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My ABS Install Project Page

3K views 20 replies 6 participants last post by  azure 
#1 · (Edited)
I have decided to attempt to install ABS in my 99 wagon that did not come with it. DISCLAIMER: I have already been advised that this a very involved job and probably not worth doing, and I know that others who have suggested the idea have been somewhat discouraged from doing it, but I have decided to attempt it anyway. Of course it is very possible that I will change my mind in the process, but that is neither here nor there. I definitely understand why people generally discourage from this job, as it doesn't really make so much sense to do it and I realize that, but I still want to try it anyway.. So please no further discouragement, although if there is something I am not aware of or that is more complicated than I am making it seem, definitely please let me know.

I am attempting this for three reasons: 1) Because I prefer having ABS on my car (if I didn't it would be kind of a silly project). 2) Because on my "parts car" that has the ABS system but got totalled I had literally just reinstalled the electronic module from the ABS after having sent it out and paid like $70 to get it fixed and it feels like a waste. But 3) which is the most important reason is that I like a challenge, and this feels like an appropriate level challenge, somewhat daunting but hopefully not beyond what I can handle. I know some people will say they think ABS is stupid/unnecessary, or that I should just buy a car with ABS etc etc, but let's just move beyond that please and focus on the topic at hand. Meaning whether you think the project is worthwhile or not, let's just stick to how to accomplish it.

I am hoping to use this thread as a sort of sounding board as the project develops. I will throw in the thoughts that I have and where I am holding in it, and hopefully can get some feedback from those who are interested and who are more knowledgeable than myself (which is probably many to most of you). I don't think it will be completed too quickly, but this site is great for fleshing out ideas over time. No pressure to get involved for any who don't find the topic interesting.

Anyway, my starting point is I know that I have a parts car with working ABS. I plan to pull the module of course from the vehicle. I will simply cut the brake lines at the fittings and carefully remove them to hopefully reuse them. I will use Cu-Ni line and I have a cheap bubble flare tool that I have used successfully in the past. I will have to run entire new lines for the car, should be a total of 8 runs, two going in to the ABS, four coming out, and then the rear lines go through a control valve before the wheels. There is no rear prop. valve on a wagon. I will replace all lines, as the rear ones on the donor car were for drums anyway, and I may relocate the ABS unit. Plus I WANT new lines... I should add at this point that part of my reasoning for doing this project is that I kind of wanted to run new brake lines anyway as they are old and rusted, so it's kind of useful work anyway in that sense at least.

My current car already has axles in front with tone rings. I don't have rear hubs with tone rings, but those are cheap to buy, either new aftermarket or used OEM (don't think they go bad too often?). I have pulled the front two sensors already. I can pull the back two also, although there is a little bit of confusion, as Rock Auto lists the sedan and wagon as having different rear ABS sensors; I'm not exactly sure why. The donor car is a sedan, so hopefully I can still use those sensors, if not I'll have to buy new ones for the back.

So that covers brake lines, sensors and tone rings. I think the only other major "component" of this job is the wiring. I might add at this point that it occurred to me that since I am doing this job from scratch I can really install the ABS unit wherever I want, i.e. wherever I can find a convenient work space that doesn't block other important stuff. My wife even joked I could install it in the car interior which is technically true if I could find an opening to run brake line in there. I just think that running the lines and wires would be much easier in an "easy to work" location, perhaps underneath the back of the vehicle somewhere? I would just have to find a way to mount it, not a big deal. Does anyone know a reason that the brake lines going in to the ABS should be short, and close to the MC? I wouldn't think it matters; on my Suburban the ABS unit is under the car like halfway back or so. The only obvious and glaring inconvenience of moving the location significantly would be the wiring. (Edit: Now that I think about this further, I don't think it would make sense to move it very far from the engine compartment for another reason: the rear lines need to go through a "control valve" after the ABS but before they go to the rear wheels. So would be kind of crazy to run them from the MC to a distant ABS then back up front again and then back again. I need to go peek inside the hood though, because maybe this control valve itself could be easily relocated as well?)

