Scorpio ABS sensor substitution

[brokencase]

Does anybody have a spare front ABS sensor for a Scorpio on the shelf that they can measure for me?

I need the diameter and height of the "cylindrical portion" that goes into the hub.

I think I may have found an inexpensive substitute.

[Ed Lijewski]

D= 17.8mm
H= 24.4mm (including O-ring groove).

YMMV

[brokencase]

Bingo! I think we have a winner...

The height of the cylinder is a little longer at 27mm. But a 3mm spacer can easily be made to take care of this.

Ed, check the center to center distance. (Center of center of cylinder to center of mounting hole)

Next step is to install on car with some sort of rigged connection to see how it performs.
The problem is I don't have anywhere slippery to test!

If all goes well, I can cut/splice the connector side. It would really be nice if I could find the mating connector to
the one on this sensor.

The unit cost under $10. But i won't say where it came from until I test it out first.

[Ed Lijewski]

I measured the sensor dimensions on the spare set in my stash; can't get the other measurements for now.

YMMV

[brokencase]

No problem. I'm going to try a test fit on the car tommorrow. I am optimistic the mounting bolt hole will be "close enough".

I found the following regarding testing. This is from "Debuging the Milano ABS" (Teves)

"Check the speed wheel clearance using a brass feeler since the pickup is magnetic and set it to factory specs.
The fronts should be 0.7 mm and the rears 1.1 mm. You can check the AC behaviour of the sensor
by lifting a wheel and spinning it. You can use an oscilloscope or a multi-meter and you should see
a small AC voltage being generated. At 1 rev/second you should see an AC voltage of between
0.15-0.7V."

So I will set clearance and spin the wheel and check with the o-scope. This subsitute sensor has a 1500 ohm resistance and the manual says 800-1400 ohms for original sensors. But I don't believe that to be a problem. If you are familiar with magnetic pickups on guitars the higher resistance only means more windings. If anything it means these will put out a stronger signal.

The only question is what to do about the connector? I could chop the connector off of the old wheel sensor and splice it on to this sensor....or I could 3d print the mate to the connector on this sensor and adapt on the vehicle harness side...

The downsides.. No groove for o-ring. A smear of silicone will address that. These are also all plastic construction.

[brokencase]

Did the test fit today.. If it were not for the connector I would say that this sensor is practically a "drop in".

The cylinder lengths are very close. I can mount the new sensor in the hole and spin the hub and I don't detect any interference.
However, I measure the length from the base of the cylinder to the tip of the pole to be about 27.8mm on the original Scorpio sensor.
The "new alternate' sensor measures about 0.4 mm longer at 28.2mm I think it works out nice to put a thin gasket around the base since there
is no O-ring seal on the new sensor.

As you can see in the pics below - the original mounting bolt is too short and a longer replacement will be needed. I will look for some
stainless metric cap head bolts. The mounting hole lines up just fine!

I hooked up my mini oscilloscope and spun the hub to see the expected AC waveform. However - notice the difference in the poles on the tip of the sensors. Hopefully this won't have too much impact.

The rubber strain reliefs that slide over the cable and "snap in" to the sheet metal brackets are identical. However they are in the wrong position on the cable. I was able to apply dish washing detergent and slide them to the proper locations. There is a "plug" to go through the body work hole that might fit the hole on the Scorpio. Otherwise the cable is longer than the Scorpio sensor's and this leaves plenty of room for splicing. I think I will cut the old connectors from my sensors and splice them onto the new sensors.

[brokencase]

The alternative sensor under investigation is from a 2000-2006 Ford Transit.

I bought three from Banggood.com and I think they are now out of them
https://www.banggood.com/ABS-Wheel-Spee ... rehouse=CN

You can also get them from here...
https://www.aliexpress.com/item/Wheel-S ... 56732.html

...or here...
https://www.lifeitnow.com/product/abs-w ... gJXU_D_BwE

You can probably find them elsewhere. But probably not from a USA vendor because they did not import the Transit to US until 2010 or so.

Be advised I have not yet proven these out and the normal "at your own risk" exclusions apply...

[Bob Weir]

FYI It's my understanding, the wires [ABS to wheel] are wheel specific, but that may only be due to different lengths.

[brokencase]

What do you mean Bob? Connectors to these sensors are different. They need to be adapted. I bought some weather sealed two teminal connectors from ebay that I think i will use. Like these

https://tinyurl.com/y2fm5f2c

These units appear to be much longer than the Scorpio's and can be cut to length.

Still haven't gotten around to trying them out yet.

[Bob Weir]

If I remember correctly, when I removed them from a donor, all 4 cables were of different length. From shortest to longest: Left/front, right/front, left/rear, right/rear. Jeff Herson & Jan Talian should know for certain.

[Ed Lijewski]

Bump for progress report.

YMMV

[brokencase]

I'll be honest Ed, They are still sitting in the box.

I'm still waiting for "full failure" of my front ABS sensors. At the time that I bought these every once in a Blue Moon I would get an ABS light when I hit a bumpy section in the road. With my previous Scorpio, I had a failure of the front ABS sensor so I suspected that the same would be imminent with my current Scorpio. But full failure has not happened yet. In fact I have not seen the ABS light come on in a long time, but I know that my ABS is still functional, as I have felt it being applied in wet conditions.

But since these were so inexpensive, I bought three for spares for the long haul.

I also bought a rubber sealed automotive connector assortment off of ebay. My intent was to chop off both mismatched existing connectors and install the new weather sealed connectors.

I am confident these Transit sensors will work, but naturally, it would not be proven fully until I actually install them.
Internally these are pretty simple inductive sensors. I would be very surprised if they did not work. As you can read from above I was able to connect an oscilloscope and verify a proper A/C signal was being generated.

They cost so little, if you need one...take the plunge.

But if you are a scared wimp and unwilling to take any risk (which I suspect you are) you can always buy this...
https://www.ebay.com/itm/123039498161

These are like the connectors I bought...
https://www.ebay.com/itm/233100043449

Search ebay further you might find the connectors at a better price.

My earlier links to the transit sensors expired...here is a current one on aliexpress.
https://www.aliexpress.com/item/4000540082634.html

[Ed Lijewski]

The ABS can easily be tested by stepping firmly on the brakes on a gravel/stone road surface.

Next step is to install on car with some sort of rigged connection to see how it performs.
The problem is I don't have anywhiere slippery to test!

Why do you think the different "poles" won't be an issue (why are the poles different)?

Re the connectors, I assume the Scorpio cable woven shield (you can only see this if the outside insulation is broken) is not there just for signal protection but is also connected to the copper fingers part of the connector:

20210830_170221.jpg (1.72 MiB) Viewed 3228 times

How can the Ebay connectors be fitted on the Scorpio cable?

Screenshot_20210830-170617_Firefox.jpg (353.81 KiB) Viewed 3228 times

YMMV

[brokencase]

A coaxial connection is not mandatory. Polarity does not matter either since it is just an induced AC signal. I'm not even sure the new sensors are coaxial cable, The connectors of the new sensors are not coaxial either.

Weather sealed connectors are important. The new connectors above are probably better than the original Scorpio connectors.

As I described previously, I inserted the sensor in the hub and spun the rotor and observed a correct signal on my oscilloscope.
So I have no concerns.

[brokencase]

BTW, it is a shame you did not buy one of those sensors back when I bought mine.
I think I got 3 of them for a little over $30 dollars shipped.

Now they are more expensive and the shipping costs from Asia have gone up.