex plate.
Correct me if I'm wrong.

jcorenman

The hall sensor is on the backside of the passanger-side timing-belt sprocket.

As Colin said, that pin (and it's missing mate) and the magnetic sensor in the second picture are for a long-disused diagnostic tool. (The other end of that sensor is the unused connector on the drivers-side of the intake, just aft of the bellcrank assembly).

How's the end-play?

P.S. The pictures are great! Good use of natural light, could be color-corrected but no big deal. Much better than a thousand words like "what's the bent dingus on the flywheel?"...

Bertrand Daoust

Thanks Jim for clarifying.
My mistake.
I was thinking about the crank position sensor.

fastduck

Thank you both. At least it's only a sign of poor mechanical treatment in the past, which I'm constantly finding, and not yet another thing that I need to worry about or buy.
Can't say for sure about the end-play; I can't yet figure out a good way to lever the flywheel towards the front, but my dial indicator showed .006" when I pulled it to the rear. I need to cobble up a smaller prybar, I have only a big crow, and the car is up on jack stands so not a bunch of clearance.
The flexplate moved only .020" so that's a good sign of something? Replacing front and rear clamp bolts anyway.

Thanks again,
John