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  #1  
Old June 13th, 2009, 01:12
fyrfytr1717 fyrfytr1717 is offline
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Thumbs up THE XJ Dana 44, ABS, How-to thread (56K beware)

OK, so here it is. The XJ Dana 44 ABS thread I've been promising for so long. All you ABS haters can just click on by and continue to hate anyone interested in maintaining their factory ABS when they upgrade their rear end. I’m not going to get into the pros and cons of ABS in different driving situations. I’ll leave that decision up to you. I’m also not going to show you how to swap in a new rear end, there’s many, many threads already in existence about that. I won’t cover disc brake swaps or how to make ABS with work them. I’m just going to show you how easy it is to maintain your ABS when upgrading your rear end to a stock XJ Dana 44. So if you’re interested, grab a cold one and be prepared to do a little reading. This is going to be long, but I promise, there will be LOTS of pictures along the way.

The usual disclaimers first… Modifying your braking system may be dangerous, do it at your own risk. Additionally in this write up I’m using an ’87 XJ D44 and swapping it into a ’99 Cherokee Classic that originally had a D35 with ABS. I’d imagine all ’87 XJ D44’s are pretty similar, but I’m not familiar enough with the older ABS systems to tell you if this will work on a pre ’97 XJ or not. Maybe somebody that has an older ABS system can chime in later and let me know.

So here we go….

Parts you’ll need:

From your Dana 35-
Brake lines
Brake line guides
E-Brake cables
ABS sensors
ABS sensor mounts
ABS tone rings

From your Dana 44-
Axle housing
Axle shafts
Backing plates
Brake hardware
Brake shoes
Brake drums

Additional parts-
None, unless your brakes are in need of a rebuild

Required tools-
Typical mechanic’s hand tools
Feeler gauge set
Compass (circle drawing type)
7/8” hole saw
7/16”-20 tap set
A lathe (or more likely, access to a competent machine shop)
Tools for bearing removal/install (again, I’d have someone do it for me)

Optional tools-
Torque wrench
Dremel
Welder (Either the machine or the person, whichever suits your needs)

First off, here’s the Dana 35 and Dana 44 axle shafts side by side for comparison.





The Dana 35 backing plate and brake assembly.



And the Dana 44 backing plate and brake assembly.



This is the orientation of the sensor and the tone ring on the Dana 35 and is what we are trying to recreate on the Dana 44.



After a lot of careful measuring, I determined that in order to get the tone ring where it would properly match up with the sensor, its outer edge needed to be exactly 1 3/8” away from the surface of the retainer plate. I used the retainer plate as a reference point as it was close by, easy to measure from, and it’s the surface your ABS sensors will mount up to. You can see the marks I scribed on the flange in the following picture indicating where the tone ring has to be mounted.



I realized while writing this up some of you may have already removed your retainer plates. I figured you could use the wheel mounting surface for a reference, but I can’t get an exact measurement with the axles and brakes already installed. As best I can tell it is 1 1/16” from the WMS to the outer edge of the tone ring.

I wanted to remove as little metal as possible when installing the tone rings so I asked the machinist to turn the flange just until there was a nice machined surface for the rings to press onto. Turns out that at exactly 2”, the rough casted surface is machined off, leaving you with a nice clean shoulder to press the rings onto. The inside diameter of the tone rings are then machined out to 1.999” for an interference fit. Unfortunately, I don’t have any pictures of either part as the machinist pressed all the parts on before I could take a picture of them. Here’s a picture of the finished product (after a fresh coat of paint) with the dimensions drawn in to help eliminate any confusion.



And the pretty pair all ready to be installed.



