Nothing Special – ’71 daily driver – trail rig build thread

[Nothing Special]

A lot of work with a little to show for it. I decided the first thing to do would be to make clearance to clock the transfer case up. The Atlas 2 transfer case has 4 sets of holes for the mounting studs. Putting the studs in different holes will rotate the 'case up or down. When I first installed the Atlas I found that it had to be clocked in the lowest position to clear the frame.

That hasn't been a huge issue with the dropped radius arm mounts because it was still higher than the arm mounts. But now that I'm going to be raising the radius arms I want to get the transfer case higher. Here's an out-of-focus side view showing the current situation. The tape measure is showing 15.5" clearance under the lowest point on the transfer case.

I started off cutting as little as I thought I could get away with, then tried fitting the transfer case in with the studs moved to the second position. I kept finding where it was hitting and gnawing off a little more metal until I could fit it in position 2. Here's the hole in the frame I ended up with...

... and here are the places where more material needs to be removed if I'm going to go any higher

I don't really want to cut much higher on the frame, and I'm a little afraid that I might need to even go through the top of the flange to get to the third position. And opening up the hole more to the front would require moving the trans cross member mounting holes which gets a little challenging. (This last picture also shows the original radius arm mounting holes above the current dropped location).

On the plus side, going up one position won't require making a new trans cross member (it would have to go below the front driveshaft rather than above if I go up another step. But on the minus side, I only gained about 1/2" under the transfer case

My original plan was to finalize where the transfer case was going to end up and then reinforce the frame where I cut it before moving on to other parts of the project. But I decided to put the transfer case on hold for now. I'm not at all sure that I want to do what it will take to go up another step, so I'll get the radius arm mounts back to stock height, get the wedges cut off the axle and rotate the pinion up to see how the front driveshaft lines up. At that point I'll see if it looks like clocking the transfer case higher will gain me enough to be worth the extra work.

 

[jmhend]

I have seen where people have to have a 2-3" body lift and modify the frame as well as the floor to get the Atlas to sit flat. Great build btw.

 

[Yeller]

If your building a crossmember it gets a little easier. You can clearance the hole in the frame for the motor mount on the drivers side 1/8” and push the tcase over enough to make clearance much easier. And yes to get flat you need a body lift or to modify the floor. I vote the floor it’s under the seat and you won’t care.

 

[sprdv1]

If your building a crossmember it gets a little easier. You can clearance the hole in the frame for the motor mount on the drivers side 1/8” and push the tcase over enough to make clearance much easier. And yes to get flat you need a body lift or to modify the floor. I vote the floor it’s under the seat and you won’t care.

Ask you how you know right

 

[Nothing Special]

I'm not necessarily going for flat, just as high as I reasonably can. I do have a body lift (~1"?), and I don't think the floor is going to be my limiting factor.

As far as moving the entire drive train over to the right, I sort of tried to do that when I first installed the Atlas. I could probably get a little more, and maybe I will try.

As far as building a cross member, I did when I installed the Atlas a few years back. With it clocked in the second position I can still use the one I already built. If I go to the third I'll need to build a new one.

For now I've moved on to other parts of this project. But I do really appreciate thoughts and suggestions here. I'll be getting back to this before the project is done.

 

[Nothing Special]

It's been a few weeks since my last post, but I haven't been idle. I just never made enough progress in a single weekend to seem to be worth an update. But now with several weekends worth of progress it seemed like a good time to add something here.

One big direction change happened in this time. I decided that I would swap a high pinion axle in. Through some other discussions I decided that it seemed likely that I would have enough clearance with my current lift. That does mean that my wife won't get the lower step-in height she was hoping for (because I'm not putting a lower lift on it now). But it did feel a lot more comfortable cutting an axle up when I still have the stock axle in its stock form. So if I screw up completely I can at least put the stock axle back in and drive it to a shop that can bail me out. Much better than possibly ending up with a Bronco with no front axle stuck in my garage!