So speaking of wiring, it's not my area of expertise, but I know a bit about it. I should mention that I've never done anything like this before. But I think I understand more or less how it needs to be done. It doesn't actually seem like there are a ton of exotic locations that need to be accessed. Below is a pin-out schematic:

http://www.taurusclub.com/forum/att...fter-hub-replacement-abs_connnector_c1057.gif

There are 16 pins that are used. But if you break it down, 8 of them are for the wheel sensors, which are easy. Two are ground, two are always hot, one is hot in start or run. Also, I don't know exactly where the best place to get those is, but I can certainly get them from any number of locations. The three hot wires should have an appopriate size fuse inline. That only leaves three more wires: The brake on/off switch, an ISO link (not sure exactly where that goes), and the ABS light indicator. My thought on the indicator (tell me if you guys think this is crazy) is that since I can't be 100% sure if that light even exists in my dash, and I also don't want to have to start tearing apart the whole dash, I was just going to take a cheap LED from ebay and run the wire from that pin to (and ground from) that LED, which will serve as my "ABS indicator light." I can place it anywhere I want. And the cool thing about this job is presumably initially when I wire in battery, ground, and the LED light, the LED light will go on, because the system isn't functional. And presumably as soon as the system is fully wired up correctly, the light will go off, indicating it's wired properly. I wonder if an ABS light would be tripped because of no brake lines or fluid in the unit, or if the module could successfully self-test "dry." (I looked at a list of all DTCs for the ABS system and none of them had anything to do with brake lines or pressure; they were all internal to the system components, sensors, etc.)

I will pull the connector itself from the donor car, and do my best to trace the wires to where they go, and pull the wires also if I can. At the end of the day it seems like the only truly mysterious location to me is the ISO link.

In another thread some people suggested it would be necessary to pull the PCM and who knows what else from the donor car. As mentioned I know little about this topic, but I'm seriously doubtful if that is the case. It does not seem that the ABS needs the PCM or vice-versa, although there is clearly back and forth communication about the DTCs or the ABS system's "readiness." What I'm wondering is, does the PCM really "care" if ABS is suddenly installed in a car that didn't previously have it? It seems to be a totally autonomous system. People do take ABS units from junkyards and install them in their car, although granted those cars had ABS previously. I own a pirated VCM Ford scan tool, which is supposedly capable of "flashing" PCMs with new modules or whatever (not that I really know exactly what that means) so is it reasonable to assume that either nothing will need to be done, or that this "flashing" would be sufficient?

So if I have correctly covered the basics (which I'm not sure if I have; please fill me in if I'm totally wrong on something) this job basically entails: Having four tone rings, four wheel sensors, running appropriate brake lines, finding an appropriate mounting location for ABS, and locating the correct wires or locations to run new wires in order to get the connector together. And possibly "talking" with the PCM.

Any thoughts?? I know some of you will think I'm nuts, but I like the idea of this kind of project, so humor me....plus besides for the knowledge and insights that people on this forum have, it's nice to have some moral support as my wife and friends probably think I'm crazy and don't understand the appeal of taking on a challenging project that doesn't seem to promise spectacular results (other than hopefully a working ABS system and new brake lines at least).
 
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#2 ·
If I am correct that I can do the wiring and have the system self-check itself before installing any brake lines, then I have the liberty of doing the wiring at my leisure, and then installing the unit and lines only when I know that the wiring is already properly taken care of. I imagine I'll need some kind of adapters to connect the spade or whatever it is that's in the connector directly to the pins on the ABS when I want to check wiring without actually putting all the wire into the connector....?
 
#3 ·
Maybe you haven't thought of this but by adding ABS you will create a vehicle that will make you a target in any accident you are in and may cause insurance to not pay claims. You are modifying a significant safety system. Selling the car maybe an issue also due to liability issues.

