ABS Sensor

[dec322]

I've been having problems with my ABS. It kicks in at about 5 mph no matter what. Yesterday the ABS light came on in the X and they no longer kicked in (which is nice). Some made mention that it might be my ABS sensor. If so, how do I check it and where is it?

 

[TPLYNCH]

Check above the rear differential. That's where mine is.

 

[Dre]

you're a 94 so you have sensors on both front wheels as well...... check all your tires and make sure that they're all the same size..... and that there is no big difference in wear or preasure. Just that can cause your ABS light to come on. Second thing..... did you do anything to your brakes? rotors replaced perhaps? it would be extreme but sometimes people replace ABS rotors with regular ones and have problems..... otherwise - take wheels off and rotors and check sensors for damage...... sensors are installed behind rotors on a hub assembly.... make sure wires are all OK and connected.

hope this helps...

 

[kandtholman]

Correct me if I am wrong but I believe that earlier gen X's only have rear ABS.

 

[Dre]

depends on option package. My 94 Limited had ABS on all four.....

 

[dec322]

Thanks for all the reply's. The problem still exists.

I have ABS on all four wheels. I replace the rotors and calipers and this is when it all started. The rotors should be ok (I hope). I don't remember seeing any wires when I took the old rotors off (do I have a hub assembly since I am just 2wd). I think it is the ABS sensor on the passenger side b/c when the ABS engages it pulls that way. Also, when I bled the brakes again a couple of days ago there was a clicking sound on the front passenger side. It clicked when the brake was depressed.

Based on this site I think it is the ABS sensor on the passenger side. We'll see.

 

[Dre]

nothing's gonna help except to check it all over again. You'll have to take everything apart..... take rotors off and make sure you've got ABS rotors (easy to check since ABS rotors have "ribs" on the inside inner rim of the rotor). Take down pads (duh! - you'll take them off to take rotors off...). ABS sensor will be installed just behind a rotor.... in front of the spindle..... there you should notice wires going to the spindle - follow those wires. Replace both sensors (they come in pairs when you buy new ones). Then put it all back together.... lube pins that hold calipers and voila! you should be fine.

BTW - pulling? I don't think pulling has got anything to do with ABS........ - . - ......... pulling problem - make sure spindle, bearings, ball joints and tie rods are all OK..... and not loose.

there, this shall do......

 

[Dennis94XLT]

Just for the record - You can see the ABS exciter rings by looking behind the wheel - there's a small area where you can see it. Second - after having the same ABS unwanted activity (that's what Ford calls it) I can tell you all what caused mine - and I bet it is causing most of yours too. What you will read next has to do with a 1994 Explorer with 2 wheel drive and 4 wheel ABS. I replaced my rotors twice - getting the OEM rotors each time and no ABS problems ever. The last set of rotors were replaced on mine after I tried those long life ceramic pads. The pads do last just like they say they will, but those pads ruined both sides of both new rotors in about 10k miles. It gouged the hell out of them and wore them down all over. Keep than in mind when you hear the salesman at the parts store try to sell you longer life pads. Just get the cheap ones - you'll replace them more often, but at least your rotors won't get chewed up by pads that have material in them that is harder than the steel in th rotors.
Now on to the rotors. I found I couldn't get the same rotors anymore - all the parts stores (and Ford Parts) had changed from a solid cast metal abs ring with teeth - to a flat metal round part with holes stamped in it. When I put those rotors on my truck, that is when the abs system started engaging erroneously. I replaced all sensors with new Ford sensors hoping that would help - that didn't help at all. I flushed the system - that didn't help. I am now trying to find rotors that have the original exciter ring. Your best bet is the wrecking yard. If you can find two that have at least .875" thickness left, you can probably use them but keep in mind I am referring to th spec for my 1994 model. If you want to see what the Ford original exciter ring looks like, go to www.excellpcservice.com/rotor.jpg and look at the photo - I bet yours don't look like this if you're having problems. If you know where I can get rotors with these same exciter rings pictured - PLEASE LET ME KNOW.
Dennis

 

[Rhett]

Correct me if I am wrong but I believe that earlier gen X's only have rear ABS.

93-94 had 4-wheel ABS. 91-92 had rear ABS.

 

[Rhett]

Thanks for all the reply's. The problem still exists.

I have ABS on all four wheels. I replace the rotors and calipers and this is when it all started. The rotors should be ok (I hope). I don't remember seeing any wires when I took the old rotors off (do I have a hub assembly since I am just 2wd). I think it is the ABS sensor on the passenger side b/c when the ABS engages it pulls that way. Also, when I bled the brakes again a couple of days ago there was a clicking sound on the front passenger side. It clicked when the brake was depressed.

Based on this site I think it is the ABS sensor on the passenger side. We'll see.

I have heard of a bad ABS sensor causing the truck to pull to one side. The problem is the ABS sensor mistakenly engages the piston on that side.

The bolts that hold the ABS sensor and it's casing are often difficult to remove because they tend to rust there badly. The small bolt is a 12 point bolt head, and it's quite small, like 7 mm or similar size. You may have to use quite a bit of penetrant to work the bolts out. I had to drill them out one time.

 

[dec322]

Wow, this is an old thread! I never found out what the problem was. I just pulled the fuse and had a cool light for about a year. Then I replaced my rotors one day and put the fuse back in and it worked fine. I think its what Dennis said about the wheel thing on the back of the rotor.

Now my X has 180000 miles, no ac, check engine light, missing carpet in the back, and a huge dent in the rear from a accident. The money from the accident paid for a rebuilt tranny. She looks rough but she still runs strong!

 

[Dennis94XLT]

Abs

Here's some info that might be of help. If the abs engages and pulls to the left, it is the right side causing the problem. It's the opposite side from the direction of the pull. This info comes from the 1994 Ford Explorer ABS technical manual.
The 1991 and 1992 had rear ABS only and not on all models - some had no abs. The 1993 and 1994 came with 4 wheel ABS - and again some models had no abs, but the ones that had it - had 4 wheel abs.

 

[Rhett]

The 1991 and 1992 had rear ABS only and not on all models - some had no abs. The 1993 and 1994 came with 4 wheel ABS - and again some models had no abs, but the ones that had it - had 4 wheel abs.

Is this info also from the 1994 Ford Explorer ABS technical manual? Thanks for the info, that's good stuff. Now, I have a question for you, where did you get this manual? I want one. Does it say you can bleed the 94 ABS system and not get air into the hydraulic control unit? Or does it say you MUST use the special Ford adapter tool?

 

[Dennis94XLT]

Technical Manual

I got these from a website that sells them for Ford. I don't recall what it's called - maybe someone else does? It's the publisher that runs the website. You can also go the the Ford parts counter and order them. There are 4 manuals for the 94 explorer and you need the one called "Body/Chassis Manual" and the one called the "EVTM (electrical vacuum tech manual)."

You can bleed your abs system without getting air in the abs pump - just don't let the reservoir run out of fluid while you are bleeding them and make sure you don't let air suck up into the lines (keep a tube connected to the tip of the bleed valve and have the other end of that tube submerged in brake fluid.