CgAlpha's Solid Axle Swap - Step by step....

STEP 11:

SPRING OVER AXLE:

Sort of got to a stopping point on the front end (letting paint dry). So I thought I would tear into the SOA at the rear end of the truck. The SOA is a great mod for both the SAS and the Rancho IFS front lift. Many guys on this forum have already done it and I have done many SOA's myself. Of course...I'm always trying to improve things, and there are several tasks with the SOA that I felt I could do better on. There's much more to it than slapping some new perches on the axle and moving it below the springs.

The most notable thing that needs improvement is how to locate the forward spring hangers. Since you are cutting the old ones off...there is no good way to mark them. Because the leaf springs grow under load, its very difficult to get the new hangers back in the correct spot on the frame rails. My own personal H3 suffers from this miscalculation, and the shackles are laid back further than they should be. Not only does this effect the ride quality, it also positions the wheel too far aft in the fender opening. So after thinking about it...I came up with a new technique.

Before cutting off the old hangers...drop a plumb line down from the eye-bolt to the floor and make a mark. This will be the reference point for the new hangers. Once you get this point located on the floor, grab the plasma and hack off the factory hangers. The passenger side will come right off. The driver's side usually requires removal in several smaller pieces. I put a piece of 1/4" plate steel between the hanger and the fuel tank, to act as a spark shield. I find this works very well, and you don't have to drop the tank. After the rails are ground smooth, simply put a bolt thru the new hangers and loop the plumb bob around the bolt. Then locate the new hangers lining up the bob with the mark on the floor and tack the new mounts onto the frame rails. This works great, and I can't believe all the times I did the SOA without doing this (Duh).

Another tip I'll share...flip the pins that hold the spring pack together. You'll need some vise-grips and a 15mm. When flipped, the pin will face downward and drop right into the new perches. Failure to do this means you will need to drill the holes in the perches. Flipping the pin is much easier than drilling the perches...

Here's a shot test fitting the springs into the new hangers. Its hard to see but the shackles are rotated very forward. It should be difficult to get the forward bolts installed...

At this point, I like to install the axle with the perches loose. I loosely attach the spring plates and u-bolts. This allows me to rotate the nose of the diff up or down to set the pinion angle. Obviously, you want to do this with the full weight of the vehicle on the springs. Once I jack up the rear end to compress the springs...I set the pinion angle to match the t-cast output angle. Matching the two u-joints to the same angle will insure a vibe-free driveshaft. After the pinion angle is set to your liking...tack the perches on to the tubes and pull it back out. Now you can fully weld them, and do a bunch of other work before final installation. I cut the original bumps off and made some risers for the new urethane ones. I also re-purposed the original landing platforms, and welded them onto the spring plates. New brake lines for a Mazda fit perfectly but, were still a bit short. So I made an extension bracket to relocate the brake lines up higher on the diff.



I also replaced the diff vent tube with a longer one. The locker wiring can simply be un-clipped from its anchor and this will give additional length for the added droop. Shocks and sway bar are not shown here. More on that later.

STEP 12:

FINISHING UP THE REAR:

I had Patterson Driveline make a new rear shaft. They cut the original castings off the oddball metric tubing and replaced the tube with a new 3" steel tube. The new one is 1.75" longer. U-joints were good...so they are the originals.

After the axle is bolted-in, driveshaft installed, and brakelines hooked up...I put the full weight on the springs, and ONLY THEN do I tighten the spring eye bolts. If you tighten them when the springs are un-loaded, its very common this will put them in a bind and your truck will sit crooked. So always tighten your leaf springs, AFTER you get completely done and have weight on them.