So what’s this going to cost to have done by a competent machinist you ask? Well, that all depends. The going rate where I live is $80 per hour. I brought in my old axles, new axles, and new set of bearings in a milk crate. I told him what I wanted accomplished and asked him to just take care of it all. I ended up getting charged for 2½ hours of labor. He said the machining only took about 1 hour, but taking the rings off the old axles, taking the bearings and retainer rings off the new axles, and then reinstalling all the parts afterwards made up the other 1½ hours. If I were to do it all over again, I would have removed the tone rings from the D35 axles, cut the bearings and retainer rings off the new axles, brought just the D44 axles and tone rings in to him for machining, and then brought all the parts in to an auto shop to have the bearings pressed on. While he was an excellent machinist at $80 per hour, he was a pretty lousy mechanic, especially at that price. He used heat to get the retainer rings on and I think he installed my axle seals dry as I had to replace both of them within a few months due to them leaking. I had new ones pressed on for $20 per axle by another machine shop that dealt more with automotive applications and have had no problems since then.
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  #2  
Old June 13th, 2009, 01:16
fyrfytr1717 fyrfytr1717 is offline
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Re: THE XJ Dana 44, ABS, How-to thread (56K beware)

Next challenge, the backing plates. Really simple actually. They just need holes drilled in them for the ABS sensor wires to run through. The only tricky part is finding enough open space for the holes without interfering with anything else.

Draw a 1¼” circle on a piece of paper and cut it out. Experiment with different locations on the backing plate until you find where it will fit without interfering with the brake shoe glide pads, the e-brake cable hole, or the spring retaining pin holes. It needs to be roughly in line with the axle, on the front half of the backing plate. Use your old D35 backing plates to give you a rough idea of where they should go.



Mark the center of the circle with a center punch.



And then drill a hole with a 7/8” hole saw. So why use a 1 1/4” circle instead of 7/8”? The 1 1/4” provides room for the skirt on the ABS sensor grommet.



And that’s it for the backing plates.

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  #3  
Old June 13th, 2009, 01:23
fyrfytr1717 fyrfytr1717 is offline
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Re: THE XJ Dana 44, ABS, How-to thread (56K beware)

Next up is the ABS sensors and wires. You can’t just pop the sensors through the holes in the backing plates so they need to be unplugged from the ABS module and fed through. You can find the module (and the plugs) under the rear seat, on the driver’s side next to the transmission tunnel. Unplug the small red and black plugs.



Feed the wires out through the holes in the floorboard, and finally through the backing plates.



Be sure to save the sensor mounting brackets when you remove the sensors from the axle. You will need to re-use these.

Next up is the brake lines. This really has nothing to do with the ABS swap, but I thought I’d include it anyways. The brake lines on my D44 were pretty corroded and I like the combination brake block / axle vent the D35 uses better than the crappy plastic nipple the D44 uses for the vent tube.

The following quick step solves two problems at once. It gets rid of the plastic nipple, and if you hadn’t already noticed, the brake block on your D44 is a little further outboard as the vent occupies the position used for the brake block on your D35. This means that if you’re going to use your D35 brake lines, the driver’s side will be too long and the passenger side will be too short unless you relocate the block. On the flip side, if you plan on keeping your D44 brake lines, do not take the following step as your lines will be the wrong lengths.

Drill out the vent hole on the D44 with a 25/64” (3/8” worked just fine too) and use a 7/16”-20 tap to thread it. Make sure you get all the shavings out of the axle tube before putting it back together. The brake block from your D35 should now thread right in. You’ll also want to plug the hole that the old brake block threaded into.



Also, I don’t know for sure if it is necessary, but you may want to shorten the vent/bolt a little before threading it in. The end of it appears to be contoured to the shape of the D35 shafts and I figured since the D44 shafts are thicker, it would probably be a safe bet to shorten it up a bit. The larger diameter of the axle housing on the D44 may compensate for the thicker axle shafts, but I really didn’t want to chance it so I just ground the bolt down a little.

Next, you’ll need to gently reshape your lines as the contours of the D44 are a bit different than the D35. I found the easiest way was to first straighten them out, and then gently bend them to the proper shape, making sure not to kink the lines. At this time you’ll also want to reinstall your ABS sensor wires as well as your e-brake cables. You’ll notice that I have attached the ABS sensor wires to the brake lines and secured the brake lines to the axle housing using all the original clips and hardware from my D35 axle.