I was able to find a complete axle (locking hub to locking hub) from a '77 F-150. But then the junk yard decided I didn't want that axle (it had some water in it) so they were preparing to send me a '78 F-150 axle instead. I REALLY didn't want that axle (where the wedges are cast as a part of the inner C, so you can't adjust angles). But they had already disassembled the '77 axle and didn't want to try to figure out how to ship me the loose parts. So they shipped me the '77 housing (knuckle to knuckle) and the complete '78 axle (locking hub to locking hub). That gives me all the parts I need, but it does give me a big heavy hunk of scrap metal I need to deal with.

After disassembling the '78 axle to get the parts I need from it, and pulling the knuckles off the '77 housing I pulled the existing front axle out. Then the next progress was cutting off the dropped radius arms mounts off. I was able to do that without damaging the stock mounts which was nice. Now I don't need to do anything to put stock mounts back on

Here's a picture I posted before, showing the dropped mount in the foreground.

And here is after cutting the dropped mount off

Then this weekend I got to work on the high pinion housing. Here it is (in back, with the stock Bronco axle in front)

I couldn't get at the inner Cs with the wedges in the way, so I cut the wedges off first. A cutoff wheel made most of that pretty easy, but the inner C was in the way to be able to cut the weld all the way. So an air chisel slowly took care of what was left.

I tried cutting the passenger's side C off next, but after trying to cut the weld away I still couldn't get it to budge. So I gave up and cut the tube off flush with the inside face of the C. Then I could use a hack saw to cut the piece of axle tube that remained in the C into several sections. I was then able to knock the sections out with a hammer and punch.

Having to "cheat" that way on the passenger's side wasn't bad because I'm going to have to cut 6" off that tube anyway. But I guess I'll only be cutting 5/8" off the driver's side so I couldn't do that side the same way. In getting the sections out of the first C I realized that I hadn't cut back into the C enough to cut through the weld penetration. So I tried to cut in deeper on the driver's side. I still wasn't holding out a lot of hope, but after cutting it I took a few swings with a big hammer and saw a faint line start to show up! It took a lot of swings, but it did come off! So now the axle looks like this.

Still a lot of work to do, but this is the part I was dreading most and it's now done!

 

[.94 OR]

Nice job.

Hadn't really thought about where the fill plug is on a hi-pinion. Looks like a good time to double check the inner axle seals to make sure they are in good shape before final assembly.

 

[Nothing Special]

Everything in the axle housing is getting replaced. This axle was outside in a junkyard and apparent;y had a little water in it, so there's some rust on the gears. But I needed to change the 3.54 gear to 4.10s and add a locker anyway. So new bearings and seals were coming for sure.

 

[Nothing Special]

.... I'm not at all sure that I want to do what it will take to (clock the transfer case) up another step, so I'll get the radius arm mounts back to stock height, get the wedges cut off the axle and rotate the pinion up to see how the front driveshaft lines up. At that point I'll see if it looks like clocking the transfer case higher will gain me enough to be worth the extra work.

I wrote that a month ago. This past weekend I got the high pinion axle housing cleaned up and shortened and I was able to put it in the Bronco to see how things lined up. With it sitting at ride height and the transfer case clocked to the second position I had only gained 1/2". But the bad thing was that mu double Cardan U-joint was going through a 26* angle at ride height. I tried at full droop and it wasn't binding, but I wasn't comfortable with that.

So I put the transfer case back to the first clocking position and tried jacking up the transmission. The limiting factor turned out to be the front driveshaft hitting my home-made trans crossmember. But the good news is that at that point I had gained another 1/4" of clearance under my transfer case and reduced my U-joint angle by about 3*.

That's as far as I got this weekend. I did modify the trans crossmember to hold it there, and I might end up going with that. But next weekend I'm going to pull the crossmember out and see if I can go any higher. If I can I'll be able to make a new crossmember to go under the front driveshaft. But that's for another day.