Also while the axle was out, I re-geared this truck from 4.10s to 4.88s. I'm not going to go into all the specifics of a re-gear (that's a novel in itself). But its important to note a couple things. First...the ring gear bolts are reverse thread (lefty tighty). On the 8.6 10b...you must clearance the ring gear to install the crosspin, on any gears lower than 4.56. So if you install 4.88s, 5.13s, or 5.38s...you'll need to do some creative grinding on one or two of the teeth. Go gentle. Go slow. Remove no more than you need. Its important to note this does not effect the strength, as the area of the tooth you remove is outside the contact patch of the gears during operation. So its not a big deal...Speedy & Bebe turned me on to this years ago...

Now that the axle is back under the truck...I have measured and fabricated the bump stop towers. I have also measured for new shocks and sway bar ends. Lastly...new bar-pin eliminators are needed as well. These parts are on order and should be here very soon. Roughly 2-1/2" of open travel before bump contact...probably another 1-1/2" of squish after that. Droop should be draw dropping, and I cannot test that here in my shop. That needs to be done outdoors on a ramp or with a forklift.

@4speedfunk

When finished will you be posting a parts list?
You really need a video channel for this, it would be awesome.

I have many H3 vids on YouTube. Search using keyword "THORparts", and you will find a bunch of H3 mods and wheeling.

STEP 13:

IMPROV-RICATION:

As with any project like this...there will be setbacks, and adjustments. One such area that has always been an issue is "shocks". On past H3SAS's I opted for several different options...usually custom valved, reservoir equipped, and expensive. On this build, I wanted to stay on the "budget" side of the shock spectrum. That means sticking with a traditional mono-tube design, and preferably an "off-the-shelf" shock that would not require custom valving. Fox shocks offers what they call "universal" shocks. These come in various lengths, and they are valved to suit most generic applications. This line of shocks is called their IFP 2.0 series, and I had to decide between 8" and 10" stroke lengths. I am right on the edge of an 8" being too short, and a 10" being too long. Since this truck is built to (and currently sitting at) an absolute minimum height...I figured it would only go higher from here. So I chose the 10" shocks. If there is a problem with them bottoming out, I can raise the ride-height or lower the bump stops accordingly. All of Fox's universal shocks come with eye-bushing mounts on both ends, and that causes a problem with the rear shocks since the factory units use a bar-pin mount at the top.

I started off by trying some Jeep XJ (Cherokee) bar-pin-eliminators. These are for the FRONT shocks on a Cherokee but, the purpose is the same. They bolt on to the shocks without any drama but, the mounting holes are twisted 90 degrees from what the Hummer needs. The Hummer's rear shocks lean forward at a pretty good angle, too steep to try and force them with the bushing sitting sideways. They really need to be oriented so the bushing can rotate on the mounting bolt, rather than cramming the shock into place and compromising the bushing. So I needed to drill two new holes in the upper shock mounts.

I started by removing the captured nut thingy from the back side. Then I drilled the new holes and fortunately I had a small 1/4" drill bit that was about 14" long...perfect to get way up there and drill the holes. Then I re-used the metric nuts on the back side of the shock mount...also used the original stock 10mm mounting bolts. Once in place, the shock was easily leaned forward and I could located and weld the lower mounts onto the axle tubes. Also shown in these photos are the new (longer) sway bar links. After lifting the rear, its important to look closely at the sway bar position. These links act like elbows when the suspension droops. If the links are too short, they can actually straighten out and reverse rotate at full droop. Then when the suspension relaxes and returns to returns to ride height...the sway bar rotates the wrong way and...CRUNCH! Its actually a bigger issue on the T suspension, than the SUV. The T sway bar is more prone to reversing because it is bent to clear the spare tire. If you are doing a SOA...make sure to check your sway bar position. The arms of the bar should be parallel (or close) to the leaf spring angle when at ride height.



And here's a photo of the final install of the "stuff" at the pumpkin. Longer brake lines, longer vent hose, extension bracket on the diff cover, and the un-clipped locker wiring.