Driver side



Differential



Passenger side



The whole shebang all mounted up. If you have a later model XJ with the e-brake lines routed down the driver side of the unibody, you’ll have to re-use your old e-brake cables as the ones used in ’87 were equal lengths and will not reach the passenger side brakes. The ends look a little different but they work perfectly. Incidentally, you can re-use the little metal bracket that secured the passenger side e-brake cable to the top of the differential housing on your D35.


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  #4  
Old June 13th, 2009, 01:36
fyrfytr1717 fyrfytr1717 is offline
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Re: THE XJ Dana 44, ABS, How-to thread (56K beware)

Next up, and ironically what I found the most challenging, was the sensor mounts. Here’s where all the voodoo, mystery, and magic surrounding ABS brakes comes into play. The ABS sensors are essentially magnets. As the tone rings spin past them, each little ridge causes a pulse to be sent through the sensor and up to the ABS module. In order to get a good pulse, the gap between the sensor and the tone ring has to be within FSM tolerances. This is easily adjusted using a feeler gauge. That’s it, pretty simple, huh?

It would be, except that the bolts that hold the backing plates (and thus the ABS sensor mounts) on the D35 are closer together than they are on the D44. This means a little fabrication is in order. I tried like hell to make this a no-welding-required project, but found out in the end that in order to do it right, two small welds, each about ½” long, will have to be made on the mounts. You can do it without welding, but it will make things more difficult for you down the road. I’ll show you each of the attempts I made starting from no welding and working up to what I believe is the best way.

First, a picture to demonstrate the problem. As you can see the bolts are further apart on the D44, no two ways about it.



If you look close in the above pic, you’ll see I ground a notch into the end of the mounting bracket to make it fit right up against the bolt. This was easily done using a Dremel with a small grinding stone.



When installing the mount, I sandwiched it between a washer and the retaining plate. This worked OK, but I found that when you torqued the nut down to FSM specifications, the mount had a tendency to get spit out from behind the washer. You could make it work if you held it in place while tightening the nut, but it really wasn’t ideal.



Next attempt was to cut open the bolt hole and spread it to create tabs to be sandwiched on either side of the bolt.



This worked out much better during installation, but I found out while putting in my second set of bearings that torquing down the nut had caused the tabs to deform, rendering them almost useless for a second installation.

Both of the above methods were at best a one time use modification. Ease of install and durability however were not the only issues. Due to the brackets being off center, the sensors are also off center. This prevents the sensors from being able to line up perpendicular to the tone rings at the proper gap. The sensors adjust in an arc, so once you got them close enough to the tone ring, they lined up at an angle instead of flat. This caused sensor adjustment to be very difficult. With a lot of trial and error, I finally managed to adjust them “close enough”.

If they are adjusted improperly, the ABS module thinks you have a wheel slipping just as you’re coming to a stop. They will work fine at high speeds, but just as the vehicle is about to stop, you’ll feel the ABS pump cycling like mad and the pedal will get really soft. You’ll still stop, it’s just really annoying and you’ll grow tired of people asking you why your brakes are making that farting noise every time you stop.

Here’s a quick drawing of correct and incorrect sensor alignment. I couldn’t edit the image to give an actual representation of the sensor/ring alignment, but it gives you an idea of what I’m talking about. You’ll have to actually mess with them to see exactly what I mean.



We’ll refer back to the above picture in just a bit. So on to the right way. Cut off the ends of the mounting brackets and get yourself a couple of pieces of appropriately sized scrap metal to extend the mounts with.



