When the Tera disc brakes got here, I almost peed myself in excitement
This is also an optional step, as drum brakes work just fine, most of the time. I just felt the need to show off some muscle and put discs on all four corners, especially since my drums had been lacking prior to this build.
Let me tell you though, this step does not come without it's share of problems. I found out real quick that bearing races can be a big hassle. I won't go into great detail on the installation of disc brakes, since Teraflex has their own (admittedly poor) instructions on installing them, but will go over the biggest problem I had. The old passenger's side bearing race was very stubborn, and would not let go from the flange. After a couple of days of pacing, hammering, and cursing, I brought out the good ol' dremel, and used a cutoff wheel VERY CAREFULLY, slicing the bearing race across the width. It slid out like butter.
At this point was when I realized that there were brake line brackets to be added to the axle
And to my chagrin, I had already painted the axle. My advice is, if you do the same build as me, order the disc brakes at the same time as the shock mounts, or at least plan for the brake line brackets. So I got them welded up with the aid of my friend, and fellow Jeepforum member charlescho, and connected the included soft lines from the calipers to the brackets. Here it is all ready to go, except for the brake lines.
The next step is to plumb the hardlines
I bought an RE 24" brake line with distribution block for this swap. I already had one under the Jeep, but buying an extra one helped me mock up and plumb everything before I actually got under the Jeep, and saved a lot of time. I used the stock distribution block retaining bolt, minus the washer for a tight fit, to secure the block. I also used some RTV to make sure the hole in the axletube wouldn't leak under the block.
As for the lines, I bought a 72" piece, a 20" piece, and the necessary tube cutter and flare tool. Make sure the lines have standard threads, not metric. The short side of the hard lines, going from the driver's side caliper to the block, was the hardest. To get the sharp bends, I wrapped the line VERY CAREFULLY around a 19mm socket attached to a ratchet. Double check that the line was not kinked or cracked, if it is, you will have to try again with anther piece of line. For that side, I just did a sharp S-bend.
On the long side, the line will need to go through the line retainer on the passenger-side tube. This requires a double-right angle bend. From there, it is basically a straight shot over the housing, being careful to go around the vent tube which is on the top of the driver-side axletube.
Use an 11/16" open ended wrench on the soft line's connector, and a 3/8" flare-nut wrench on the hard line's connector, and tighten them well. Use the same 3/8" flare-nut wrench to connect the other end of the hard line to the distribution block. At this point, your shock mounts are ready, your disc brakes are on, your axleshafts in, and your brake lines connected. It's ready to go under the Jeep.
Installation under the Jeep:
I began by backing the Jeep into the driveway in front of the garage
This creates less distance between the axle and the truck. I jacked the pumpkin up on the D35, and put jackstands under the unibody right in front of the front leaf mount. Here's some advice for you: don't do what I did and put jackstands on a pair of old rims. It's VERY flimsy. I was lucky no one was hurt. Use blocks of wood, cinder blocks, something more sturdy.
I unbolted the driveshaft from the pinion and the shocks from the shock mounts, and after taking the wheels off, we slid the jack under the pumpkin and jacked it up just enough so the D35 was resting on it. I undid the connection of the brakeline at the unibody, and let the fluid drain into a pan. I tried to remove the e-brake from the splitter on the unibody, but then remembered that the e-brake cables would not work with the disc brakes, as they were too short. If you are running disc brakes, there are a couple options: You can use KJ cables, Teraflex's custom cables (ouch, $100!), or possibly YJ passenger side cables
. I didn't have any of these yet, so I just took the dremel to the e-brake cables, and cut them off. I still am not running an e-brake.
That just leaves two lines connected to the Dirty-35. The ABS. The scariest part of this build for me. This part caused me to read hours upon hours of literature of people arguing. Would I have to remove my lines? The ABS pump? Would I have to bend new brakelines or take it into a shop? Well, in reality, as long as you have an XJ over 1990 (or 1991, some say), there are two easy modifications you have to do.
With the pre-1990 ABS, the Bendix system would fail the entire brake system if the ABS was turned off or malfunctioned. With the post-1990, ABS fails off, and leaves a regular non-ABS system in place. Once you clip the ABS lines at the unibody close to the e-brake splitter, all you have to do is pull two relays and one fuse from under the hood in the Power Distribution Center which will kill the ABS motor, the ABS solenoid, and the ABS light in the dash. It's that simple.
