ABS Sensor

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Niek
Posts: 135
Joined: 18 Sep 2002, 18:09
Location: Netherlands
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ABS Sensor

Post by Niek »

Hi guys,
My front left hand ABS sensor is dead. I tried removing the bolt that holds it in place but it sheared off (probably going to drill it out). But before I go through all that trouble, who knows where the connector connecting the sensor to the system is? All I see is the sensor with a rubberish boot over it, the bolt seems to hold the sensor in place by through the boot.
For all of you smartasses [:D], I measured the resistance at the big connector directly on the ecu (behind the left headlight), three were around 1.07 ohms, the fourth infinite.
She's a '95 Xm 2.0i 16v.
Cheers,
Niek.
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AndersDK
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Post by AndersDK »

Niek -
1.07ohms - did you use laboratory measuring equipment [:D][:D]
The sensors should be some 1Kohms ??? - how did you connect to measure the sensors ???
As for the sheared bolt :
Any chance a few millimeters protrude ?
This last weekend I finished off a headgasket job on a n/a 19RD.
One of the top bolts sheared during removal - much to my panic [xx(]
With the head levered off (a real trial [:(]) - the sheared bolt protruded some 20mm from the block. Was impossible to move with a Stilson.
Prepared to wireweld on a large nut -
But by DaveBurn's advice first tried the good old prooven trick :
Rustloosener (over night) - and then my pressure air chisel anglewise on the stud - to hammer vibrate it.
The rust gunk simply vibrated out the threads around the stud.
Could'nt get my stilson to grip - untill I realised it was the stud that turned [:D][:D]
- it simply winded up by gentle hand force [8D]
Niek
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Location: Netherlands
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Post by Niek »

Alright alright it probably should have been K-ohms [:I] I think the value should be around 1 Kohms because it seems very unlikely [^] that fout sensors broke down at the same time...
I disconnected the large connector of the ABS ecu and with help of a dutch manual measured the spade connectors corresponding to the different sensors.
Thing is though if I can't unplug the sensor and measure the wire I won't know if it's the wire at fault or the sensor.
The bolt protrudes a little at the back, I have very little room there though. But if the sensor comes out with the rubber boot on it the bolt should be protruding by about 5 mms...
I'll try WD40 or something on it, but still have to get the sensor out first thoug???
Niek
ps: the one Bx headgasket I did (last december went absolutely smooth, never knew it could be so easy.. (hope I'll never need to do it again though
Kered
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Post by Kered »

The sensor consists of a coil of wire wound round a square core. This core protudes from the sensor housing and nearly touches the ABS toothed ring. I'm not sure if the core is magnetic or not - probably is so that the ABS toothed ring generates a pulse for every tooth. But what I am sure about is that there are no electronic parts at all in the sensor. (Took 1 to bits out of interest after it failed).
The chances are that it is the cable that has broken, after all, it has to flex one heck of a lot in use!
Kered
jeremy
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Post by jeremy »

I had 3 sensors fail on my BX and re-wired the 2 back ones in situ as I couldn't get them out.
I used co-ax cable with a MULTICORE centre condustor (not TV ariel cable), and carefully soldered both the condustor and the screen, insulating in between. My problem was that the screen had corroded and I cut back until the circuit was complete. One is still working 3 years later, one rear sensor itself failed 4 months ago and a front one had to be re-wired again as I allowed the new wire to kink.
Follow the wires and you should find some joint plugs. The BX ones areunder the rear seat and near to the bulkhead.
Jeremy
mbunting
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Post by mbunting »

I have a similar problem with my F.R. I had a R.L problem before the last MOT, the cable was chafing on the tyre, so I cut it, soldered it, and used insulating tape - it was a very high-tech solution, but it's still working one year on !
I may take a look at the F.R this weekend, but only after I've sorted my R.R. caliper out ( see other thread ! ).
Niek
Posts: 135
Joined: 18 Sep 2002, 18:09
Location: Netherlands
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Post by Niek »

Ok can anyone confirm that for the Bendix type ABS the plug for the sensor isn't actually on the sensor itself though?
Cheers,
Niek
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