Other than that was the donor car a wagon because the weight distribution is different and may mean a different module. Don't know just suggesting something to research
 
#4 ·
Thanks for the thoughts, happy for people to point out possible flaws or challenges! That is an interesting point about liability. Although technically speaking that line of reasoning could apply to many mods that are much simpler, for example the 11.6 brake upgrade and wheel size change that many people do, etc etc. And also it wouldn't be known that I modified the car. In fact, if it could be verified that it was properly installed, it could only be considered to make the car safer. But definitely food for thought. I don't plan to ever sell the car, and my research indicates that the wagon and sedan use the same module. Thanks!
 
#5 ·
It is easy to verify if the car originally came with ABS or not via the VIN.
 
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#9 ·
Update: I haven't written all the little updates as I don't want to bore anyone with the details but I have made a lot of progress on this project; I'm very excited. First of all, it turns out that my rear hubs already are the ones with the tone rings. Not sure why; maybe they were replaced (unlikely, car only has 60k miles) or maybe Ford put them in OEM for some reason.

I also removed the actual ABS unit from the car. I will reuse the two lines going from the MC to the ABS unit, as well as the front left brake line. All others I will redo. They are pretty rusty on both cars. I bought plugs for all the brake line ports on the ABS so that I can work with the unit without fear of dirt and contamination inside it. Well actually I couldn't find M10 and M12 plugs, so I bought M10 and M12 adapters that are meant for regular 3/16'' line, and put 3/16'' line plugs into the adapters.

In terms of wiring, I carefully studied the various wiring diagrams as well as tracking down where all the wires go on the donor car and figured out how to route everything. I then de-pinned, or cut all wires as appropriate, and removed the wiring harness.

Turns out the ISO link wire that I mentioned is just a wire that goes to the OBD port. That wire, as well as the wire that goes to the ABS light both go below the dash via the huge wire harness that lives inside the LF wheel well, and they go into one of the "small boxes" next to the under-dash fuse box that has a bolt going through it. The wires coming from the engine compartment have male pins, and the ones coming from the dash that go into the "small box" connector have female pins. I really wanted to know if my non-ABS car has those female pins coming from the dash into the small box. If not, it would be a lot more work to attach those wires. I was very pleased to find out that the female pins (i.e. the wires) were there!!

So last night I very carefully routed those two wires in to the OEM place that they are supposed to next to the under-dash fuse box. Very proud of myself. Right now I have the wheel sensor wires and the BOO switch wire all removed (depinned) from the connector, as my goal is to just work with the three power wires, the two ground wires, the OBD link wire, and the ABS light wire. Those should be sufficient to see if the car recognized the ABS. Then, finally when I have all wires working properly and no DTCs stored, I will install the ABS unit and route new brake lines. Hopefully this way my car will only experience a day or two of "down time."

I twisted the power wires together from the connector and crimped a temporary ring terminal to them, and did similar for the ground wires, and connected each ring to its respective battery terminal. And the OBD wire and ABS light wire were already properly attached as mentioned. Then I attached the connector to the ABS unit to begin testing. My plan is to store the connector this way right now next to the battery, and just leave the ABS in my trunk so I can test or work on it as needed. Anyway, upon connecting it I heard the relays inside the ABS module clicking. Good sign. I very excitedly put the key in the ignition hoping to see the yellow ABS light and.....nothing. Attached my scan tool to see if it recognized the ABS and.....nothing.

Ok its a setback. Those who said the PCM needed to know the ABS unit was there, or that the ABS itself needs to be flashed, were correct. I knew that this was a possibility but was still a bit disappointed. So I took out my cloned Ford scan tool (VCM II) to flash the PCM or ABS and lo and behold, the software informed me that that option was not available. D'oh!

So after reaching out to an ebay seller of cracked IDS sofware from Russia, and sending him pictures of the chips inside my cloned VCM, he confirmed for me that the hardware of my unit looked fine and that the Chinese IDS software often does not include the modules necessary for flashing/programming modules. For $35 he sold me his version that does, so hopefully in the next day or two I will have an update on this matter......
 