At this point, the rear SOA mod is complete and I'm done with the rear suspension. But, shock length, bump stop space, brake lines, sway bar, etc...will all need to be test flexed and adjustments made if necessary. Its much better to find out issues in the driveway, than on the trail! I can't do any of this until we are back on the ground. In the meantime, I will be switching my focus to the front suspension...most notably the steering. I have been fiddling with the drag link orientation, pitman arm options, and also looking at hose routing for the power-steering and ram assist. More on this topic coming soon.

Thanks 4speed. Great write up...someday...
But in the meantime: "This truck has Rocky Road rails, and they are a bit scary...not near as sturdy as the GM rails. They should work but, I will be keeping an eye on them..."
What?? Was thinking of upgrading from the GM to the Rocky Roads. Admit I have not seen them in person, are they not a tough as the GMs?

PbSlinger said:

Thanks 4speed. Great write up...someday...
But in the meantime: "This truck has Rocky Road rails, and they are a bit scary...not near as sturdy as the GM rails. They should work but, I will be keeping an eye on them..."
What?? Was thinking of upgrading from the GM to the Rocky Roads. Admit I have not seen them in person, are they not a tough as the GMs?

Click to expand...

I have the GM rock rails, and looking at the Rocky Road's they are no where near as sturdy as the GM's. The GM's were well designed and have very little flex to them due to the formed mounting brackets. The Rocky Road's on the other hand look like they'll easily bang up against the body and almost like they are designed to rely on the pinch seam of the body for upward support. The GM rails are designed specifically to give the pinch seam clearance so that it doesn't get hit in regular use. I have lifted the whole side of the H3 using my hi-lift and the GM rails and it flexed pretty minimally.

Really the only complaint I have about them is you cannot use them as a step. I have plans to add another tube to mine though to both act as a step and to help keep the side of the body away from anything that might want to jump out at it.

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Yeah the RR rails look beefy at the rails. But the brackets that connect them to the truck are a bit wimpy. They flex & bounce all over the place.
I actually don’t care for rails that stick out as far as the RRs. They do protect the side of the truck better but, they make it a tad more difficult to get in & out. And their powder coat peels off if you look at it too long.

4speedfunk said:

Yeah the RR rails look beefy at the rails. But the brackets that connect them to the truck are a bit wimpy. They flex & bounce all over the place.
I actually don’t care for rails that stick out as far as the RRs. They do protect the side of the truck better but, they make it a tad more difficult to get in & out. And their powder coat peels off if you look at it too long.

Click to expand...

This, in my opinion, is an accurate assessment of the RR’s. I have a set from a member here at a fair price when he picked up a T and moved on from a regular H3.

The RR’s work well enough but the gap at the front and back will cause problems sooner or later depending on what you wheel in; the entire railwill bend up at the square posts; and they rust quickly.

That being said they are doing their job, I’d rather see them busted and bent than the seam and quarter panel.


I like the coverage of the Schwarttzy but I have come to line the way the RR’s stick out. There are advantages when loading and unloading from the roof for sure. I figure in the nearish future I’ll finally buy a welder and make my own that look like a cross between the schwarttzys and the RR.


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The Rocky Roads do indeed flex and hit the pinch welds. So far, they've dented them in about 1mm. I'm no body expert to say if this is bad, but it hasn't resulted in any extenuating damage after 10 years of use.

I've had zero flaking of the powder coat. Yes, I've scratched through it and have found that Rustoleum Hammered Metal paint is a perft match, so I just touch them up on occasion.

I bought the RRs specifically because they do stick out further. I use them as a step getting in and out, so I find it a convenience and not an inconvenience. I will say that in mud and snow your pant leg is more likely to get soiled.

The shape of the RRs has helped me with rocks and shopping carts. No regrets on my purchase. You can see my H3 in action on the RR website, and I did not get compensation for that video. Just shows that I like them. And it shows huge weight coming down on them, the flex, and the above let's you know the final results.

I certainly understand and respect everyone that else's opinions and wanted to share mine.

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That turned out so clean and nice.

