Solid Axle Swap
click here for the pics




Why did I do it?

A long time ago I swore up and down I wouldn’t end up doing a solid axle swap.  The independent front suspension on my 4Runner served its purpose very well for the type of 4wheeling I was doing at the time.  As the modifications started adding up, I began tackling tougher and tougher trails.  Getting a front locker helped a lot to counter the primary disadvantage of almost any IFS system – a total lack of front articulation.  However, now I’m starting to get tired of lifting tires all over the place and putting myself in a situation that, while fun to watch, can get a bit nerve wracking.

I thought about buying an older 4Runner or mini-truck with a factory solid axle so that I’d have a trail rig that I could beat on and not care as much about, but if I did that I’d be basically starting over w/ modifications.  Besides, I really like wheeling in Fort Knox.  It’s roomy, comfortable and Marley has claimed the back seat as his.  :-)

So, I was at a crossroads.  If I wanted bigger tires, I’d either have to get an IFS lift or do a SAS.  Most of the better IFS kits out there are expensive, don’t add much in the way of flex  and/or do very little to address one of the weakest points of the IFS system – the steering.  I gave some thought to the Rockstomper IFS system, but in the end it came down to the fact that a SAS would give me the flex, added beefiness and the ability to add a selectable locker that I wanted.

I held on as long as I could….but the Dark Side was too strong.   :-)
 
 
 

The “Vanilla” SAS

There were lots of ways I could have gone with my SAS.  I toyed with the idea of a coil-sprung front axle.  The coils in the rear flex very well, so why not?  Well, in the end I decided to go with a “plain ole” SAS.  No re-inventing the wheel for me.  I drive my 4Runner on the road a lot, so if I was going to do it, I wanted to do it right, with tried and true components.  The parts list for my SAS reads like a lot of the other SAS’s out there:

One thing you may notice is that I only went with a 3” lift spring.  Some will try to tell you that you may have clearance problems with the Hy-Steer system with less than 4” lift springs, but I don’t understand why.  Clearance problems would happen when you stuff a tire.  If the axle is fully compressed and nearing the bumpstops, what difference does it make if it’s a 3” or a 4” lift spring?  Anyway, I chose the 3” springs because when coupled with the 1” drop spring hanger kit, it would give me 4” of overall lift.  That way I could just toss in some 2.5” spacers on top of my 1.5” lift Downey coils and hopefully be level.

For the installation of my SAS, I chose to go with my good friends Lance and Scott with Lobster Fabrications.  Major thanks also goes to John Smith, who came along for the weekend to help out.  I won’t really go into the real details of the installation since that’s all been done pretty well right here, but here’s what I did and why.
 
 
 

IFS Removal

I arrived at the Lobster Fabrications shop late in the evening on Friday.  Lance was just finishing up the rebuild of my new front axle when I pulled in.  We unloaded some tires I had picked up on the way for Lance and when John arrived we pulled Fort Knox into the shop.

Removal of the IFS is a relatively simple process.  I won’t go into much detail here, but basically, if it’s related to the front suspension or steering linkage – remove it.  A few shots with Lance’s plasma cutter and all the brackets were on the floor.  Since it was getting late and nobody felt like grinding, we called it a night.

Grinding sucks.  There’s no way around it.  John and I went at the frame with grinders for hours until the frame was nice and smooth, then primed and painted the frame after Lance welded in some plate over the open motor mounts.  Once that was complete, we were ready to start installing my new suspension!
 
 
 

Hanging the Springs and Axle

After positioning the jigs for the shackle hangers on the frame, Lance cut out the holes with the plasma cutter and cutting torch.  The shackle tubes were inserted and tack welded in place.  We then hung the spring hanger bracket on the IFS crossmember with the tabs that All-Pro provided and took some measurements.  “Measure 8 times, weld once...” seems to be Lance’s motto, which is fine by me since you definitely want to get these things right the first time.  Once we were all satisfied that everything was straight, Lance went to work with the Mig welder.  With the hangers in place, it was a simple matter of bolting everything up!  Springs….axle…u-bolt flip kit….hy-steer….calipers….voila!  As I said before, if you want a good set of instructions on installing a SAS, check here.  There is very little that is out of the ordinary about my SAS.

After a trip to town to replace an accidentally cut hard brake line, we finished up bolting and welding on all the SAS components and decided to tackle the task of adapting the ARB bull bar to fit with the new front crossmember.  This is where Lance’s fabrication skills came into play.
 
