DIY Front Sway Bar Center Disconnect - Work in Progress

rsaunders80

Test Drive
Location
Atlanta, GA
I'm trying to engineer a solution to the front sway bar on the Nissan. You can pretty easily access the end links and disconnect them, but there isn't room to rotate the sway bar out of the way of the front suspension. Most sources agree that a center disconnect is the best option but haven't provided a way to make this happen.

Not sure if it will pan out, but I have a concept I think is worth considering and seeing what input others can provide. See attached PDF file for for the concept and note there are two pages. The idea is to cut out a section of the Xterra sway bar and weld in some splined axle segments (cut from a full size axle). We can then used compatible side-gear splines and clamping collars to connect and disconnect the sections. If this works, we should be able to access this assembly from the oil opening in the skid plate and remove one bolt to slide the assembly off the splines.

One goal was to use some generally available pieces and things I can find dimensional information about. I'll probably go to the junkyard soon and see if I can grab the following parts to start testing:
  • Xterra front sway bar (need to cut open, don't want to use mine as a test) ($30)
  • (2) GM rear axle shafts for 7.5" rear end - 26 spline (~$40 each junkyard or ebay)
  • (1) GM side gear for 7.5" rear end - 26 spline. ($22 junkyard price)
The 26 spline stuff is older but good because it's a nice dimension: 1.125" OD on the splines. Most other axles are 28 spline min and don't work with standard dimensions. Clamping collars are the key to connect/disconnect here and I can get them in a dimension that matches this diameter.

Concept Notes/Questions/TBD Items:
1. Fit-up of the axle shaft stub inside of the sway bar is TBD. Sway bar inside diameter isn't something I've found
2. Are OEM Xterra sway bars hollow? If not, a butt-joint weld will be required and likely more difficult to get straight.
3. How tight are splines inside of side gear?
4. Is sufficient clearance available between sway bar and frame for the side gear diameter (roughly 4" total).

Links:
Collar: https://www.globalindustrial.com/p/two-piece-clamping-collar-g2sc-112-b
Axle Info: https://www.markwilliams.com/axles-schmaxles.html
Ebay Axle shaft: https://www.ebay.com/itm/363930942324?hash=item54bbf97b74:g:TIoAAOSwdz9eBVnF&amdata=enc:AQAHAAAAoIc77LLDPRsgqR7FPtWexgi7J5GFE/sISUZNke+w2iKj1pxsjOxaTcVFkkuK1wu0UvOiGMfkGsqkrs7yly6qXPozJ3E0YgIx79w8deSwrwqTZ3u7FxD39EkzTERLUSY2pXeN5g461IWUJG15jllQ/k0E0rK83Gy2WIdaKpcof/iP9DGnkYh0Lue1x7bTxgoAiaZo4RDsA/LbOA8SjsHboag=|tkp:Bk9SR-zO3cfnYA

I welcome input and ideas, especially if anyone has information on the sway bar.
 

Attachments

  • Disconnectable Sway Bar.pdf
    897.5 KB · Views: 9
Last edited:

29erClan

Bought an X
Location
Meh
Looks like a fun project. I have some random thoughts...

If you cut the bar between the 2 bushing mounts it will lose axial stability under all that force and motion. It might need extra bushings, a sleeve that still contains the disconnected side without engaging the splines, something. Other wise I'd expect 2 floppy noise makers banging around down there.

The transfer case has something close. It's a sleeve that has internal and external splines that slides along the shaft to dis/engage various things. The splines have ramps/chamfers for guiding it into position when engaging. It already handles the full power of the drive train so if you can re-purpose those parts to fit, a junkyard pull might get you the parts for cheap.

I don't know if the sway bar is solid or not, haven't cut mine. Welding might have some bad effects on any spring temper or heat treat to the bar. Its job is to resist twisting without breaking so I expect it is high up on the list of stuff that matters. Being a perfectly round or straight bar doesn't really matter too much. Fitting standard parts to it accurately might require some machine or hand work.

How ever you continue your project, I'm interested to see how it goes.
 

rsaunders80

Test Drive
Location
Atlanta, GA
Thanks for the input and suggestions. A few items that are included in the updated sketches attached to this post:

- Swaybars appear to be solid from all input I've received.
- There is sufficient clearance for up to a 5" diameter side gear in line with the sway bar, so most side gears should fit without modification.
- The issue of axial stability is a good thing to consider so things don't fly around. I've added a central dowel and rubber washer between the two stub sections. Requires more fabrication overall, but helps the performance of the finished product.

Next Steps:
- Try to find some donor parts in the junkyard. TBD on when that will happen.
- Check fit-up of side gear, axle stubs, and get an idea of total length of sway bar to be cut/removed
- Determine how to best make 90-degree cuts. I planned on doing most of this with a handheld angle grinder, but that's not likely to end up with a precision cut. More of a chop-saw with a metal blade is needed, access to one TBD.
- Test fit-up prior to welding, trial welds between scrap sections to improve quality.
- Install and test!
 

Attachments

  • Disconnectable Sway Bar-V2.pdf
    978.8 KB · Views: 3

rsaunders80

Test Drive
Location
Atlanta, GA
Welp, the search for usable parts has made this process more difficult than anticipated. Apparently finding a 26-spline axle shaft used to be very common, but anymore those vehicles aren't very common. There are some, just not everywhere. In all of Atlanta I have found 2 possible vehicles. I visited one yesterday at a parts yard (1989 S10 Blazer) and got the axles/differential disassembled to find a 28-spline assembly. 1989 was one of the transition years for GM, so some vehicles have 28 splines on the rear axle and some have 26. There is one more vehicle in another yard south of town, but that's an hour drive for me so I'm holding off for now. I did manage to get a pristine sway bar off of a 2010 Xterra to use as a test subject for this fabrication, so the trip wasn't entirely wasted.

New searching has led me to some machining parts I'm inquiring about. One option may be to find a clamping collar that would work on a 28-spline diameter (1.2083") since these are still super-common. Clamping collars come in standard and metric sizes, so I'm unsure if the difference in diameters may still work if I buy a 1.25" collar. Seems reasonable that it might. Another option may be to find a splined shaft/sleeve assembly such as shown here: https://www.bare-co.com/files-pto2002-pto11 and forget the whole parts-yard approach. Pricing on something like this isn't listed, so I'm reaching out to see what can be provided. If either option looks promising I'll post back here.
 

TerryD

Total Tease
Supporting Member
Location
Covington, Va
You'll also need to run something against the inside of the day bar bushings to keep the two sections of the bar from pulling apart.

I would use a plastic washer between the bar ends instead of rubber. You'll have longer life from that part.

In the past I have considered this project myself. My decision was to get two bars and have a shoulder turned on one and a hole drilled in the other so they slip together at the disconnect location.

You'll also want the disconnect spring loaded in both the lock and unlock directions so you can actuate it (place whatever control in position) and then the sleeve can engage or disengage when the pressure is off the bar. That will simplify operation.

I was planning on a much coarser spline than you. That way there's less chance to engage in the wrong spline and be putting preload on the bar and suspension while driving.
 
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