My rear suspension is off. The drivers rear is 1" higher than the passenger. I'm measuring from the center of the hub to the fender lip. I was thinking of trying an after market shackle on the passenger side to lift it to the same height as the drivers side. Any thoughts, might this be dangerous on the highway? Thanks in advance.
different size shackles?
- Thread starter latamud
- Start date
Is the frame bent at all? If the frame is straight, then your springs are worn out.New ones are not all that expensive, and should cure your problem. Also, it sounds like the passenger side is more worn out, and that's the side that has to control the spring wind up the most( to prevent wheel hop). So getting fresh springs will also help you accelerate faster, as well as handle better.
They are new springs. I replaced the old ones because of the difference in ride height. It is possible the frame is bent but I see no signs of an accident under the hood nor in the rear. I'm just wondering if I add a longer shackle on one side if its going to mess up the dynamics of the suspension? Or, maybe correct it?
Measure from a known point on the chassis to the ground. Hub to a body part isn't a very accurate way as both of those components can shift around quite a bit. The ground doesn't move, usually. Try the control arm bolts in front, and the rear spring mounts as a place to hang a plumb from. What about the distance between the ground and your rear bumper? Is it even from one side to the other?
But if your ground is crooked, well.. I don't know. If your car isn't at a driveable stage at the moment, then it's the wrong time to be asking about these things. Your springs may still need to settle.
But if your ground is crooked, well.. I don't know. If your car isn't at a driveable stage at the moment, then it's the wrong time to be asking about these things. Your springs may still need to settle.
ron67fb said:
Measuring from the fender lip to the center of the hub is constant. The distance will stay the same no matter the slope of the ground, nor the slightest difference in tire pressures. That distance only measures the height the suspension holds the car up to. If the car is jacked up at the control arms and the wheels removed the distance from fender lip to hub center is still the same. Bumper brackets can be off side to side and give an inacurate measurment. The question is, if I put a lifter shackle on one side and keep a stock shackle on the other, will the suspension dynamics be affected negatively?
Suspension dynamics
I'm not sure how this will affect handling, except if you have any bump steer it will become asymetrical.
From your comments I don't quite understand where the dimension difference is coming from.
I reccomend checking the vertical frame alignment.
Here is a copy of the factory alignment drawing.
I notice the dimension at the rear spring front hanger is a little blurry, it is 8.14".
If you have any difficulty reading any other dimensions, let me know.
Roy.
I believe the suspension dynamics will be slightly skewed.latamud said:
I'm not sure how this will affect handling, except if you have any bump steer it will become asymetrical.
From your comments I don't quite understand where the dimension difference is coming from.
I reccomend checking the vertical frame alignment.
Here is a copy of the factory alignment drawing.
I notice the dimension at the rear spring front hanger is a little blurry, it is 8.14".
If you have any difficulty reading any other dimensions, let me know.
Roy.
Short of working on your chassis bolted onto a jig, your ground must be level before measuring anything related to ride height. See, there's this thing called "gravity" that likes to make sprung masses tilt towards it.
So we'd rather check ride height first before making sure all your tire pressures are equal?
If you jack it up at the spindles/rotors (front) or axle flanges/drums (rear), then cycle the front control arms to make sure the track is the same as ride height (which needs jackstands that can freely move left/right), then yes, but who does that?
Correct. So you measure from the bumper to the trunk to make sure the bumper itself is straight. Oh, the body might be crooked? Guess what, your fender lip is part of the body, so we're back where we started.
My point is to take many measurements just to make sure. When I said from chassis to ground, I meant with all four tires sitting on the ground after the car has been rolled into position, not jacked up.
Try measuring from the rocker panel to the ground, as the rocker panel is one of the main structural members and is not usually hit during an accident. Different readings around your rocker panel may show if your frame is twisted. For example, if you show LF 4", RF 4", LR 5", RR 4" then that tells you the floor may be warped up on the left rear.
So let's say you add a 1" lift shackle to the RR, what did you fix exactly? Nothing. You've preloaded the RR, which effectively preloads the LF to some extent. Now your LF will end up lower than your RF.
No tires installed yet? If not, again, this is the wrong time to try and estimate your final ride height. You still didn't mention if you've driven on these new springs or not to settle them.
In the event that you're still looking for a half-baked "fix", Id suggest getting air shocks and plumb the left/right shocks separately and inflate until "even". At least nobody will laugh at you when they see different length shackles poking under your rear panel.
MitchGT said:
Yes, the shocks were replaced at the same time. The shackles are pointing at the same angle. The stock shackes I'm using have shoulder bolts so there is a stop that lets me know not to overtighten. After I set the car back down I loosened the shackles and the front leaf bolt enough to let it settle, drove around the shop and tightened it back up so I'd have my ride height.
