Side to side movement with long leafs...

[sled_dog]

Anyone else have this problem? Seems that fairly often my 1997 C2500 sways sideways in the rear end. I'll go around a corner and hit a bump in the middle and it feels like the bed of the truck goes sideways in relation to the axle. I can't say this is actually happening, but thats what it feels like. My only thought is the long(3/4 ton 63") springs are letting the axle move side to side a slight bit and its just magnified up in the bed. Bushings all seem just fine. Thinking I will put in greasable poly ones and see how that goes, and from there, maybe a panhard bar.

 

[sweetk30]

check the rear eyes. common break points. thay made the eye to small and over time the bushings spread in the eye with rust and break them. vary comon in the salt / rust belt.

 

[jarheadk5]

If you're gonna throw parts at it, maybe try an aftermarket swaybar. I've seen them in JCWhitney's catalog for about $150. Certainly won't cure "sway" (as I'm understanding your description of the symptom), but it will help with axle location...

 

[PsychoticDeadGuy]

i have the 63" 1/2 ton springs in mine too. i have 7.5" shackles and i think my axle does the same thing but not very much in my 87' K5. i dont have shocks on it right now and i wonder if that has anything to do with it. i need to replace my tranny mounts so that might be a problem for me. i would say to keep the rubber bushings in it. they flex better, if your is an off road rig, if not then put in some poly bushings and maybe new HD shackles. there a weak point.

 

[jays68yak]

I was talking with a buddy this weekend about front setups and steering. He mentioned either running a stock sway bar or a panhard bar to keep the axle from moving side to side. Our talk was more or less focused on getting the most out of your steering, keep the axle from moving in relation to the frame when steering so that you get the most out of your steering. The more I think about it, it sounds like a good idea. So if everything else checks out, maybe add a panhard bar.

 

[mikey_d05]

I believe quite a few 88-98 (or 92-2000 if you want to be picky) Chevy SUV's are running rear sway bars. Might help axle location and I'm sure you could pick one up for less than $160. Probably worth a shot.

 

[jays68yak]

oh yeah I think I have a stock rear sway bar for a 14bff sitting on the side of my house. $20 if ya want it, but that doesnt inculde shipping.

 

[guido666]

I have a similar problem, but all I have done is 4" rear blocks and 40" Boggers on 15" rims. I was wondering if maybe the change to all that rubber could have just given it more wiggle room. The tires are bias ply and I thought that maybe the truck was swaying back and forth, axle and all, while the tire footprint was standing still. Do you think it could be something like that?

 

[sled_dog]

I truly doubt a sway bar will help. Its not meant at all to locate the axle side to side. Most use links and don't mount directly to the axle/spring assembly like the 73-91 front sway bars do. I've just got to look over the rear suspension well. Pretty certain all the shocks are about done so that could be a contributing factor.

 

[79k20350]

rubber bushing do not flex better because they bond to all surfaces truly tying the 3 parts into one. try to roate a shackle with a rubber bushing, it only goes so far and then bounces back right? thats because the rubber is acting like a spring. as far as a sway bar, that will do nothing for the symptoms hes talking about, hes talking about side to side sway and a sway bar is desigend to reduce body roll onyl, not locate an axle.

 

[sled_dog]

as far as a sway bar, that will do nothing for the symptoms hes talking about, hes talking about side to side sway and a sway bar is desigend to reduce body roll onyl, not locate an axle.

Thank you for backing up my thought process.

I will slightly disagree on the rubber bushings. While polys allow better movement through the straight up and down travel, they don't allow the spring eyes to twist around the bolts. There is give in rubber bushings. I'd say that the twist in the spring eyes with rubber vs the free movement of well greased polys =s out to be about dead even, if not in Polys favor.

I'm considering replacing all bushings with Poly anyway, I'd like to make the truck handle a little better.

 

[mikey_d05]

I haven't looked at any rear sway bar setups up close...I didn't realize that most use links instead of direct attachments

You seem to be pretty good at fab...a panhard wouldn't take that long to rig up. I think it'd be worth a shot if the rest of the suspension checks out.

 

[sled_dog]

about the same thought I was having.

 

[79k20350]

Thank you for backing up my thought process.

I will slightly disagree on the rubber bushings. While polys allow better movement through the straight up and down travel, they don't allow the spring eyes to twist around the bolts. There is give in rubber bushings. I'd say that the twist in the spring eyes with rubber vs the free movement of well greased polys =s out to be about dead even, if not in Polys favor.

I'm considering replacing all bushings with Poly anyway, I'd like to make the truck handle a little better.

The rubber actually grips (kinda glues itself to the spring eye) where as the poly doesnt. Also being firmer the poly doesnt twist like you said. id say a poly bushing is much tighter side to side, thats why they're such a big upgrade in the performance market.

 

[sled_dog]

they are tighter laterally and longitudinally. They are better because they are firmer. The free movement of greased ones is nice too. I think my book at school says "Polyurethane is superior because it holds the alignment specifications we set, better." Thats what it is about, preventing deflection which ruins settings and handling.

 

[jarheadk5]

I truly doubt a sway bar will help. Its not meant at all to locate the axle side to side. Most use links and don't mount directly to the axle/spring assembly like the 73-91 front sway bars do.

That's exactly the way I was referring to mounting it. Directly, like the front one.
I guess, now that I'm thinkling more deeper about it, the fab required to direct-mount a rear swaybar to the axle would probably rival the fab required for a panhard/track bar.
Disregard.

 

[sled_dog]

not a bad thought by any means, I never have liked the front swaybar setup on K5s and such though. I think a swaybar should be just that.