How I did it! (that's overused!)
Well now that I'm snowed in with the approaching blizzard I thought I'd post what we did to install the Wrangler D30 into my son's '84 BII. I'll put up some links showing the mounts I made. I still have to post the pics of the conversion we did last week going from spring under to over, that corrected some problems and greatly softened the ride too.
To give a back ground, we got the BII as a sickly 2.8 with a 3 speed C5 auto, what a dog. It already had 31's and an old Rancho 4" lift. The 2.8 was yanked and the auto went into a V8 conversion on another '85 BII. Another 2.8 with Duraspark and a 350 CFM Motorcraft and a 5 speed went back in. After going through the frustrations of a new teenage driver trying to wheel a carb, a 2.9 FI engine was swapped in (a 4.0 is waiting in the shed). The gears were finally swapped out from 3.73's to 4.56's with a Detroit in rear and a very rare LSD for the D28 in front. It wheeled ok, but had a reputaion of looking like a dog peeing because it would constantly lift wheels, a lot!
http://www.calvaryefree.org/4wheel/05DecSG/pages/05_SGDec039.htm http://www.calvaryefree.org/4wheel/05DecSG/pages/05_SGDec053.htm We had done a '89 BII long arm with a 35 for another BII in the past and was not pleased with the results for the $$ spent on the kit for the TTB long arms. That brings me to the straight axle conversion, or SAS. At first we thought about using a Jeep axle from a Cherokee using a long arm kit such as from Rubicon Express. After talking with folks that had done this, it was found that the BII had to have a substancial lift or the top control arm mounts would hit the BII cross member when flexed. That left a Wrangler D30 from a '87 to '95 YJ Wrangler. The YJ's frame is wider that the BII though so mounts from the YJ frame can not be used, that required some thought about how to mount the springs part way outboard. Here is a link to the mount pics, although they have changed a bit since the final install.
http://i65.photobucket.com/albums/h228/cherokeenut/bronco pics/P1010260.jpg these are Ranger rear spring rear frame mounts available from Ford welded to heavy angle steel. Here are the finished mounts for the rear of the front springs, although more welding was done later.
http://i65.photobucket.com/albums/h228/cherokeenut/bronco pics/P1010261.jpg Here are the rear mounts bolted in place.
http://i65.photobucket.com/albums/h228/cherokeenut/bronco pics/frontmount.jpg The front mount actually took less thought and produced a much needed cross member for the front. BII's and Rangers have a very weak frame forward of the engine cross member, when the TTB is removed the member under the trans goes too. This fabed cross member/front spring mount greatly strengthens the front frame.
http://i65.photobucket.com/albums/h228/cherokeenut/bronco pics/P1010262.jpg Here is the cross member bolted in place.
http://i65.photobucket.com/albums/h228/cherokeenut/bronco pics/rearmount.jpg As you can see we used Revolver Shackles in front, but they were swapped out with my son's '88 XJ because the XJ need less rear lift and the BII needed more front lift, yes they are just XJ rear shackles. By the way, Revolvers are perfectly safe for front use, they only open up when flexing not on normal road use. As it rurned out, the BII sway bar is almost exactly as wide as the YJ's, so a pair of YJ sway bar disconnects were used. They line up perfectly. The BII brake lines (braided steel) had to be ground a bit on the ends to match up to the flat alignment edge on the Jeep calipers. The YJ shocks even fit perfectly, we used 4" lift shocks. As it turns out the YJ mounts are spaced about right too so that the shocks are almost straight up and down. Even the drive shaft fit better than the D28 lifted did. Using the D28 the boot would pop off of the T-case, showing that the shaft was too short with a 4" lift. The u-joint fits perfectly into the D30 yoke. Here's a tip, throw away the stupid Ford Torx strap bolts and use the smaller hex head Jeep bolts, what was Ford thinking. The drive shaft is now the perfect length, very important since it has a short yoke that goes into the t-case. The steering presented the only real challenge, as the pitman arm for the BII uses a larger hole for the tie rod that the YJ uses. Plus the splines are not machined at the same clocking as the YJ's arm. I don't have a picture but ended up using a YJ dropped pitman arm, and ground out the 4 aligning teeth in the large hole with a die grinder so that the arm can be clocked correctly. Now, the YJ arm large hole isn't as large as the BII arm either, but I was able to get the pitman arm on enough so that the lock washer is on and the nut is almost all the way on. The pitman shaft comes right to the end of the nut. Several thousand miles have shown that the arm isn't going to loosen. Here is a pic of the final assembly.
http://i65.photobucket.com/albums/h228/cherokeenut/bronco pics/Thewayitshouldhavebeen.jpg Here is a pic of the BII finally sitting down for the first time.
http://i65.photobucket.com/albums/h228/cherokeenut/bronco pics/P1010263.jpg Here are some pics of the BII being flexed using "forkie", the trail pics still need to get posted to my site yet.
http://i65.photobucket.com/albums/h228/cherokeenut/bronco pics/tazflex.jpg http://i65.photobucket.com/albums/h228/cherokeenut/bronco pics/rightfrontbronco.jpg Some things were changed later, the steel rims were not going to work as the D30 is about 1" wider on each side, this put the tires into the fenders, so stock BII/Explorer aluminum rims were used on the 31's. And as said earlier the shackles are now solid long length XJ units. The rear axle is now a drum brake Explorer 8.8 with 4.56's and a Powertrax no-slip locker, the D30 has 4.56's and a Detoit Truetrack. When running a Truetrac you MUST NOT use the axle disconnect that the YJ D30 uses, the Trutrac will be destroyed. The YJ D30 uses the small 260 axle u-joints, so '97 and later TJ or XJ axles (or '87 and up XJ ABS axles) were used that have the big 297 joints. This and a kit from Randy's Ring and pinion were used to convert the right side axle from the 2 peice disconnect axle to a one peice unit. The front has no vibrations at all at high speed so we'll leave it this way even if we later go to a selectable locker. I'll post pics of the same trail but with the new axle, the BII is pretty much level, but with a huge amount of flex and no tires in the air on those very same moguls! Like I mentioned, we have since done a springover conversion, as the Rubicon Express 4" springs sagged about 1" after the Duff winch bumper and winch were installed. Also, the steering was a bit mushy with the lifted springs, not bad but the stock flat springs helped greatly. As a note, your BII will not have the nice crisp steering it had, but you'll get use to it. It just feels like driving CJ.
DISCLAIMER!!!!!!!!!!!!!!!!!!!!!!!!!!
I will NOT be responsible if this does not work for you, the work here was purely an experiment. I'm a shop owner with many many years of experience, you are most likey not. I offer this as an example of what was done, you may follow at completely your own risk.