Outback Axle Swap Notes (320S)

OpenSky

I just finished putting an Outback axle on our 2016 320S, and thought I'd share a few notes on the process for others who may wish to do the same

We had planned to buy an Outback for the ground clearance, but got a screaming deal on a barely used 320S we couldn't pass on.  After dragging the spare tire across numerous gas station curb ramps on the Great Eclipse Expedition of 2017, we knew an Outback axle was still something we needed.

1.  Procurement.  Order the axle from nuCamp.  They will give you the part number so you can have a Dexter dealer order it, but I'm pretty confident you'll like the nuCamp price better.  If you are having a shop install the axle, pick the shop before you order the axle, and have it shipped to the shop.  The axle weighs over 100 lbs and is quite awkward to handle.

2.  Axle handling.  Before that axle arrives, make sure you have a place to park it, and a means to get it there.  You need a furniture dolly ($15 at Harbor Freight if you don't have one), and a 2x4" or 2x6" cut to 56" length.   The 2x4 lays on top of the dolly, and the axle will sit with the torque-tube/cross-member on the dolly, and the swing arms of the axle sitting on the ends of the 2x4.   You get it there by lifting one end at a time, with a helper to keep the dolly from moving on you.

3.  Axle receipt.  When the axle gets dropped off, inspect for damage.  It is shipped in the open, bubble wrap around the brakes but no other protection.  Note it *naturally* has a slight bend (crease) in the middle, probably for wheel camber.  On our axle, one of the EZ-lube hub caps had been smashed (probably on delivery, they stood it up on the hubcap next to the front door!), and the little nylon loop on the left brake backing plate (to hold the brake wires) was missing.  While inspecting, clean off the shipping labels, but leave the white Dexter sticker in the middle of the cross-member, where the serial number is printed.

4.  Tools.  Besides the dolly and 2x4, you'll need a floor jack and a motorcycle jack.  (I'd planned to do it with two floor jacks, but a friend loaned me a motorcycle jack, and I'd now be a little fearful of using two floor jacks).  MOST IMPORTANT:  You need 3-4 jackstands (1.5 tons or better).  DO NOT TRUST the stabilizing jacks to carry the weight of the trailer when you are working around and under it.   You'll need two more 2x4s cut to span the motorcycle jack (or the two floor jacks to approximately level the Outback axle (front-to-back) when jacking it into position   To remove the belly cover, you'll need a 3/8" socket, and a short extension is needed to remove the screw clamping the fresh water drain.  A utility knife is required to cut the sealant around the AC condensate drain.  Axle removal requires 3/4" wrenches.  You'll need a ratchet, a breaker bar, and a combination wrench.  Additionally, you'll need a crow-bar/pry bar to separate the axle from the frame (besides the bolts, there is a slight interference fit.)   Removal of the spare tire mount requires a 9/16" socket, and we needed a 13/16" wrench and extension to remove the spare tire from the bracket.  For the brakes you'll need wire cutters, strippers, and a good-quality crimping tool suitable for the crimps you'll use for the brake wires. 

5.  Supplies.  Besides the axle, you'll need about 12' of 14 or 16 gauge wire (I used 14 gauge, but recommend 16 gauge, since that is what is on the axle and the trailer) for the brake wire cross-over.  The original axle has the cross-over wire integrated (it runs through the center of the torque tube).  The Outback axle does not.   You'll also need appropriate crimps for the brake wires.  It appears Pleasant Valley used "Hydralink" one-sided multiwire heat-sealing connectors, but I had poor luck with these and reverted to heat-shrinkable butt splices and liquid electrical tape.   Because you are running new wires across the belly, you'll also want zip ties and some adhesive zip-tie mounts.  To mark the belly cover mounting strips, you'll want some masking tape and a Sharpie pen.  You'll also want zip locks or another suitable container for hardware.  Finally, you'll need some sealant to reseal the condensate drain. 

6.  Staging the work area.  Locate the trailer on a hard level surface for the project.  You'll be moving the old axle out and bringing the new axle in under the back of the trailer, so you'll need about a 6'x6' clear area behind the trailer for this maneuvering.   Drain the fresh water tank; the petcock needs to be in the open position to remove the clamp.  While the trailer is still on the wheels, crack the wheel nuts loose.  (Don't remove them yet.)

