Suspension problem?

[Naio]

This is about my minivan conversion.

When driving, the van feels like it is extremely topheavy and overloaded, but it is not. My gear weighs about the same as the seats I took out, and the heavy stuff is on the floor. Nothing is in the top half of the van except a couple of pillows and hanging clothes. And my head, when driving. The topheavy feeling prevents me from driving at freeway speed.

When parked, windstorms rock the van and I find it necessary to put it up on jackstands. This is inconvenient, as it is supposed to be my daily driver! I asked in another thread about installing jacks, and that is how I came to realise the wind problem may be related to the driving problem.

I have new shocks and tires (LT BFG AT/TA, stiffish shocks, 1000 miles on each). The van is AWD. In general it is in good shape and is not a clunker.

My suspension is of the first type listed on this page:
http://www.carbibles.com/suspension_bible_pg2.html

I see that they say this type does not normally have a lot of lateral stability. Do I need a sway bar? Or is something broken that can be fixed?

Note: I try to avoid posting the make and model of this van, because I have an online stalker who has proven dangerous IRL. For those who know or can guess, please resist the temptation to post the info here. If you really need to know, you can, of course, pm me.

[Naio]

Thank you, j-d!

[j-d]

Yes!

Owners and shops tend to focus on big-ticket items like Springs, Shocks and Ball Joints. They're all important but so are smaller items like Bushings. Your Control Arms have Bushings. Your rear springs have bushings in both ends plus another in the Shackles. They all contribute to ride and handling.

Neighbor brought is Firebird over, saying he had Estimate for $xxx.xx for Ball Joints and did the car need them. We decided that it did NOT, but what it really needed was Lower Control Arm BUSHNGS. Bushing is pressed into Control Arm, OK? There's the outer shell, pressed into the arm, then rubber then inner bushing. Rubber was GONE. Inner Bushing had rubbed through Outer Bushing and cut a track into the ARM. How in H-E-double-hockey-sticks can somebody inspect a front end and render an estimate and not see that? Longer to fix at less profit is my guess...

[Naio]

Alright, today's the day, going down to the shop! Just thought I'd bump this thread first in case anyone has any last minute advice :).

[Salvo]

Apples to oranges comparison. The toad has an extremely low center of gravity. On the other end of the spectrum is the very high center of gravity of a MH. Side to side rocking is exacerbated by a high center of gravity.

Why do you think jeeps and other off road vehicles disconnect their sway bars when rock climbing?

However, you right on with the Koni shocks. I have my adjustable Konis set to max damping.

MEXICOWANDERER wrote:

The toad has independent rear suspension. The rear sway bar has done ZERO to degrade the handling of the car hitting deep Mexican grade one wheel potholes. With a solid axle and leaf spring rear end the non-effect of torsional flex applied to the other side is even less if that means anything.

[Naio]

j-d wrote:
The broken sway bars I've seen, have incorporated tubing and various welds to form what looks at first glance like a solid bar. I have not seen a broken solid bar.

These vans, some had tubular and some solid. From the cracks, I would say mine is tubular.

My guess is that the cracks mean that your bar is not acting as a torsion spring any more. In other words, not doing what it was designed to do. That something is prevent a rolling movement by transferring weight to the side that would sway up.

Ah. Good point.

I did the add-a-leaf fix on our first Class C. It stopped the swaying and bottoming the coach had when we bought it. It did, however, raise the rear above level relative to the front. I'm pretty sure our front springs were sagged too, just never changed them. I'd suspect your fronts, as well as rears, are tired out.
My opinion, and I say it realizing others may disagree, adding a gizmo like air shocks, shocks with coil springs over them, booster springs, coil spring spacers, etc etc aren't long term solutions. A failed spring needs a new spring.

Yeah. I do have new coil-over shocks on the van. Because I thought they were the problem :/.

[j-d]

The broken sway bars I've seen, have incorporated tubing and various welds to form what looks at first glance like a solid bar. I have not seen a broken solid bar. My guess is that the cracks mean that your bar is not acting as a torsion spring any more. In other words, not doing what it was designed to do. That something is prevent a rolling movement by transferring weight to the side that would sway up.
I did the add-a-leaf fix on our first Class C. It stopped the swaying and bottoming the coach had when we bought it. It did, however, raise the rear above level relative to the front. I'm pretty sure our front springs were sagged too, just never changed them. I'd suspect your fronts, as well as rears, are tired out.
My opinion, and I say it realizing others may disagree, adding a gizmo like air shocks, shocks with coil springs over them, booster springs, coil spring spacers, etc etc aren't long term solutions. A failed spring needs a new spring.

[Naio]

Alright folks, I am here to report on further findings.

The front sway bar has multiple cracks but has not actually come apart like some I have seen online. The cracks don't go all the way around. Am I right to think I need to replace it soon-ish, but it is not the cause of my problems?