It rides like a dream! Honestly drove just as well as before in terms of ride comfort, didn't feel weird at all other than being up higher. CJ has really fine tuned the SAS method!

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Thanks all. Sorry to OP for ..."de-railing" your thread.
I'll stick with my GM rails. Didn't realize the RRs were not substantially beefier and tougher, not having seen them in person.

STEP 14:

DETAILS DETAILS DETAILS:

So if you are a Jeep guy, you can stop following this thread now. Most Jeep guys never get past the 95% complete phase. Its something I both admire, and abhor...at the same time. A Jeep guy would get to this point and simply start wheeling the hell out of his rig. The thrill of wheeling overcomes little things like alignment, crooked steering wheels, handling characteristics, or dashlights. But, we Hummer guys expect a bit more...and yes, we are somewhat spoiled by the creature comforts of our rigs. It takes a lot of extra effort to get that last 5% of completeness, to get an H3 truly "finshed". I like to get them as close to factory as I can...safe, comfortable, dependable, and with zero issues whatsoever.

The steering system on this rig is something new, and it has been a struggle to find the right combination of parts. I originally used a flat pitman arm on the Toyota box, and I reamed the hole so the 1-ton DRE sat below the pitman arm. This did not work because the castle-nut on the top, would scrape the frame rail. So rather than notch the frame rail, I ordered a dropped pitman arm, and reamed it from the top down...so the 1-ton DRE now sits above the pitman arm. Here are some shots of this mod...


After getting the steering tightened up and doing a quicky "eyeball" alignment...I bled the brakes...bled the PS system...and went for a drive. Having done a few of these by now...I have grown to expect some initial start-up issues. Leaks, dashlights, alignment issues, etc. But, on this rig...NONE OF THAT. I literally left the garage and drove it around for a week. Its very nice. Not perfect...but close...

I really love how this truck looks and drives. Its current stance is very much on par with a Rancho-lifted rig. Its 5" in the rear and 3.5" in the front. A few things came to light in the week of driving around. First...the steering box was very loose, so I have tightened up the worm gear to take some play out of it. Second...the front suspension up-travel is very short. Too short in my opinion. I am using urethane bump stops, and you can feel the axle contact them when hitting speed bumps and rail-road tracks. Also, because there is no winch on the THORparts bumper...this will surely get worse after a 100 lb. winch gets bolted on. Third...I installed 10" travel Fox IFP 2.0 shocks on all four corners as an initial test. I have the front adjustable shock towers all the way up, and the shock only has about 2" of shaft showing at ride height. So the shock is operating way out of its ideal range. As much as I hate to mess with it...I am going to raise the front end, lower the shock towers, and install 8" travel shocks. This should make for a better ride, better up and down travel, and less chance of suspension parts bottoming out on hard bumps. It will also be pre-raised for the additional weight of a winch and larger 37" tires. More on these mods later.

While test driving, I stopped by Patterson Machine and lathed a hole the stock hubcaps. This allows the Dana hub to poke thru just like it would if the factory did it...

These stock wheels (and 2" spacers) are temporary. Cg plans to install 37"s sometime soon. The 4.88 gears seem a tad low for 35" tires, so upsizing to 37"s should put the gearing about perfect.

Also worth mentioning...I used a vacuum pump to purge the PS system on this truck. I did this with a custom cap on the pump, that has a hose fitting screwed into it. With the vehicle off...and 10 inches of vacuum...I cycled the wheel lock-to-lock several times, and topped off the fluid as the air was pumped out. When I started the truck, I cycled it a few more times and then topped off the fluid one final time. During this procedure, there was ZERO screeching or screaming coming from the PS pump. It was literally the smoothest PS startup I have ever done. I highly recommend this even when working on the stock rack & pinion system. Failure to do this often results in the fluid getting whipped into a frothy, foamy, mess...and it can take days to get the air purged out...hopefully not damaging the pump from cavitation from running it this way.