 

[Yeller]

Nice progress. What did that do to the rear pinion angle? Just looking ahead for you lol

 

[Nothing Special]

I have thought about that, but I won't worry about crossing that bridge just yet! I cut the perches off and welded new ones back on a decade or so ago. Worst comes to worst I can do that again.

And although I haven't put the rear driveshaft in, I'm sure that double Cardan U-joint isn't at a ridiculous angle. Although now that I'm writing that I think I will throw it in to see for sure before I lock myself in.

 

[Nothing Special]

This weekend I took the transmission crossmember out and jacked up the trans as high as I could. The transfer case hitting the floor was the limiting factor and I picked up another inch of ground clearance! That's a total gain of about 1.75" from where I started.

But the unbelievably good news was what it did to my U-joint angles. With the axle in and the Bronco sitting on its springs I tilted the axle pinion up 11* which matched the 11* angle of the driveshaft. And with the transfer case now pointing up 4* I only have a 15* total angle in the CV joint, down from 26* last week! (well, I did say "unbelievably good"). I must have read something wrong last week, because there's no way I gained 11*. But last week it looked like it would bind and this week it doesn't. So whatever the numbers, it was a big improvement. And since as bad as it looked last week it still actually did move freely, I feel very good about where it is now.

As Yeller pointed out I'm also affecting my rear driveshaft angles. The transfer case is pointing 4* down, the driveshaft is at 17*, and the pinion is pointing up at 21*. The 13* in the CV joint seems fine, but the 4* at the pinion isn't ideal. Still, with the pinion pointing up MORE than the driveshaft I actually must have had even worse before. Which reminded me that I set the pinion angle two transmissions and one transfer case ago, and when I switched from the AOD to a manual trans I ended up with the pinion pointing too high. But since I never noticed any vibration I never did anything about it. So since it was good enough before and it's better now I'm not going to worry about it unless I get vibration.

Next step is to make a new transmission crossmember to run under the front driveshaft. Once I get that locked down I can start tacking the axle together!

 

[Yeller]

Nice!

 

[Nothing Special]

A lot of time has passed since my last post. I've been busy, both on the Bronco and with other things, so keeping build threads up to date has slipped. So I'll try to catch up a little here.

I ended up making a new trans crossmember that went under the front driveshaft and held the transfer case up against the floor, so it ain't goin' no higher. That gave me 1.75" more ground clearance under the transfer case than where I started. Cutting off the radius arm mounts gained me about 4" there, so I've done pretty well on the primary goal of this project.

And I didn't need the hole in the frame I had cut so I patched that.

Raising the transfer case did poke the shift linkage up higher, now coming through the floor. So I'm going to have to re-do some stuff there.

'Nuff talking, here are some pictures.

Here is the new trans crossmember and some pics of it installed.

Here's a side view showing the new ground clearance

And here are a couple of pictures showing how close the transfer case is to the floor and how much the linkage comes up through the floor.

 

[Nothing Special]

Catching up on the axle now.

I had this thread on figuring out the track bar and bump stop brackets. And this thread on axle shafts.

Then after getting the transfer case bolted into its forever home I put the axle in, lined everything up and tacked it together. I ended up taking it to work to burn it in as my welder doesn't have the power to get decent penetration on the 1/2" thick axle tubes (at least when plugged into 120V, it should do better on 240, but I don't have that available yet).

Then after getting it cleaned up as best I could (the inside of the tubes was the biggest challenge) I got to set up gears! I'd done half of that job when I installed the OX locker a few years ago, but since I wasn't moving the pinion that time I didn't have to do the other half. This time, with the old OX going into the "new" housing with a new ring and pinion I needed to do the entire job.

If you want all of the details, I had this thread asking about the fit of the pinion nose bearing, and this thread going through the process of setting up the gears. I ended up pressing the inner pinion race in and out 3 times to adjust the shims for the pinion depth, the pinion nose bearing those 3 times plus 3 more to get the pinion preload set, and the diff went in 6 times, with several shim adjustments to get the backlash set.

