Bouncing corner-to-corner on compression

[Vertigo]

I've spent over an hour searching the archives and just cannot find anything similar to what my wife's Ty does.

We got the truck in November and since then I've been replacing a lot of the suspension and brake components. So far the idler arm, steering box tightening, ball joints, steering shaft, and poly front control arm bushings have helped out a ton.

I also replaced the stock shocks with the KYB Monomax.
When hitting large bumps on the freeway the truck will compress the suspension unevenly (or so it seems). The drivers front compresses more, bounces off the bump stop, then the passenger rear does the same thing and, depending on the size of the bump, they'll bounce back and forth a couple times. Sure the other corners compress as well, but it feels like two opposite corners stay stiff, while the other two flounder or see-saw.

Why I find this odd is a 1994 Jimmy 4dr 4wd I had 4 years ago did this also.

Alignment has been done
Bushings were tightened with weight on the vehicle
Springs are in good condition (Visually)
No uneven adjustment of torsions noted to get it level on both sides

Two things come to mind:
- Worn rear leaf bushings allowing too much play
- Torsion mount separated
- Do torsions and leafs wear out unevenly?

Am I on the right track?
I plan to get a rear bar for this truck as well but don't feel like throwing money in the wrong direction. I'd rather get this fixed first.

 

[shook0002]

Re: Bouncing corner-to-corner on compression

Mine did pretty close to what your describing, even after new belltechs and bilsteins on it, I put a rear sway bar from 2003 zq8 extreme blazer on it and it helped a lot with body roll and bounce. And it was under 100 bux.

 

[Don W.]

Re: Bouncing corner-to-corner on compression

I can get that kind of bounce when I go over diagonal expansion joints in the fwy. They have to be just right. Only a couple of places locally that cause it and they are bridges that are built on curves. I know that doesn't help but does your issue occur when you hit those fwy bumps "square?" Is it peculiar to certain sections of fwy or all the time? Personally I think it's a combination of our short WB, solid rear axle, and relatively stiff suspension. Also there's a condition called "bump steer" that may be part of the problem. Do a search. Here's one link:

http://www.racerpartswholesale.com/longtech3.htm

 

[dgoodhue]

Re: Bouncing corner-to-corner on compression

I had a problem like this with a Typhoon, replacing the worn out shock fixed the problem (3 of 4 were dead). I later found one of Torison bars was tighten all the way as well, which I guess contributed to the problem.

 

[Vertigo]

Re: Bouncing corner-to-corner on compression

Thanks fellas

Good link on the bump steer problems but that's not exactly what this seems like. It's definitely when I hit larger bumps square on yet anything like expansion joints or railroads that aren't exactly perpendicular get even worse.

I'll bolt on the rear antisway bar in the next couple days as well as order a new bushing kit for the rear leafs. I found the front bushing on the drivers leaf was nearly disintegrated.

Thanks again for the input!

 

[Bichn69]

Re: Bouncing corner-to-corner on compression

I too have this problem.

Have you found the problem yet?

I took my TY in for new shocks and put on the KYB monomax shocks and new ball joints and got it back with this problem. I'm thinking its the shocks.

 

[Vertigo]

Re: Bouncing corner-to-corner on compression

Oh wow. I didn't realize yours actually began when you installed the shocks. Mine was worse *before* the rear shocks.

As I indicated in my PM, I think (even more now) that it's a rear leaf bushing issue.

What's been more on my mind is a chirping prop shaft
:rant:

 

[alwayscode390]

Re: Bouncing corner-to-corner on compression

Mine does it too and I HATE IT. The camaros suspension STOCK is so much better.

It feels like it just bounces from side to side ( but in my head its in a rotational circle ie left driver front then rear, right passenger rear, then right passenger front. It usually bounces 2-3 rotations and freaks me out when I am in the snow because it feels like I am about to spin out) ... when I ask my friends ; they just look at me like WTF?!

I am about to go through an ENTIRE suspension rebuild front to rear , so I probably wont be able to help find the source. I am curious to the answer though ---

 

[dgoodhue]

Re: Bouncing corner-to-corner on compression

Mine does it too and I HATE IT. The camaros suspension STOCK is so much better.

It feels like it just bounces from side to side ( but in my head its in a rotational circle ie left driver front then rear, right passenger rear, then right passenger front. It usually bounces 2-3 rotations and freaks me out when I am in the snow because it feels like I am about to spin out) ... when I ask my friends ; they just look at me like WTF?!

I am about to go through an ENTIRE suspension rebuild front to rear , so I probably wont be able to help find the source. I am curious to the answer though ---

I would try new shocs shock first, as I said it fixed my problem. At the time I also need a full suspension rebuild (160K+ Miles). At 63K miles, If it hasn't been rebuilt before you will find the ball joint will be loose at the very least. You might find some of the sterring componenets worn as well.