With the axle shaft in place, loosely install the sensor mount using the remaining bolt hole and then loosely install the sensor on the mount. Using the bolts as pivot points, rotate the mount and the sensor around until you find the orientation that gets the sensor looking as much like the “Correct” picture above as possible. Snug the bolts to hold things in place and then figure out the proper angle and shape of the extensions. Weld them on, and drill your new bolt holes in them. Regardless of the shape of your bracket, the bolt holes should be exactly 2” on center in order for them to slide smoothly onto the bolts. The welding doesn’t have to be perfect. Shoot, it doesn’t even have to be pretty. You could probably even JB weld the pieces together if you trusted the stuff. Just so long as it will hold the two pieces together when you torque down the backing plate nuts.



A little bit of primer/paint and you’re good to go.



I should note however that the mounts in the above picture were not my final version. Initially, I mocked one up as described above and then made the other one an exact mirror image of it. That is why they look the same. My problem became obvious when I went to mount the second sensor. They in fact should not be the same. Since the left and right sensors are identical other than the length of wire attached to them, the pivot points on the mounts are different. The left sensor bolts on near the end of the mount while the right one bolts on in the middle of the mount. This makes their adjustment arcs completely different. Make sure you mock up each side individually! I cut, mocked, and welded again and my second mount was good to go.
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  #5  
Old June 13th, 2009, 01:41
fyrfytr1717 fyrfytr1717 is offline
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Re: THE XJ Dana 44, ABS, How-to thread (56K beware)

Now it’s time to put everything back together. Install your sensor mounts and tighten down all the bolts to the FSM recommended torque. On the left side, you’ll have to do this prior to attaching the sensor to the mount as it will block access to the nut once it is in place. Assemble all the brake hardware onto the backing plate. There’s not a lot of extra room, but as you can see, the tone ring has ample clearance above it.



Next, install your sensors and swing them into position. Insert a feeler gauge (I had good luck with a .035” steel) between the sensor and the tone ring. As you tighten the sensors down, they will actually press themselves right up against the feeler gauge. Get them snug and then pull out your feeler gauge. It’s a tight spot to work in, but easily done once you get the hang of it. You can see the feeler gauge in this picture.



When you’re done it should look something like this.



And that’s it, you’re done! Put the drums on, adjust your brakes as you normally would, put your wheels on, and take her for a test spin. Make sure to test your brakes (in a safe location) in all different stopping situations to test your sensor adjustment. High speed, slow speed, fast braking, slow braking, hard braking, and soft braking. Once you’re comfortable with those on dry pavement, give it a shot on some loose stuff to make sure the ABS is still doing its job correctly.

So there you have it. It really can be done. And it’s not that difficult. Better axle, bigger brakes, and you still have your ABS! If you’ve made it this far, I appreciate your reading my novel of a write up. I hope all of you out there that have sent me PM’s about D44 ABS find this helpful. Hopefully this will also instill some confidence in the lurkers out there that want to keep their ABS and give them the courage to finally get rid of that POS Dana 35 they’ve been worrying about for so long.

Good luck and if you have any questions about the way I’ve done this, please feel free to post up or PM me. Please don’t ask me for advice on doing this on other axles, with different brakes, etc. I really don’t know. Use my write-up as a guide and adapt it to your own application. Post up if you have some positive results. And please, please, please post up if you decide to try this on your Cro-Mo axle shafts, regardless of whether it works or not. I’d love to know as I plan on upgrading shafts eventually. So long as the flange on the back of the WMS is beefy enough I figure it should work just fine, I’ve just never looked at one up close and in person.

Enjoy!
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  #6  
Old June 13th, 2009, 02:06
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ColoradoRaptor ColoradoRaptor is offline
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Re: THE XJ Dana 44, ABS, How-to thread (56K beware)

Damn, that is a very nice write up!!!! My ABS system has already been gutted so I have no interest in this mod but WELL DONE!! Oh, this should be a sticky!!
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Old June 13th, 2009, 08:02
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Big_Al Big_Al is offline
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Re: THE XJ Dana 44, ABS, How-to thread (56K beware)

X2 ......
Quote:
that is a very nice write up!!!! My ABS system has already been gutted so I have no interest in this mod but WELL DONE!! Oh, this should be a sticky!!
....Al
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Old June 13th, 2009, 08:39
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BlueCuda BlueCuda is offline
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Re: THE XJ Dana 44, ABS, How-to thread (56K beware)

