Sway bar disconnect (1 Viewer)

[Photoman]

Here is a sway bar disconnect I fabbed up. The parts are readily available tractor parts. The shafts are standard tractor PTO shafts and the coupler is from a driveshaft yoke. One shaft I used came from the gear box of a John Deere bush hog so like I said, standard stuff. All can be purchased from places like Tractor Supply. The way it works is you just squeeze the spring loaded locking pin and slide the coupler over. One position locks the sway bar for normal operation and the other allows it to twist freely. One thing will be is the cruiser will have to be in a neutral position to lock the sway bar; otherwise one side could be under pressure and the other side not. I had considered putting an air operated
spring loaded piston setup on. That way I could just hit a button from inside and it would lock/unlock without climbing under the cruiser but I don’t mind getting a little dirty. I did not do the final installation on the sway bar yet for a couple of reasons. One is I have a heavy duty sway bar on the cruiser
now which is a different diameter than the stock one and I don’t know which one I want to put it on. Also, I want to sleep on how exactly I want to make the connection. I don’t like to weld on something that is made springy to twist so I have several other ways I have thought of. Anyway, the first pic is of the basic parts.

Bill

 

[Photoman]

Locked position

 

[Photoman]

Unlocked

 

[Photoman]

Location in sway bar

 

[Photoman]

Closeup unlocked

 

[Junk]

That looks great Photo.

Also nice anvil!

Is your plan just to let the sway bar dangle then when disconnected; or are you going to make a quick release to take the whole thing off. If you take it off, when on your trips then of course, where would you put it?

Looks great. You definitely get some award for not accepting that things can't be done.

 

[Beowulf]

Junk,
It appears that the sway bar will be built to rotate in that device kinda like an open diff when the sway bar "locker" is disengaged. The great part of that design is that there is nothing dangling and when the lock is re-engaged, the sway bar functions normally.
-B-

 

[tucker74]

I don't think the idea is to take a piece out Junk - it's to allow the swaybar to rotate freely in place...negating the effect of a swaybar when disengaged...

Tucker

 

[PHAEDRUS]

I tried to figure out how to do this and could not so kudos to you photo. what stopped me was the spirng steel and not knowing how it would react while welding. also wanted to come across a spare before I cut mine in half. I really like the tractor splines though great idea as usual bill.
Dave

 

[Curran]

Bill, that's sweet!
Are you worried about effectively shortening the spring (torsional length of the sway bar) by splicing the PTO parts into it? It could actually work out beneficially by firming up the sway bars when locked.

Curran

 

[VZLAFZJ80]

Really nice job!!! It’s sweet!

One question. How hard do you think it is going to be to engage it back to the lock position? Since it would only lock properly one way, the truck must be seating straight, right?! Do you think this might be a problem?

 

[Photoman]

Thanks guys! As usual you are really on top of the way things work. As far as the concern for locking it back up; that was why I used hex stock for the ends. That way I can fudge it a bit with a wrench or two to get the splines to line up if I have to.
Two other ways I thought of for connecting to the sway bar instead of welding is to drill through the hex and sway bar and use one or two spring pins. The other way I am favoring is to drill through and press in either a piece of drill rod or using a large old fashioned hot rivet and peen it over. In other words something tight. Maybe combine it with some JB Weld or something. As with any first attempt I am concerned that the whole thing may not hold up. With many twists I don't know what the life will be of the metal to metal. I will say that that metal was EXTREMELY hard. I don't know what the Rockwell number was but I ruined quite a few tools turning it. Wish the whole thing could have been more heavy duty but I was limited by the used parts. Also, thinking of adding a grease fitting for the center twisty part. Also I don't think there would be a problem with welding one end. Any thoughts? Oh, and I realize I have to be very careful when I cut the bar to make sure it ends up back in alignment.


Bill

 

[PHAEDRUS]

This might sound a little out there but have you thought of using a really mild grade stick electrode (ie E6010) the thought being the carbon zone around the union will be smaller due to lighter heat input. along the same lines a preheat to 3-400 degrees might be beneficial as well.
Dave

 

[IdahoDoug]

Bill,

A few years back, I was looking into a swaybar disconnect for another full size Montero/Pajero I had. Several different designs were considered and I spoke with a company now defunct that made such a part for Wranglers. Then I spoke to my brother in law who's a suspension engineer for Visteon about forces, etc and got some news that kinda made me give up the idea.

He told me the peak forces on the front anti sway bar for a comparable vehicle like the Expedition exceed 11,000 lbs-ft. That's a lot of beans, indeed, and I considered the downside of a failure on a curve with the vehicle laden or perhaps while towing our boat. I don't easily shy away from a challenge, but this gave me pause simply because of the amount of force at work. Clearly, your forces will be much higher with a HD model and the greater weight of your rig.

After doing this, I then did careful measurements on the Montero to see how much the swaybar limited articulation. I was surprised to find the articulation measurements were within 3/4 of an inch on this IFS vehicle. This is in now way meant as a comparison to a completely different rig like the 80 and I suspect you also have some mods on yours that may make the articulation more meaningful. But the safety aspects of the front sway bar in particular (more critical than the rear) makes doing actual measurements worthwhile to see what you'll gain. If you've already done this I'm also interested in knowing what the numbers would be. Due to your thoroughness on other projects it would not surprise me to know you have, BTW.

DougM

 

[Cube Dweller]

I'd be concerned about the pin method to fasten the coupling to the sway bar. Each pin would be in double shear, but I'd be concerned about the holes in both the sway bar and the coupling creating a stress riser in loading situation where torque is applied in both directions constantly. It would be interesting to estimate the torsional load on the sway bar when cruising down the road at 70 mph and slamming into a pothole.....

Hardened dowel pins might fail catastrophically- in a situation Doug mentions above, could be bad. Maybe a grade 8 allen head cap screw with a precision ground shoulder would work.

I'd TIG weld it, but since you mentioned the tractor parts are hard, that means high carbon content. Funny things happen when you weld high carbon steel, you may be able to reduce the brittleness by TIG welding it to keep the heat down and localized and if you control the cooling by having a partner with a torch slowly drop the temp of the weld affected area.

good luck, tony.

 

[bjowett]

Sweeeeet! Very nice.

Mind if I run a short distance with your idea?... throw in remote actuation similar to the factory diff lock with a little light that lets you know when it is locked/unlocked.

 

[Wrench]

According to Christo Slee disconnecting the sway bar does nothing. You will gain no more articulation with it disconnected. So it is pointless to try.

 

[sleeoffroad]

[quote author=Wrench link=board=2;threadid=17643;start=msg171579#msg171579 date=1086743242]
According to Christo Slee disconnecting the sway bar does nothing. You will gain no more articulation with it disconnected. So it is pointless to try.
[/quote]

Hey, that is not exactly what I said. You will not gain articulation, however in rock crawling the truck is way more stable. The body stays level and the suspension articulate a lot easier.

We have talked about a approach like photoman's for some time, was just not sure we could make it strong enough to take the twist force.

 

[Wrench]

I stand corrected.

 

[Junk]

C'mon Christo, try something like this on the yellow thong. It's not like you wheel your junk anyway