Even after the bigger tires and added weight, it would be interesting to see mpg difference is now that you have locking hubs and a 2 wheel drive button. There should be a lot less drag by not using the front axle all of the time. I neve understood why they didn’t use the same transfer case and 2 wheel drive button as the Colorado? When I asked the salesman at the dealer than when I bought mine in 08 , he said because it’s a Hummer and it’s always ready for anything. To me that’s like saying I’m a man and I should always wear a condom to be ready for anything... REALLY ?!?!
That SAS conversation look amazing.

Don’t have a 2wd button but, the front driveshaft can be pulled out and the hubs unlocked. This is the “poor mans” 2wd.

MPG and Hummer should never be mentioned in the same conversation.

This will be the next thing I do, thanks for the writeup!

Wow, I never thought I would say this, but I’m seriously thinking an SAS could be interesting to me.


On a second H3 of course. Gotta build my fleet up I guess.


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One of the best write-ups I have seen. I am really considering this after finishing the linex in the spring and the ls swap. Still need to find another H3 to drive while it's all apart for months.

That is one mean looking H3. Def going to need some fender flares though to avoid tickets or people billing you for new windshields. Some white Linex for that bumper, a winch and 37's and it be nearly perfect.

I wasn't overly impressed with the RR sliders either, I thought maybe it was just me and maybe I had high expectations from all the hyperbole on their site but I still think the oem ones are better designed. Unfortunately, unless your one of the two T owners with super rare oem T sliders they are the only choice available outside of custom. They can be beefed up, just not real high on the priority list.

Thanks for the kind words. This rig is currently waiting on a few final parts to finish it off...shorter shocks, some alignment shims, and a ram assist kit.

On the sliders, I think custom ones are the way to go. You can get JK or Fj-cruiser sliders for very cheap, and then modify them to fit. This would be much easier than starting from scratch. I also think that the connecting steel between the frame and the slider rails should made from vertical plate members rather than tubing. Of all the horrible engineering on the H3, I actually think GM’s sliders are a great design and I would try to mimic them as much as possible when building something custom.

STEP 15:

SUSPENSION ADJUSTMENT:

By now I have logged probably 50-60 miles on the build, on all sorts of roads. A few things came to light and I discussed them with CgAlpha, and we decided to make some changes. First thing I noticed was that the front axle was resting less than an inch below the bump stops. This is not totally bad but, you could feel the axle hit the bumps on large obstacles (railroad tracks and speed bumps). I am using 3.5" tall progressive-rate urethane bumps. They are more firm than the stock yellow biscuits that we are used to. Considering there is currently not a winch on the THORparts bumper, AND the springs are totally new...I assumed this issue would get worse in a short amount of time. So we decided to raise the front end slightly.

Another issue I noticed was that the 10" travel front shocks were dangerously close to bottoming out while simply driving around. Because the ride height is so low, these shocks are really pushing the limit. Even with the towers all the way up, they still seemed too long for 99% of their use. Like most high-end builds, if you want to run long-travel shocks but keep the ride height low...you must extend shock hoops up into the engine bay. That's not really an option on this truck. The nice thing is that the coil spring buckets and shock towers are adjustable...and they are adjustable independent of each other. So you can raise or lower your ride height, and also increase or decrease your shock tower length. This gives the tuner a lot of options, and these pieces can be raised or lowered with a couple wrenches in about an hour. There is a series of bolt holes on the brackets and they are spaced at 3/4", so that is the increment of adjustment you have. I decided to raise the front end by one bolt hole (3/4") and shorten the shock towers by two bolt holes (1-1/2"). Then I wanted to install some shocks that have 2" less stroke.

Below are some photos of the Fox 2.0 IFP 10" travel and 8" travel, and also some pics of the suspension after the adjustment was made. The shocks are now sitting closer to mid-stroke on the shafts, and there is an added 3/4" of space at the bumpstops. Droop will be 2" less than before but, I honestly think travel is over-rated...especially on a dual-purpose rig like this. The truck still has a nice rake to it...slightly higher stance in the rear...