The net result was 13 lb-in pinion torque-to-turn without the pinion seal, 22 lb-in total torque-to-turn without the seal (26 lb-in with the seal) and .0065" backlash. And here's the pattern

Drive side

Coast side

I'm happy with that! It took about 10 hours of work over 4 nights. But I was expecting a lot worse!

 

[sprdv1]

Nicely done sir.. Time and patience right

 

[Nothing Special]

Thank you! Time and patience are definitely the keys. If you try to hurry it (at least as a newbie) you're sunk.

 

[Nothing Special]

About a month more progress to catch up on. But first a spoiler: it's finally back on the road now! I've only been driving it for a couple of days, but I'm confident now that it will be ready for us to take on vacation in less than two weeks!

OK, back to the progress report. I got the diff cover back on and painted the axle. Then I got it hung under the Bronco and got the ball joints in.

I wasn't able to put the Bronco tie rod in as the F-150 knuckles have a bigger tapered hole. So I had to order a "conversion" tie rod that had F-150 ends on a shorter tie rod.

I ended up needing new spindles. The ones that came on the junk yard axle were way too worn at the wheel bearing seal.

The aux fuel tank finally is back in. I took it out over a year ago when I was making the driver's side rock slider and knew it would have to come out again for this.

I had to bend the shift lever for the front driveline on my Atlas transfer case. It needed to be closer to the rear stick to work with the new boot I have.

I made a sheetmetal cover for the hole in the floor where the transfer case levers come through. I had to make sort of a box on it to cover the shift tower that used to be below the floor.

The cover is painted now and I installed the boot (sorry, no pictures yet). But I do have a problem. I set up the shifter with the sticks as far back as I could get to keep them away from my leg as I drive. But the shifter boot doesn't quite let them go back that far. If the stick for the front driveline is in "high" the boot tends to pop it forward into neutral. So I need to adjust the sticks farther forward to make that work.

I also got a shifter boot on the trans. That's looking and working good (but no picture yet).

After getting it all back together I drove it to the alignment shop. Turns out I didn't do a great job hitting the numbers I wanted when I cut and turned the Dana 44 high pinion. I'm pretty good on driver's side caster at 6.5*, but I'm only at 4.5* on the passenger's side. Camber is also slightly low at 1* driver's and 0.4* passenger's. But it's driving nice! It was a little "light" right out of the alignment shop, but I added a bit of toe-in and it feels quite good now. I might try and add a little more toe-in to see if I can get it even better, but if not I can certainly live with it like it is now.

And the shop re-rebalanced my mud tires. They were rebalanced right before I drove it down to Missouri to go 'wheeling a couple years ago, but gave me a lot of vibration at some freeway speeds. I could deal with it on that trip by not driving those speeds, but it made me leery of flat-towing it where I wouldn't be able to feel if it was shaking itself apart. But it's dead smooth up to 70 mph now!

I still haven't driven it on the new front gears. I have put it in 4WD with the hubs unlocked to spin the driveline and there's no vibration or noise (at least that I can hear over these tires!). But I want to pull the rear driveshaft out to drive it in front wheel drive to break in the gears.

But it's back on the road!

 

[Nothing Special]

I got the transfer case shifter adjusted so I can put it in 4-high without the boot pushing the front stick back to neutral, so I finally have pictures of the shifters. In these pictures the transfer case is in 4-high (both sticks all the way back). Most of the time of course it will be in 2-high, with the left stick (which shifts the front driveline) one click forward (in neutral). And on the trails it's usually in 4-low (both sticks 2 clicks forward of these pictures). 2-high and especially 4-low puts the shifter for the front stick against my leg, so I would have preferred having them farther back. But I should be able to live with this.

 

[Yeller]

Looking great!

When are we going to Moab?