7.  Jack the trailer TO THE FULL HEIGHT as prescribed in the owners manual.  You can use the stabilizing jacks as described (or your floor jack), but you should get the trailer as high as practical (stabilizing jacks straight up and down).  If you use a floor jack, DO NOT ALLOW the stabilizing jacks to be side-loaded at all (tilted) - they will fail!   PLACE YOUR JACKSTANDS under the frame!  The jackstands should be placed under the aft cross-member, just inboard of the frame rails. 

8.  Belly cover removal.  With the trailer jacked and supported by jackstands (and, as backup the stabilizing jacks), remove the spare, and the spare tire bracket (those bolts will do serious damage to your head!)   There are 7 metal strips around the periphery of the frame holding the belly cover on.  Put some masking tape on each of these, and label with position ("Left Side, Rear") and orientation ("Forward ->").   Start removing the screws holding the strips and cover in place.  There are two lines of 3 screws with washers in cross-members.  I don't know if there is a best order for removal, but I'd suggest removing the screw at the drain petcock first, then working front to back.  Once all the screws are removed, you'll need to cut the sealant around the condensate drain (be careful to not cut the drain tube, nor the coroplast belly cover.)  The axle flanges do extend under the cover so you'll need to slide or bend the cover a bit to remove it.

9.  Cut the brake wires.  If your axle has the cross-over wires in the axle, you'll only need to cut the wires on the right side.  Cut right at the crimp, so you don't loose much wire.

10.  Loosen the bolts holding the axle to the frame.   4 Grade-8 1/2"x1-1/4" bolts per side, 6 MCX washers.  Leave the bolts in place - the axle is hanging on them!.

11.  Roll your motorcycle jack into place from behind, centered laterally under the axle.  Place the 56" 2x4 across it, and jack it into position, with the 2x4 just barely forward of the hub (you noted the proper position of the 2x4 when you were handling your new axle).  DO NOT JACK the trailer off the JACKSTANDS, just get the jack against the axle.  

12.  Finish removing the wheels, and move them out of the way.

13.  Pull the axle bolts and washers out, noting the positions of the washers.  Drop the jack slightly (< 1").  If the axle doesn't drop (it won't), you'll need to give it a hand.  Use the crowbar between the lower axle mounting flange and the frame.  It shouldn't take much force (although you'll probably need to do it both sides of the trailer), and the axle will drop onto the jack.  Lower the jack to the bottom position.

14.  Roll the axle aft towards (close to) your rear jackstands.  Lift the trailer slightly with your floor jack, place jackstands just forward of the where the axle is now located.  These jackstands MUST be aft of the center of mass of the trailer - that means they should be aligned with the BACK lip of the wheel cutout.  With these jackstands positioned, you should be able to drop the BACK jackstands, and perhaps slightly lower the rear stabilizing jacks (they are your backup).  Lower the trailer onto the forward jackstands you just placed, and ensure they are carrying the weight of the trailer. 

15.  Once satisfied that the weight is on those jackstands, you can raise the stabilizing jacks, pull the motorcycle jack with axle out from under the trailer, and relower the stabilizing (backup) jacks.

16.  Congratulations!  you are half-way done.

17.  Swap the axle positions, putting the Outback axle on the motorcycle jack.  As noted earlier, you'll need a couple of extra 2x4s under the torque-tube to make the axle approximately level.  Center the motorcycle jack and axle laterally under the trailer so you'll be able to roll it forward into position.

18.  Raise the rear stabilizing (backup) jacks, and roll the axle forward under the trailer, up almost to but not touching the jackstands.  Drop the stabilizing jacks, lift the rear of the trailer slightly with the floor jack, and place jackstands behind the axle, under that rear cross-member.   Lower the forward jackstands, then lower the trailer onto the rear jackstands.

19.  With the trailer on the rear jackstands, you can remove the forward jackstands and roll the axle into position.   Slowly lift the axle into position.  You'll probably need to adjust position slightly as you lift it.  Stop when either the axle flange hits the bottom of the trailer (because the axle isn't quite level) or one bolt hole is aligned.

20.  Insert a bolt on each side if you can.  As necessary, use your floor jack under one end of the axle (swing arm or mounting flange) as necessary to adjust the axle position to align the bolt holes.  Once the second bolt is inserted on a side, very little motion is necessary.   Put a nut on each bolt (just to keep it in place) each time you get one inserted.

21.  Once all the bolts are installed, install all washers and nuts as you removed them from the original axle.   Torque them in place.

22.  Install the wheels and tires  (you may choose to delay this; I wanted them on as quickly as possible since I'm paranoid a jack will fail).  You'll torque the nuts once the weight is on the wheels.