 
 

Adapting the ARB to Fit With the SAS

The mounting system for an ARB is extremely strong due to the fact that it bolts directly to the IFS frame crossmember in several places.  Unfortunately, this is what makes it a pain to adapt to fit with a SAS, since you must weld the spring hanger to the crossmember.  Adding to the difficulty, I wanted to raise the ARB an inch or so to eliminate the gap that had been created when I put on a 1” body lift.

We started by cutting off parts of the ARB that obviously wouldn’t work with the SAS.  We then test fit the bumper on the truck to see how we could mount it securely.  It was decided that we would mount it very similar to how it was mounted before, except it would bolt on underneath the new spring hanger.  We took measurements and cut a piece of 90 degree plate to extend the ARB’s crossmember mount to below the new crossmember and welded it onto the bumper.  We then drilled holes through this plate so that the bumper could be bolted on through the holes used to align the spring hanger.  Some L-shaped tabs were then welded onto the back of the spring hanger so that the bumper could be bolted on from underneath.  Lance then made some extensions for the side mounts of the ARB (where it bolts to the stock bumper brackets) so that the bumper could be raised.  Once the mounting system was complete, we bolted up the ARB and the SAS was essentially done!  All that was left was to relocated the crossover pipe for my headers so that a front driveshaft would fit, and to get a front driveshaft.
 
 
 

Finishing Up the SAS

The task of re-routing my crossover pipe for the headers was taken on by the local Midas and overall, I’m pretty pleased.  The crossover now extends behind the transfer case and hooks in just in front of the oxygen sensor.  Hopefully I will have enough room to get the t-case out when I get a Crawler.

For the front driveshaft, I gave Jesse at High Angle Driveline a call.  I gave him the flange-to-flange measurement and he built a heavy duty “Rock Crawler” front shaft for me with u-joints on either end.  A CV shaft would’ve been preferable, but unfortunately (?) with the amount of flex I have up front, a non-CV shaft had to be used to accommodate the amount of slip spline necessary for the amount of travel.  The front shaft works great, but has a bit of wobble to it above trail speeds.

For shocks up front I tried a set of 10” body Bilsteins.  I decided they were too long when they kept bottoming out on the trail (and even on speed bumps), so I switched to a slightly shorter shock, the Doetsch Tech Pre-Runner 8336’s (the same shocks I have on the rear).  These fit perfectly as they bottom out on their built-in bumpstop at the same time the suspension bottoms out on its bumpstops.
 
 
 

Rear Suspension

In order to level the truck in the rear (or at least get close), I chose to use All-Pro’s 2.5” coil spacers, which added to my 1.5” Downey coils should give me 4” of lift, roughly equal to what I have up front.  Due to the fixed length of the suspension links in the coil sprung rear suspension, this lift would move my axle forward somewhat.  In order to re-center the axle, I chose to use the All-Pro upper and lower suspension links.  These links are longer than stock to move the axle back where it is supposed to be.  The “Johnny Joints” in these links also help to alleviate some of the torsional stresses that a 4” lift can place on the suspension link connections.  Installation was very straightforward.  Just remove the old links and install the new ones.  After installation of the rear shocks, the rear was complete.  Easy…durable….super-flexy.

Why not convert to leaves?  I see no reason to convert to leaf springs in the rear unless you want more than 4” or so of lift.  With the spacers and links in place, the coil sprung rear suspension on 2nd (or 3rd) Generation 4Runners rides great and works extremely well off-road.  I really don’t think I would gain any flex by converting to leaves.  In fact, I think the coils flex better than the leaf sprung suspensions.  I have heard that lifts larger than 4” with coils get a little squirrelly.  So if you want to run huge tires (bigger than 35’s), then maybe a leaf spring conversion for the rear would be in order, but if a 4” lift is all you need, stick with the coils!
 
 
 

Overall Impressions

So far I am VERY pleased with how my SAS turned out.  The Alcans ride great and flex awesome.  There are still a few minor issues I could address, but nothing major.  Would I do anything different, having done it this way?  I can honestly say I would probably do just about everything the same.  Sure it would be nice to have a high pinion diff, but I like being able to swap diffs front to rear or vice versa if the need were to arise.

Now to see how it performs on the trails!
 

SAS Pictures
 
 
 


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