#10 · (Edited)
If it works out, and the car recognizes the ABS, all I will still need to do is install the wheel sensors and wire them up which isn't a big deal, install the ABS bracket and unit, and run the lines, like I said. Although this project took a lot of initial research, mostly for the wiring, so far its seeming like the implementation phase isn't too crazy. Again, that's assuming and hoping that flashing the modules does the trick........ Even if someone out there wants to do this install and doesn't have a VCM, I've heard that Ford should not charge more than half an hour of labor to flash the PCM supposedly.

The only real question that I still have in this process and still do not have the answer to is about the proportioning valve. I have posted a thread about it, but did not get any replies. I really hope someone out there can help me on this one, please...

I will reiterate the question here:

Since I have no access to a front proportioning valve from a wagon with ABS (wagons have their prop valve right after the master cylinder, NOT in the rear) and they aren't sold on ebay, and I don't live near any junkyards, I plan on trying to use the non-ABS one. The only difference between them (at least I THINK) is that on the non-ABS one the two MC lines go into the prop valve, and four lines come out (It's really two seperate prop valve units; one for the LR/RF circuit and one for RR/LF). The two front lines get full pressure, and the two rear ones are valved to get reduced pressure at a certain point. On the prop valve for an ABS wagon, however, only the two rear lines enter the prop valve, and exit it, as the two front lines come out of the ABS and go straight to the wheels (at least that's what I think; I've never seen that prop valve.)

So I'm thinking I can simply plug the two outlet ports for the front lines on the non-ABS prop valve, and that should still give the rear lines the correct proportion of valving (instead of two going in and four coming out, two will go in and two will come out.) I'm almost positive this should work without a problem, the only thing I'm thinking is I don't understand exactly how the splitting is done internally inside the prop valve; is it possible that by plugging the outlet for the front line I might cause the rear line to get more pressure than it is supposed to get? I'm assuming that that would NOT happen, because however the rear line is mechanically valved, it should be independent of what is going to the front line. But since the front and rear line share a common inlet and must split the pressure, I just want to make sure I'm not doing anything stupid.....
 
#11 ·
I looked into retrofitting ABS on my 98 sedan with rear drum brakes. The first thing I found out was the tone rings were different between drum and rear disc brakes. Those on drum brakes are stamped from sheet metal and have fewer teeth, disc rings are machined and even available in help section at some parts stores.
Long story short, I upgraded to rear discs and didn't feel ABS was justified.
4 wheel disc brakes are a huge improvement over rear drums because they can be modulated much easier by the driver. They don't have the drawback of servo leading shoe that drums do. This action increases braking effectiveness at the wrong time in a panic stop as weight is transferred from rear to front causing lock up.
My former 64 VW hotrod Squareback with mid engine, 71 Dodge van and 98 all have 4 wheel disc brakes, hence my name.
 
#12 ·
I already have four wheel disc brakes on my wagon. I do like having ABS, but the main reason I'm doing this is because I enjoy the challenge. I've learned a lot about automotive wiring while researching this. It will be really cool if I can actually make it happen...
 
#13 ·
I wish I had a no ABS car. My 04 taurus ABS control module when it's failed. ECU detected the ABS issue and turned the red brake light on and I was not able to pass the state vehicle inspection because of the brake light. It took me at least 8 hours to fix it plus lots of hours of research.
 
#15 ·
Well it turns out that you're right, flashing the PCM didn't help to enable the ABS. I was able to successfully use my tool to flash the PCM which was cool, but it didn't help. Then I pulled the PCM from the ABS car and put it in my car and flashed it, but still didn't help. (was cool though to see that my cloned chinese tool and software was able to reprogram a PCM in a PATS car.)

