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Old 12-08-2017, 08:39 AM
  #16  
J.W. Kiser
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Originally Posted by soontobered84 View Post
Roger,
Can we get somebody to post some up close pictures of the correct ABS sensors? I've got no dog in this hunt, but I don't mind helping look.
Roger, I can when I get back home as we are out of town for a few days. On the ones for the new year models (86.5 and up) do you know why they wouldnĺt work? Was it the girth, the length, the harness, etc?
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Old 12-08-2017, 12:16 PM
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I am in this boat. Will be willing to measure/test/hit with hammer on my car as needed.
Very frustrated with ABS at this point.
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Old 12-08-2017, 01:35 PM
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Not sure if this one for a Volvo would work, but the sensor end looks pretty similar, looks to have plenty of cable length, but would require the connector to be replaced.

W0133-1605588 W0133-1605588
the center extension may or may not be the same dimensionally and would probably be the critical aspect.
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Old 12-08-2017, 01:41 PM
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Wiring and connectors are trivial IMHO. Length, diameter and mounting are more critical. Then comes impedance and if it actually generates the correct pulse as the toothed wheels passes by.
I am hoping that whether it uses a simple coil or uses a Hall Effect sensor, all the Bosch stuff generates a similar pulse.
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Old 12-08-2017, 01:44 PM
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If we can trust the 924/244 guys ( Snarky dig ):
https://rennlist.com/forums/924-931-...cal-specs.html

"I'm not sure that the ABS sensors require any excitation to operate; I believe they're just passive hall effect sensors like the engine speed and reference sensors."

"Right you are. George Beuselinck confirmed this fact for me over on Pelican:
Quote:
Originally Posted by 944 Ecology
The S2 wheel speed sensor will generate a sine wave without other inputs. From peak to trough, it's probably 1.5 volts.

You should probably hook one up to an oscilloscope and see if it meets your needs.
Thanks!"

"If the dash unit needs a square wave of 5 or 12V, the stock sensors wont work without extra circuitry.

If you want some links to hall sensors (that will make the signal you need) let me know."
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Old 12-08-2017, 01:50 PM
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Thanks Simon - I have ordered a couple front and rear from a 940 Volvo.
Compiling dimensions this weekend.
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Old 12-17-2017, 03:59 PM
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Had time to look at this further.
Dealing with the rear sensors first.
I have found an alternative that seems in good supply. However a few questions.
Diameter is the same - bolt location is the same - the top plastc round section with the O ring is smaller but fits. A larger O ring should solve this issue.
Two wire - black and brown so that should make connection easy.


So the problem is length. The small section of metal at the bottom is about 10 mm too long. This is the magnetic part.
Seems solid material. Can this be cut down in length by 10 mm and still work?




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Old 12-17-2017, 06:06 PM
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Definitely worth a try. But i think the point on the end will be important for them to work.
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Old 12-17-2017, 06:35 PM
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It' only a guess, but I speculate the magnet is actually up inside the sensor and the extension if just ferituc steel. I would guess it can be freely machined to the desired shape. The point will give increased resolution as the tooth appoach and departure will give a steeper rise and fall signal since it is acting on a narrower sensor profile.
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Old 12-18-2017, 05:52 AM
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It's worth a try to shorten it by machining. Although it might disturb the magnetic field of the ferrous material
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Old 01-11-2018, 11:16 PM
  #26  
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Hi Roger, I also have the same problem on my 1985 S2, Just wondering if you had any luck with the Volvo option. As an aside the picture does look a lot like the front ABS Sensor.
I did follow the process outlined for repair and managed the repair. Unfortunately now 6 months on the abs light has come on again so without checking yet have assumed the repair didnt last.
Thank you for your efforts here and that Volvo one certainly looks a close fit. Regards Wayne
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Old 02-11-2018, 02:32 PM
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Originally Posted by ROG100 View Post
Had time to look at this further.
Dealing with the rear sensors first.
I have found an alternative that seems in good supply. However a few questions.
Diameter is the same - bolt location is the same - the top plastc round section with the O ring is smaller but fits. A larger O ring should solve this issue.
Two wire - black and brown so that should make connection easy.


So the problem is length. The small section of metal at the bottom is about 10 mm too long. This is the magnetic part.
Seems solid material. Can this be cut down in length by 10 mm and still work?




Any news on this? I may be in the market for ABS sensors for my '85 Euro.

Thanks,
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Old 02-12-2018, 02:07 PM
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I don't have an answer on effect of trimming down the piece Roger found, but would be willing to test it. Interesting that his looks more like the front sensor, which does have a long probe. My measurements show the rear as being slightly wider than the fronts, at ~18.23mm vs ~17.98mm, so Roger's find may be a good fit for the front with a thin shim/sleeve, or just a thick O-ring

Here are some measurements I took to help in the search for a replacement:

Fronts:

Front Body Length


Front Body Diameter


Front Base Diameter


Front Bosch Part Number
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Old 02-12-2018, 02:10 PM
  #29  
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Here are my measurements for the rears:



Rear Base Diameter


Rear Diameter


Rear Length


Rear Bosch Part Number
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Old 02-12-2018, 02:16 PM
  #30  
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Additionally, the 911 Speed sensor 996.606.406.00 also may have some potential as a rear, if somebody had one to take measurements:


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