I killed my ABS system when I did the 8.8 but that is a great write up.
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  #9  
Old June 13th, 2009, 10:47
codyyy codyyy is offline
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Re: THE XJ Dana 44, ABS, How-to thread (56K beware)

I haven't gotten rid of my ABS but I don't want the D35. It actually doesn't look as bad as I thought. I think the worst part for me will either be turning those flanges or making the brackets, but turning the flanges myself would be kinda scary.
I could probably swap on disc brakes too while I'm at it and still keep the ABS. I think if it can be done on the D35 without taking the ABS off, it should go on with the 44.
Probably the worst part will be how much downtime this will be since it's my daily driver. I could probably get away with it if someone scraps an ABS equipped D35. Thanks for the write-up, I'm pretty certain I'll need this so I'll bookmark it.

Last edited by codyyy; June 13th, 2009 at 10:54.
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Old June 13th, 2009, 12:27
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FlexdXJ FlexdXJ is offline
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Re: THE XJ Dana 44, ABS, How-to thread (56K beware)

That is a good write up. Why the drums though? Do you plan on converting it to disks? I don't have ABS but i could see this being helpful for someone wanting to retain ABS function and have a stronger axle.
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Old June 13th, 2009, 13:10
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tomcat tomcat is offline
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Re: THE XJ Dana 44, ABS, How-to thread (56K beware)

Sweet writeup, i will add my version with the ZJ disk brakes when i finish it up later this week
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Old June 13th, 2009, 13:43
fyrfytr1717 fyrfytr1717 is offline
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Re: THE XJ Dana 44, ABS, How-to thread (56K beware)

Quote:
Originally Posted by ColoradoRaptor View Post
Damn, that is a very nice write up!!!! My ABS system has already been gutted so I have no interest in this mod but WELL DONE!! Oh, this should be a sticky!!
Quote:
Originally Posted by Big_Al View Post
X2 ..........Al
Quote:
Originally Posted by BlueCuda View Post
I killed my ABS system when I did the 8.8 but that is a great write up.
Glad you guys liked it, I appreciate the positive comments!
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Old June 13th, 2009, 13:48
fyrfytr1717 fyrfytr1717 is offline
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Re: THE XJ Dana 44, ABS, How-to thread (56K beware)

Quote:
Originally Posted by codyyy View Post
Probably the worst part will be how much downtime this will be since it's my daily driver. I could probably get away with it if someone scraps an ABS equipped D35. Thanks for the write-up, I'm pretty certain I'll need this so I'll bookmark it.
For the least downtime possible, pull your D35 shafts and remove the tone rings. You could go ahead and pull your sensors and mounts at the same time if you want to start working on them too. Put the shafts right back in without the rings and just drive your D35 without ABS until your D44 is ready to bolt up. Downtime should only be a couple of hours.
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Old June 13th, 2009, 14:29
fyrfytr1717 fyrfytr1717 is offline
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Re: THE XJ Dana 44, ABS, How-to thread (56K beware)

Quote:
Originally Posted by FlexdXJ View Post
That is a good write up. Why the drums though? Do you plan on converting it to disks?
I didn't want the added expense or hassle of doing the disc swap and the 10x2.5" D44 drums are an improvement over the 9" D35 drums. They'll still lock up my 33's (with the ABS disabled of course ), you just have to push a little harder on the brake pedal. I'm sure discs would be an improvement, but my drums suit my needs at this point in time. We'll see when the day comes that I bump up to 35's.
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Old June 13th, 2009, 14:30
fyrfytr1717 fyrfytr1717 is offline
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Re: THE XJ Dana 44, ABS, How-to thread (56K beware)

Quote:
Originally Posted by tomcat View Post
Sweet writeup, i will add my version with the ZJ disk brakes when i finish it up later this week
I was wondering how your project was going. Looking forward to seeing your write up.
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