Rear trackbar thoughts

[Trango]

Hi Folks,

I continue to battle steering uncertainty at speed. After much thought and under-carriage staring, I am thinking that the ability of the rear suspension to "Swerve" on its on is a major contributor.

I've already shimmed the "windows" or "pockets" that the rear leafs ride in, and that has tightened things up a fair bit by eliminating independant wandering by either of the axles (now, since they are much more tied-together laterally, they must swerve as a group). However, they are still swerving quite a bit.

So, how to automakers cure lateral swerve in leaf-sprung vehicles? They add a trackbar. I am thinking of doing this, and probable will do this in the rear of the rear tandem. I would most likely use and modify an extra control arm mount I have lying around, with maybe some extra lateral reinforcement on the axle. That way, I don't have any welding to the axle and if it doesn't work, I can easily remove it.

There is a space to do this from the pass side frame to the driver's side axle. In building suspensions, you want the trackbar as long and as flat as you can make it, OR you want it as much in sync with the existing suspension, whichever is more pertinent. I am thinking that horizontality is important, as is length, with an eye towards the fore and aft movement of the suspension (as dictated by the bogie arms already on the vehicle).

Has anyone ever thought of this, or performed this before? All thoughts welcome!!!

Best,
Bob

 

[BFR]

I like the idea, but am concerned you might be providing a pivot by putting the trackbar on one axle. This might change the wallowing around when you hit a bump at speed into a violent jerk when you hit a bump at speed.

 

[m-35tom]

that is called a 'panhard rod' but you are trying to fix something that should not be a problem to begin with. i ran mine at 70 many times as it was on the interstate more than anywhere else and it handled very well. you have some other problem. i am sure you have checked the alignment, but it needs at least 1/8" toe in to track properly. i also assume you have balanced all tires as out of balance may unload the rear enough to lose its grip on the road.

 

[rizzo]

could it be loose where the rear springs pivot? in the bogie?

 

[rizzo]

My 543 does 70 with no problem on 16.00 r20's

 

[Recovry4x4]

I would also be concerned about closing up the windows in thespring pads. Statically makes sense but you need that space if you ever get it off camber or doing the RTI.

 

[ken]

I would be conserned the boogie bearings are bad. The pivot where the leaf springs mount to the cross bar. I have seen some trucks with timkin roller bearings and others with brass bushings. Pull the covers off and check them. I believe the Lube Order wants them greased quite often. This has been overlooked on most of the dueces at the fire station. Most of them were dry when we got the trucks. Make sure that you loosen the covers when adding grease. There should be a zerk fitting on the bottom of the carrier. If you don't loosen the cover the grease will blow out the inner seal as you add the grease. I've also had the front ubolts being loose cause a wandering problem on my truck. I ended up getting new ubolts made because they streached too far and wouldn't tighen up anymore.

 

[Trango]

You know guys, I've wondered just how tight those bogie bearings should be, since that's where all the "slop" is. In any event, that's a heck of alot easier than building a trackbar, so I'll check on those bearings, and report back.

Part of the issue, by the way, is semi ruts, and the fact I'm singled out. But, so are a few of you, so it sounds like my setup isn't terribly unique.

Anyway, I'll start with the bogie bearings. Thanks for the feedback!!!

 

[Trango]

Oh yeah, front U-bolts are tight, but thanks for the idea!

 

[spicergear]

I've driven a deuce with the bed of and watched the rear suspension dance around, but does it actually 'swerve?' With the two lower links it should move side to side some but dead even.

 

[m-35tom]

the bogie brngs should have no play at all, probably a slight preload.