But I realized I'm probably overthinking all of this. I'm going back now to my original hypothesis, which is that the PCM does NOT need to communicate with the ABS module in any way. I've studied all the relevant wire diagrams carefully, and there's no reason to assume that it does need to. It's just that with what I presumed was a "known good" ABS unit, but the car wasn't recognizing it, I was assuming that there was just something I didn't understand about the PCM and wiring since I'm pretty new to this stuff. But I'm going back to basics. Maybe the ABS unit that I was assuming was good has some issues with its internal soldering, which is VERY common in these units and can result in inability to communicate with them. I hadn't considered that, because the unit had been repaired in the past and was known to have worked. But the car was in a crash, and perhaps something was damaged in it. I can get a used unit on ebay that supposedly works for like 30 bucks so I'm considering that now.
 
#17 ·
Not really because in my posts above I describe exactly what the ABS vs non ABS car wiring is. There are very few differences other than the wheel sensors and the BOO switch. The only other wires are to the ABS light and to the OBD connector. And I have confirmed that those wires (as well as power and ground wires for the ABS) are wired correctly. And have confirmed physical presence of the ABS light (and it lit when I gave its pin 12V). So the only possibility I can think of at this point is internal soldering.
 
#20 ·
It turns out that my initial hunch was right all along. The PCM or the car or anything else does not seem to need ANY knowledge whatsoever as to whether or not there is an ABS module in the car. It is all internal to the ABS and its own internal computer. And the only link to the car from the ABS is to the OBD port (and the ABS light). And the reason that my car was not recognizing the ABS was as I predicted: Internal soldering issues.

And it's actually pretty straightforward to fix it yourself. It seems that the most common issue making these ABS units "go bad" is as follows: The (male) pins that are on the ABS module end of the connector are attached on the inside to little metal tabs. Each pin has a tab. And there are thin wires that are soldered from the internal chip boards to those tabs. Apparently, sometimes those wires become separated on the pin/tab end. If they were to become separated on the internal chip board end, it would be quite difficult and probably take somewhat of a professional to address the issue, as those boards are not easily accessible. But fortunately it seems that the most common issue is to separate on the pin/tab end, which anyone with soldering experience should be able to rectify. All you have to do is open up the unit and you will see what I mean. Full disclosure: I have literally ZERO soldering experience before this, and I will admit that it was very difficult for me and took a long time. But eventually I did it after a lot of tries and retries. And then I hooked up the ABS to my car and it worked! ABS light lit up, and the OBD link gave me DTC codes!! I was super excited after all this work. It's kind of ironic that it didn't occur to me earlier that the unit could be "bad," but it was previously a "known good working unit," which is the worst type of problem to ever diagnose because you never question or doubt your initial assumptions about the part that was "known to work." But seemingly it had developed further "solder separation" in the interim.

I actually did something kind of stupid, and because I have so little soldering experience, my "blobs" of solder on the tab and wire were huge, but I still made sure they weren't touching each other (and confirmed by checking continuity between "blobs" with my multimeter). But the stupid thing that I didn't realize until I had soldered all the tabs is that some of my "blobs" looked like they went low enough to touch the metal case of the ABS module itself! Meaning they were all shorted to each other! Those tabs happened to all be for wheel sensors, which I don't even have those pins/wires in my ABS connector right now, as I am only working now with power, ground, ABS light and OBD link wires, as I've written earlier. So it was irrelevant for now, but I will have to fix those few tabs later that were touching the case.
 
#21 · (Edited)
So I have pretty much realized that this job is overall VERY manageable. If you start off with a working ABS unit (or fix it first) the wiring for the job is NOT extensive. It took me a long time to initially figure it all out, but the actual execution wasn't too bad when the kinks were ironed out. Now all I have to do is the wheel sensors (and run their wires) and then flare a few brake lines and I'm done!

Of course I'm making it sound too easy, and I'm sure other kinks could develop. But the project seems manageable. Eventually when I'm done I'll probably try to write up a brief guide to doing it if others are interested.
 
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