(not actually a "fuse box", but the PDC)
Now back to actually putting in the Dana 44
Once there are no lines attached to the D35 anymore (you have clipped the ABS, removed the e-brake, and detached the brake line at the unibody), and the jack is under it, you can start unbolting the u-bolts. Once they are all undone, pound the u-bolts off of the axletubes, leaving the axle connected by the center pins of the leaves. Slowly lower the axle with the hydraulic jack. If the axle doesn't come loose from the leaves, just get a prybar between them and pull 'em apart. Then you can lower out the axle and move it away on the floor jack. Just simply take the 35 off of the jack and put it wherever you want (read: the trash).
Now we put the 44 on the jack, the pinion facing away from the handle, leaf perches facing up (if I had to inform you the leaf perches go upward, you shouldn't be doing this swap)
Slide the axle into place. Jack it up and make sure one of the center pins goes into one side. The good thing about these perches is the stock center pin hole is wide enough (5/8") to accept RE center pins, which usually require you to bore out the perch hole on the 35 or 8.25. Once you get one side mated to the leaf, put the u-bolts and plate on. Make sure the nuts get threaded, but DO NOT tighten them down. With the slack, you will easily be able to shimmy the other side into place, after which you can put on the u-bolts and plate for that side. Once this is done, you just have to tighten them up.
Buttoning stuff up:
Alright, so the D44 is actually under the vehicle, and the u-bolts are tightened down over the leaves. Now, we have to work on the brakes. Take the line coming from the distribution block (in my case, a stainless steel braided line), and connect it to the brake line at the unibody, where you disconnected the last one. Tighten it down using the 11/16" wrench and the 3/8" flare-nut wrench.
As for the breather tube, you will notice that the one on the D35 was connected to the bolt that held down the distribution block. This is not the case for the 44. The vent is separate from the block's bolt. Thus, you will have to pull out the bolt from the vent tube which is connected to the Jeep, and attach the vent tube to the little tube on the axletube.
Now the shocks can go on. I reused my shocks that came with my RE 4.5" lift kit, even with the clearanced shock mounts. Granted, I only have about 3" of travel, so I will be getting new shocks at some point. But these'll do for now, since I am staying on-road.
For the driveshaft, just make sure that you get new strap/bolt hardware, old stuff is pretty brittle. Take my advice, I broke the old hardware in the yoke, and had to tap it out, or buy another yoke. I just used a set of lefthanded screw-outs and it worked perfectly. Got the new hardware, and everything bolted up fine.
Finally, DOUBLE CHECK ALL WORK. I will NOT be responsible for anything that goes wrong on your rig by following my instructions.
The final tech section is bleeding the brakes
I won't go into too much detail, as you should also already know how to bleed brakes. Now without ABS, you don't have to bleed the brakes a special way, it's like a non-ABS-equipped vehicle. Start from the passenger rear, moving to the driver rear, then passenger front, and finally driver front.
Now, there is discussion on whether the proportioning valve after the master cylinder puts out enough pressure for the rear discs. Personally, I run the stock '98 cherokee one, and it seems fine. The pedal seems just about as soft as with drums, but it only takes half the distance to the floor to stop as it took with drums. What I have heard though, is that if you don't like the feel, especially on a pre-96, you should upgrade to an adjustable proportioning valve, or simply get a grand cherokee ZJ prop valve on one that came with 4-wheel discs. This should help your pedal feel. I am fine with mine, and won't change it unless something drastically wrong pops up with it.
This being probably the hardest modification I have done to date, save for maybe the SYE, I have drawn some conclusions that I hope can help others.
1. This is not your shade-tree oil change. This is a long process which could require grinding, welding, and brake work. If that's not for you, you might think about having this done somewhere, or having a more experienced friend help you (two heads can always find a solution).
2. This axle already feels stronger. It's heavier, it's quieter, it looks beefier. I am not scared of plopping 35's under this thing. I would worry about the u-joints before I worry about the axleshafts now, and that's how it should be.
3. This requires a good set of tools. A simple vehicle emergency toolbox won't do it for you. You will need some tools that are specially made. Prepare to spend easily $100 over the price of stuff for specialized tools.
Good luck, hopefully this can help someone