Tuesday, May 17, 2011

How to disconnect the front sway bar?

Since the lift I'll be going with doesn't have a good swaybar option, I'm going to start to focus on how to put a swaybar on it. Here's some details on the disconnect mechanisms available, and why we need it.

In fast offroad sweepers, or when coming into a corner on the brakes, the rear of the 4Runner wants to come out and has to be caught. Last weekend, in a sand wash doing about 30-40, we spent a lot of time sideways - much more than was intended or preferred!

Its on-road manners are similar, and oversteer is the least desirable trait for onroad driving. Car manufacturers generally dial in understeer when they deliver their vehicles; it's the safest of the available choices.

From the details below, you'll see this means the front is too soft. So we'll need stiffer springs or swaybar. And that means less flex. Which means we need to be able to disconnect it.

Ok, so we know we want to disconnect the front sway bar. How does one do that on a Toyota?
This gentleman put together a very comprehensive list of swaybar disconnect options, and also walks us through his DIY efforts. Unfortunately,  like so many other great pages which have been around a while, links to other sites/pages are broken. So I'm going to use a common practice and copy some of his content here in case his page goes away.

At one point, his prototype broke, leading to this comment:
"Originally I constructed these disconnects out of 3/8" hardware. After crossing up the vehicle off road with the disconnects I was able to snap one side. For the street the 3/8" hardware was strong enough but if you wheel with the disconnects installed they will break. Hence, I built bigger ones shown above. You can also see the difference in hardware size from the other picture below. "

Can you imagine what would happen if you were in a fast sweeper and the front sway bar link broke? Front swaybars keep the rear from coming out. I borrowed the bullets below from the Ozark Porsche Club's suspension document
  1. To induce oversteer because your car won't turn in quickly enough:
    1. Stiffen the rear of the car with bigger springs, shocks, anti-sway bar, or some combination of these or. . . .
    2. Soften the front of the car with smaller springs, shocks, anti-sway bar, or some combination of these
  2. To induce understeer because your car is "tail happy", reverse the above:
    1. Stiffen the front of the car with bigger springs, shocks, anti-sway bar, or some combination of these or. . .
    2. Soften the rear of the car with smaller springs, shocks, anti-sway bar, or some combination of these
Breaking a swaybar link offroad flexing across a rut means it was NOT OK for the street, it was in fact dangerous, risking an accident.

Ok, so we want a strong and safe part. :) Some of the other things to consider:
  1. Disconnects work by making part of the link that connects the swaybar end to the truck or suspension part removable. This often requires that you have a zip tie handy to tie your swaybar up. Somehow, much of the market is OK with these solutions. The product I used on the Blazer included a frame mount where you just reused a pin to lock the swaybar to the frame while you wheeled. No zip ties.
  2. Gosh, wouldn't it be nice if I could do this with a button in the cab?
    1. This fellow has done it, but has provided very little detail on the parts he used. After a surprising amount of searching, this looks to be a device found on a Nissan Patrol GQ or Y61. MSRP appears to be in the $1,000-3,000 range depending on the unit.

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