23.  Run two wires (16 gauge or 14 gauge) for the brakes across the aluminum cross-member just aft of the axle.  There are large holes in the frame for the wires to run through.   There should be at least one foot of extra wire on either side of the frame rails.   Using zip ties and adhesive mounts, anchor the wires to the cross-member in a position where they will not be pinched by the belly cover, or abraided by the screws which hold that cover.  Practically, this means anchor them to the backside of the angle-aluminum.

24.  Crimp, seal, and dress the wire connections at the left wheel.

25.  Crimp, seal, and dress the wire connections at the right wheel. Note that here you have to connect splice two sets of three wires;  the brake magnet, the trailer brake line, and the cross-over.  To make this easy working under the trailer, I fabricated two "V" harnesses with two wires and three butt-splices each on the bench, then installed under the trailer (this mean each crimp only had one wire in it, except for one that was done on the bench.)

26.  Replace the belly cover.  I found it easiest to do the cross-members first, then work from front to back with the edge strips.   To get the condensate drain tube back through the belly cover, you'll probably need to reach through the belly cover hole with needle-nose pliers, pinch the end of the hose and pull it through.

27.  Seal the condensate drain.

28.  Reinstall the spare, if you are keeping it under the trailer.  (We moved ours to the tongue.)

29.  Lower the trailer to the ground.  Torque the wheel nuts and the axle nuts. 

30.  Hook it up to your tow vehicle and make sure the brake controller recognizes the axle.  Then take it for a slow drive and adjust the brake force as needed.

31.  Go camp places that you couldn't get to with the standard axle.

jkjenn

Nothing like a cliffhanger!

You are on your way to a fantastic write up!

OpenSky

Sorry.  The forum got confused in the middle, posted half the write-up, and I had to finish with an error message popping up every 30 seconds or so.  But I *think* I finished the write up.

It took me about two weeks of an hour or two every day or two to get the job done, but much time was spent changing plans, getting parts and tools, etc.  I think it could be done in about 2-4 hours if you have everything on hand.

dragonsdofly

@OpenSky, wow!

Sharon_is_SAM

Thanks for taking the time to do this.  Excellent detail.

OpenSky

btw, I have the original axle advertised for sale on Craigslist and the tnttt forum.  (Probably not too many people on this forum looking to put a standard axle in an Outback.)  Not much interest, probably because it doesn't work with the standard welded-rectangular tube frame. 

Istokpoga

Great write-up!  Reviving this thread with a question. You mentioned "adjusting the new axle position to align the bolt holes". Did you note any fore/aft adjustment for the axle on either side for alignment? 
I ask as we recently purchased a lightly used, well maintained 2017 320S. I have noticed, without yet measuring accurately, the right wheel is apparently about 1.25 - 1.5" "ahead" of the left. It is visible in the fender wells and frame, and I can see the crabbing effect in my mirrors. It is not likely off enough to ever hurt anything, and it doesn't affect handling nor reversing, but it's something I see. 
Thanks for this thread! 

OpenSky

There is no ability to align the axle - the reference to alignment in the post is simply to get the bolt holes aligned between the frame and the axle.  The axle position is pretty much set by holes in the frame and the mounting flange on the axle.  See photos below.  One could not simply drill new (or enlarge existing) holes to realign, because the lower mounting holes are in dimples in both the frame and flange.

There might be 1/4" of "adjustability" simply due to the clearance on the holes, but certainly not an inch or more.

Istokpoga

Thanks for the response and additional pics. I was suspecting as much looking at it from the outside, though I was hopeful. 
At this point I'm going to assume the frame is straight and the alignment issue is with the body on the frame. I've pulled it about 3,000 miles and have no detectable tire wear problems so I think this is something I need to learn to ignore. 
The upside is we've had a great time with this trailer since the purchase this summer!

cafyrman

I'm looking at doing the same thing to my 400 for the same reasons.  Found a deal I couldn't pass up on an early '18 non-Boondock 400.

Did you find any issues with fender clearance due to the different axle swing?  In other words, would the mounting spots for a factory Boondock/Outback be different?

What did you use for tires/wheels?

OpenSky

No issues with fender clearance, except that you need to slightly angle the tire (toe-in) when putting it on/takeing it off (to clear the fender at the front).  Once installed, it does not interfere.

We did not replace the tires and wheels - reused the ones which were on the original axle.

Excepting the tires/wheels, this matches the 320S Outback axle configuration - same axle, mounts in the same location on the frame.

Fwammy

How do I find someone that can do this for me? I honestly don't have the skilz or time