96 LT4: Greetings all, I want to jack up my car and set it down on jack stands where the suspension is at ride height. Where would you all recommend, I position the jack stands to do so?

Also, does anyone else have a rubber diaphragm in the clutch fluid reservoir?

 

I take it you don't want load on the suspension? If load is okay, blocks under wheels or on ramps would make sense. The problem with 'at ride height' is the suspension holding the full weight of the car, any other support other than under the tires would change that. Without load, I've chased before, need to detach the springs (carefully) with car on stands, then use a small jack to raise the suspension to the desired height; not much weight without the tires or the spring.

What's the purpose?

 

Thank you for responding. What I want to do is jack the car up and run it to 75 MPM while on jack stands, but the rear suspension must be a regular ride height so that the angle is the same as when driving. I can do it with the rear wheels hanging there, but the half shaft angles are too wide then.

I want to observe the underneath of the car when its going 75 MPH and see if I can see what the fool things vibtates the way it does.

 

I would think the far easier method would be to strap a GoPro underneath and hit the freeway.

 

Thanks arbee, perhaps your right, however, if one would want to do as I described, do you know where I should put the jack stands?

 

The jack stands should go on each corner of the frame, where the pinch weld wraps around underneath, not far from jacking points. You could remove the wheels so they don't hang as low.
I don't like the sound of your plan though, if it is vibrating that much, I sure wouldn't want to be underneath it! Plus you probably need a load on the tires and suspension to replicate.
Did you check the obvious first, wheel balance, then hubs? It can make it feel like the car will fall apart with a poorly balanced wheel/tire, and usually around 60-70 MPH. I had new tires once, and there was a terrible shake, but had it balance twice, so thought it could not be that. Places were telling me it needed new wheel bearings, a new rack! etc. I took it to a place that had the Hunter road force balancing, and it fixed it.

rubber diaphragm in the clutch fluid reservoir- yes, from the factory. I replaced my MC recently and did not come with one, and will not work with cap, but I think the new cap seals a lot better.

 

That sounds like a good way to end up like that warning label I see on truck chassis.




If you've ever stood next to a car on a dyno, or actually tried to run one near highway speeds on stands you'd have a greater appreciation for the energy and inertia that's going on there.

The GoPro is a good idea, or find someone that knows what they're looking at to inspect the car. Keep your arms and legs attached please.

 

Yes I agree, so where do I put the stands?

 

There is no way you can jack the car off the ground with the rear suspension at normal load. You can put it on a dyno to do it and even thinking to try doing it on jack stands shows no sense>

 

Well, here it is...

 

Better yet, this is far as I can get the geometry correct to run as normal as possible, And oh wow, it was horrible, sounded like the shaft waas coming aapart, seriously eefed. And before anyone asks, the drive shaft has two new u joints and a Sonex slip yoke... effed man just effed

 

Anyone else think of Russian roulette when you saw this?

 

Using jackstands for what you intend is surely tempting ill fate at best. I will never, ever solely rely on jackstands when plan placing my body under any car. I've heard reliable 2nd person reports of people being crushed to death when jackstands gave away. And, even worse yet struggling for life in an intensive care after their spouse or child was able to life the vehicle enough to pull the dead or dying body from underneath the vehicle. I'd rather be overly cautious than foolhardy.

 

Sure looks dangerous to me. How did you determine the suspension was at load height? I'd think it wouldn't give realistic test results since in normal driving the load would vary when actually going down the road.

 

I can only think of one safe way to do this.

1) Put the car on jack-stands on the frame in front of the rear wheels.
2) Remove the bolts between spring and knuckle. This will allow you to lift the wheels to ride height while still all weight is on the jack stands. Measure the treads under the nut before removing to be able to install them in the same height later.
3) Use some straps thru a hole in the batwing web and down to each knuckle to lift and hold the wheels at ride hight. Camber rod joint is probably a good location.

Make sure that the straps can't touch ant moving parts, and secure any loose ends.

 

Greetings all, thank you all for the comments and I certainly agree with everyone who says this was a crazy thing to do and that I’m an idiot. I am, but, as you can see the stands were as close to the center of the tire as possible, but inboard of the tire center line so the angle was not accurately at ride height unless there is a lift in the rear for whatever reason. In this configuration there is no load associated with the drivetrain other than rotating the mass of the wheels and tires. This works well and I was able to measure the speed that the car would go at idle in each gear, given a theoretical situation that supports the circumstances, but that’s irrelevant. Anyway, while accelerating in 6th gear (any other gear would be the same but I’m using 6th because it's the highest) I can induce a horrible vibration and clanking sound, as if several ½’’ nuts where being shaken in an empty paint can on one of those paint can shaking deals. It starts to raise hell at about 60 and smooths out at about 100, then putting it in neutral and shutting the engine off (to guarantee the fly wheel is not an influence) it started to go nuts at about 85 and got worse until about 75 when I thought it was going to leave the earth, then just settled down at about 65 and was sloth as normal. Any thoughts on this? I’m closer to coming up with a unified theory than to solve this problem, Dude.