Reference sensor bolt

[Geoman]

Just removed both the reference and speed sensor bolts and on the reference sensor bolt there is a nut that is firmly in place, certainly doesn't move by hand. Is the nut suppose to move or does it act to position the bolt at a certain level...or something else??

[thomasryan]

should be 6x24 so see if something has snapped off in the bracket that bottoms out the proper bolt.

[Geoman]

I was wondering, if the two bolts are suppose to be the same, then some PO might have substituted a regular 6mm hex bolt for the original shoulder bolt and the nut was suppose to take the place of the "shoulder." Although the dimensions don't seem to match up well!

[Geoman]

Well, after an unsuccessful search for new bolts, I decided to make my own. Bought a package of M6-1.00 x 25 stainless steel bolts and a 1/4 x 3/8 x 3/4 steel spacer, which I cut to length (approx 8 mm). A little 2-part epoxy to secure the two together should do the trick. We'll see how this works.

[Toran]

Geoman,
Let me know if that works or not. I have a bolt I can send you if you need one.

[Geoman]

Thanks Toran, will do.

[GRS]

Not sure how well stainless steel bolts will work with the ref sensors, since they typically have very low or no ferrittic qualities.

The ref sensors want to see a change in a magnetic field. This is best done with a steel bolt with a high ferritic chemical composition.

The most common 304 & 316 stainless steel bolts have an austenitic chemical composition and are non magnetic and so make poor ref sensor triggers. But other stainless steel types can be magnetic, especially if they go through many types of processes, such as drawing, cold forming, etc. which changes their chemical composition, making them more magnetic than pure stainless steel bolts that are truely austenitic in composition...

Please do let us all know how your flywheel sensor bolt assembly works out for you!

Cheers!

[Rasta Monsta]

lol

[thekidd]

I almost positive that the bolt on the right is the correct stock bolt. On all my cars, except my 924S had the bolt on the right installed along with a figure "8" washer. The washer is the correct measurement ".8mm", the spacing between the flywheel stub and the bottom of the reference sensor.

[Geoman]

Yup that's the original. Well, I replaced the bolts and the car started right up and idled fine. The new bolt went in easy and it "sits" in place exactly like the original. The fact that the sensors are probably corroded and can't be moved, at least easily, probably means they don't even need the bolts to stay in place! I didn't change the sensors because I couldn't budge them, even after two days of PB Blaster, and I didn't want to risk breaking them. That would then require removing the bracket and I was focusing only on replacing the heater control valve. Didn't want to have another job to do. Left well enough alone.