RGR on the "gravity". I am not working on a perfectly flat surface. Also, I do not have a perfect surface to work on. The ground is level enough for me to see that one side is higher than the other, conversly the front has the same problem.ron67fb said:
The tire pressure is not relevant in my measuring if measuring from the hub center to the fender lip. That distance doesn't change at rest. Therefore I don't need to equalize the tire pressures, so it is a more accurate measurement than measuring from the ground to the fender lip. At rest, on a relatively level surface these measurements will be constant and comparable to eachother.ron67fb said:
The weight of the car will bring the suspension to its resting height. On jacks(not individually leveled) and measuring from the hub center to the fendser lip you will still get our constant measurement. I was generalizing, my jacks have wheels on them and I should have been specific on that, but I never said to put the car on stationary jackstands. It will be the resting point of the front coil holding the weight of the car on top of it. When you get an alignment, they do this. The alignment conputer aligns the wheels comparable to the ground not the car. You can still get a good alignment with a car's suspension unequal and the computer doesn't care how the car is sitting.ron67fb said:
True, but bumper brackets can be mounted unleveled. If you push a bumper up on one side and down on the other and then tighten up the frame bolts the bumper will be higher off the ground than the other side. The bumper can still be straight but not true to the car. In this case the rearmost point of the front bumper will still measure the same to the trunk. Yet, measuring the height on one side and the other there can be a difference. Imagine a car that measures 15" high on one side but 14" on the other. Yet, when mounting the front bumper we level it to the ground. Can you see the bumper sagging on the high side?ron67fb said:
My point is that the measurements I'm making make measuring elsewhere unnecessary.ron67fb said:
ron67fb said:
But, lets say the LF started out higher than the RF then we'd fixron67fb said:
NOT nothing.
I've been driving the car, all tires are the same size, purchased and mounted at the same time. I'm not trying to estimate height. Getting back to the original question for the second time, will doing this affect the dynamics of the suspension negatively?ron67fb said:
Ever think of a shorter shackle on the other side? Using air shocks would do the same thing but cost more than some scraps of steel and bolts. I'm working with 1" difference, not 5".ron67fb said:
Thanks for all the help everyone. I'm just going to remove a leaf from one side. Then I'm going to run a stock coil up front on one side and a 620 on the other. Or, I can put some dumbells on the higher side to weigh it down. No, even better, HYDRAULICS!!!!!
ozstang65
Founding Member
How does the front end check out? One side out here can effect the rear also. Might be a front and not a rear problem?
Platonic Solid
Founding Member
You’re looking for a solution to a problem that hasn’t been properly diagnosed, thus your original question isn’t answerable with any accuracy.latamud said:
I would be concerned about driving this vehicle in either state (with or without mismatched shackles.)
.
Fender clearance.
OK.
From all you've explained I think I understand what you want.
I definitly would NOT! remove a leaf or modify my front to compensate.
I understand you just want a simple solution but I agree with
Some of the guys earlier talked about the problems measuring.
This is what I would do:
Jack the car of at 4 points.
Shim the blocks or jacks or whatever so that the platform is level.
The diag I posted has the exact dimensions from a points on the chassis to a plane.
Measure the distances listed in the diag.
If the frame is not bent, ie. the subframes are positioned correctly, the problem must be in body alignment.
You say you haven't found evidence of a hit, but it sounds like the quarter panel might have been replace and not set up correctly. Thats just a wild a$$ guess.
You wont know until you make the measurements.
Roy.
latamud said:
OK.
From all you've explained I think I understand what you want.
I definitly would NOT! remove a leaf or modify my front to compensate.
I understand you just want a simple solution but I agree with
Platonic Solid said:
Some of the guys earlier talked about the problems measuring.
This is what I would do:
Jack the car of at 4 points.
Shim the blocks or jacks or whatever so that the platform is level.
The diag I posted has the exact dimensions from a points on the chassis to a plane.
Measure the distances listed in the diag.
You say you haven't found evidence of a hit, but it sounds like the quarter panel might have been replace and not set up correctly. Thats just a wild a$$ guess.
You wont know until you make the measurements.
Roy.
HAHA, sorry for the hastle and thanks for all of the input. I pulled all the junk out of the car from body work and whatnot. The car must have been weighed down on one side more than the other because it sits level when empty. Coincidentally I did rebuild the rear leafs, added 2 on a negative arch to lower the rear, got 3" out of the mod. Good thing too, to centering peg that was on the lowering block broke and the rear end shifted a bit. So, now the rear is level, stiffer(7leafs), and lowered without blocks.
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