The rear leaf springs are flat. This is something I saw a couple days ago, but did not process until lying in bed last night. 'Wait a minute... aren't they supposed to arc?' Yeah, they are.

The leaf springs are generally agreed (in van forums) to be too wimpy even when new. There are heavy duty and add-a-aleaf options, but they have various drawbacks (add too much lift, don't fit existing brackets, etc.). I will look into smkettner's alternative thingy more.

Questions:

- Are the leaf springs the reason the van sways in the wind (parked) and corners terribly (driving)? Or do I need a rear sway bar ALSO?

- Is the front sway bar ok until I get home (100 miles, 2 months)?

Thank you all so much!

[MEXICOWANDERER]

Normal with vehicles with bad or insufficient shock absorbers. I nicknamed the effect "Hobby Horsing". Despite their horrendous cost I started using KONI shock absorbers along with the largest sway bars I could fit front & rear. As I have aged my driving skills have deteriorated markedly. Improvements in control and handling to me are borne of necessity to keep out of accidents and stay alive. The Koni shocks I fitted to the toad have gone eighty-thousand miles without needing to be adjusted stiffer setting. I have this peculiar fettish about safety being worth the money. One tiny accident would cost more than ten sets of Konis and sway bars.

The toad has independent rear suspension. The rear sway bar has done ZERO to degrade the handling of the car hitting deep Mexican grade one wheel potholes. With a solid axle and leaf spring rear end the non-effect of torsional flex applied to the other side is even less if that means anything. 50-years ago when I was auto-crossing in the Tiger sway bars became detrimental in a G-force 180 when it would lift the opposite side tire off the ground. If I tried a stunt like that in the toad I would slide off the road in a skid. The sticky 4.50 10
50 13" Goodyear Blue Streaks created the sway bar tire lift phenomenon.

[Naio]

Salvo, I've added those questions to the list of what to test out tomorrow :).

Anybody else have suggestions for what to investigate?

Thanks, smkettner, for the springs alternative.

I have been reading, reading, reading on the van forums, and taking copious notes. A few days ago I knew nothing about suspensions, but now I have half a clue.

I will go back under the van in a bit and look with smarter eyes. It has become clear that I could easily spend $1000 on suspension upgrades. I think I will need you folks' help prioritizing.

[Salvo]

What happens when you go over a speed bump at an angle (about 45 degrees to the bump) at slow speed? Does the chassis really start to rock side to side? That's a sign of inadequate shock damping. If you install a rear sway bar, under these conditions, rocking will get worse!

How does the van react when a truck passes you on the freeway? Do you get an excessive side push or just a slight push? I have to compensate with steering somewhat, but it's not a white knuckle situation. If it's excessive, then you can use a rear sway bar, otherwise that's not your problem. BTW, if your tire sidewalls aren't strong enough you'll get a similar excessive side push.

Naio wrote:

He reminded me of something I had forgotten to tell y'all, which is the van's tendency to set up an oscillation after it goes over a bump or a dip. It feels like the road goes up and down and up and down... but really it was just one bump and the van doing the rest on its own. This is with new, stiff shocks. It's especially bad if the bump is hit while cornering.

[Naio]

No, I don't have any water tanks (good question!).

Air shocks are available for my van. I just got new shocks, of a kind other folks with my van say are on the very stiff side, but they are not air adjustable.

[DrewE]

I've heard pretty good reports (on other sorts of smallish vehicles, at least) for monroe air shock systems. You might want to see if they exist for your minivan. The advantage there is that you can adjust the air pressure in the shock to suit the load on the vehicle; it adds some force to the springs.

If you do get air shocks, make sure you get a kit with separate lines and valves for each side. Some of the kits come with a single line for both shocks and a tee for the fill valve (which is just a tire valve). With that setup, the air can flow between the two sides and make the vehicle less stable in lateral rocking, which of course is what you're trying to avoid.

Another thought: do you have any water tanks in your conversion? Is it possible that water is sloshing around and throwing the balance off while doing so?

[Naio]

Hmm.. you folks have given me good things to google!

Turns out, my van comes stock with front sway bars (but not rear) and they are famous for breaking. Tomorrow, I will attempt to locate mine and take a look. Also they have some bushings that come in an improved after-market version (as do the bars). Maybe something IS broken.

I have an appointment with my friend to get the van off its jackstands, go to a scale, try out some different tire pressures, and then go to the suspension shop, all on Weds. I am trying to learn and investigate everything I can before that, since taking it off the jacks is a bother.

[time2roll]

+1 for a rear sway bar.

Consider roadmaster active suspension for rear leaf springs.
http://www.activesuspension.com/

Have the suspension inspected by an alignment specialist.