ALIGNMENT:

Now that all the suspension is figured out, and adjusted...I moved on to the alignment. I could probably write volumes on just this topic but, I will keep it short since anybody doing an SAS will probably want to do something similar. Starting with a plum-bob, I adjust the track bar so the front axle is centered (left to right) under the truck. Then I adjust the tie rod to set the toe-in/out. I use a piece of string for this and I run it from the rear tires forward past the front tires. The idea is to try and get the front tires running parallel and true to the rears. Caster was set on initial installation of the 3-link...3-5 degrees. The last thing I do is the camber. This is tricky on a solid axle and most shops will just stare at you like a deer in your headlights, if you roll in there with a Dana 44.

There are two basic ways to adjust the caster on a Dana 44. One is by using eccentric upper ball joint sleeves. The other is by using a tapered shim between the knuckle and the spindle. Both have pros & cons, and both do the same basic thing. GM builds its housings with 1.5" or so of camber (leaning out at the top). This is not a problem with stock 30" tires but, when you run 35" or larger tires...you will tend to get some scuffing on the outer edges of the tires, and it looks really weird too. If one side has more camber...the truck will pull to that side. I have always felt that having both sides the same, is more important than the actual amount of camber but, I try to shoot for less than a degree. I use angle gauges, levels, a carpenters square, and most of all...my eyeball. I try to get the front tires sitting true vertical with no visible amount of camber. This is hard to do and takes a lot of trial & error. But, I am so disappointed in alignment shop work that I trust myself more than I do them...especially on a solid axle.

Below is a pic of some upper ball joint bushings...one is stock (concentric) and the other is a 3/4-degree (eccentric). These come in 1/4-degree increments from 1/2-degree to 1-1/2 degree. If you need more than that, you must use an offset ball joint or use a combination of these bushings along with a tapered shim. You simply thread these into the upper ball joint hole and clock them to give you the correct offset you are looking for. Also shown is a tapered shim. This one is hard plastic, and it is a 1-1/2 degree. You can see it is cut at an angle, and depending on how you orient this on the knuckle, determines the adjustment. I prefer ball joint sleeves because they are fairly easy to change. The tapered shims however, require you to remove the hub, brakes, lockouts, and spindle....a greasy job.



STEERING WHEEL ALIGNMENT:

On most vehicles, this is not real critical. But on the H3, it is. After the caster, camber, toe-in, and ride height are all done...I adjust the drag link to get the steering wheel sitting centered. The H3 has a sensor at the base of the column, and it reads the angle of the steering wheel. It uses this to determine driver input and sends it to the Stabilitrac system, to help determine if the vehicle is in a skid or high speed drift. If the wheel is out more than approx. 30 degrees of rotation...it will set an error code. Plus...it just ain't right. I like the wheel perfectly centered they way it was intended. This can take quite a while to get perfect, and any other changes will effect it. That's why I wait until the very end to fiddle with the steering wheel alignment.

If you plan to run a ram assist, its even more critical to get the alignment and steering wheel position exactly how you want it BEFORE installing the ram. More on that next time...

walk around vid...

https://www.youtube.com/watch?v=3YJqPlLTeHo&feature=youtu.be

So do you have a parts kit with frame plates? LOL. I am settled into my new place in Missouri. Finally got my shop built late last year and it is quickly filling up with tools. About all I need is a finger brake for my press and a plasma cutter.

Just brought a high pinion dana 60 home yesterday. Now the question is what 4x4 should I buy the wife so I can start a SAS on the H3?

What t case are you gonna use?

06 H3 said:

What t case are you gonna use?

Click to expand...

Was just going to keep the stock 4:1 case. Dont plan on making a hard core wheeler, just broke way too many 44's in the past.