Measuring ride height

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downsr

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Does some one have a close up photo of where to take the measurements for ride height on 70 Duster. Is it from the lower ball joint to floor and adjusting blade to floor. Then subtract the two. What are they meaning by adjusting blade
 
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Does some one have a close up photo of where to take the measurements for ride height on 70 Duster. Is it from the lower ball joint to floor and adjusting blade to floor. Then subtract the two. What are they meaning by adjusting blade
Adjusting blade raises and lowers the ride height. That description is vague. The measurement is to the blade where it grabs the torsion bar. Directly below the torsion bar where you adjust the ride height.
 
Adjusting blade raises and lowers the ride height. That description is vague. The measurement is to the blade where it grabs the torsion bar. Directly below the torsion bar where you adjust the ride height.
Does some one have a close up photo of where to take the measurements for ride height on 70 Duster. Is it from the lower ball joint to floor and adjusting blade to floor. Then subtract the two. What are they meaning by adjusting blade
From what I recall, the measurement is to the round part of the lower control arm where the torsion bar enters the control arm. They actually have a tool for that measurement that hooked on the grease zerk of the ball joint and lined up with the area I described with a spring loaded scale.
 
Ima thinkin that method would only work with oem T-bars, cuz any other bar might result in a different ride height at the same blade measurement.
I put it into my memory banks years ago that it was the vertical difference between the center of the T-bars and the centers of the LBJs. That works for all bars.
But think about what this spec does; it attempts to put your front end in the center of the camber curve, that minimizes bump steer due to camber changes when the left and right sides of the car are at different ride heights; as in a turn, or bumping over rutted roads. Of course this all goes out the window if your strut-rod bushings are like jello.
 
I am still confused on where to take the measurements. Can not find any good pictures.
 
I have never liked the factory height method. Maybe it is easy on an alignment rack, but a pain on a garage floor. I set height with about an inch between the LCA bumper and frame. Then I measure from the frame to the LCA using the same point on both sides and making them even. This is a little lower than the factory setting. Torsion bar size has no effect on measuring ride height.
 
With some of the above comments to consider. If “all” the suspension pieces are in good working order it is very simple.

Measure from the floor to the adjusting arm at the flattest point on the inner side of the adjuster bolt. This is the A measurement. Measure from the floor to the bottom of the lower ball joint case. This is Measurement B. The measurements should be no more than 1/8th difference. It does not matter what size tire diameter or what size bar is installed! This is the procedure for all cars regardless of tire/wheel size or bar diameter. I find it easier to put some bricks or such on the floor and place my 6’ level across them and confirm level. It is easier to measure down to the top of the level when doing it this way. Course if you have access to an alignment rack all the better. MaPar designed our cars this way to be simple and only one adjustment procedure for all the bodies, engine sizes and bars. They pre-engineered it that way. This will center the upper/lower arms between the stops and set the correct angles in the suspension as well as load the “pre-engineered” bars to the correct value. All this said, it is the procedure for stock Mopar components and the aftermarket may not have engineered this into their products. Further more if you are jamming a 440 in an Slant six equipped A body then use the correct bars and so on.
 
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Thanks for all the info.Hard to get measurement on ball joint to floor because of inside of rim
 
You could run a elastic string between the ball joints and measure from there to the torsion bar.
 
Lacking the tool,
you can remove one front wheel and but a block under the rotor or spindle with the suspension relaxed and the car leveled from side to side. But it is as good as impossible to relax the suspension using this method, as the side with the tire still on may need to be stretched towards the outboard. But you can get a close approximation if you drop the tire pressure to about 10 psi, and re-level the car. The low pressure will allow the sidewall to deflect under the pain of the tire being too far towards the inside. .
Alternatively you can use a wheeled floor jack under the rotor, and jounce the car a time or two, allowing the jack to be the relaxer, as it rolls from outboard to inboard. With the wheel gone, it is also easier to do the measuring.
Just don't let the car roll off the jack with you under it!
 
Here's another version of the picture, with the description for setting the factory ride height and the actual specs. The "V&L" line shows the A-body specs. Like the other picture it shows the measurement being taken at the bottom of the adjusting blade, which is on the round section, not out at the torsion bar adjusting bolt. So the angle of the blade being different for a different sized torsion bar shouldn't matter.

factoryalignspecs.jpg


The other thing is, the factory ride height only provides the best suspension geometry if you use bias-ply tires. If you're using radial tires, the factory ride height specs will NOT give you the best geometry, camber curves, etc.

Just like the static alignment specifications are different for bias ply tires vs. radials, the camber curves, caster changes, etc, are different for radial tires. Think about it. Bias ply tires use specs that are almost opposite for what you want for radials- bias ply alignment specs use positive camber and negative caster. Radials use negative camber and positive caster for the best handling characteristics. The factory ride height takes that into account, it minimizes negative camber gain. Which is what you want for bias ply tires. But it's exactly the opposite of what you want for radials, you WANT negative camber gain on an ideal radial tire camber curve, it will provide the best handling.

Now, you don't have to set your car up for the best handling, that's totally up to you. And most people set their ride height based on the best appearance (in their opinion anyway), not necessarily the best performance or suspension geometry. And that's true at both ends of the ride height spectrum.

But, the idea that using the factory ride height is "best" because that's what the engineers designed for is totally mistaken. The minute you put radials on your car instead of bias ply's the factory design and settings being best goes out the window, because that's not what they were designing for, and not what the factory specs are set for. If you run radials, using the factory specs for alignment and ride height will not give you the best performance.
 
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Where can you get the tool bodyperson
I do not know. Obsolete. Another thing that could work is a straight piece of square tubing cut to the width of your ball joints and notch it for the grease zerks. The best advise comes from 72bluNblu
 
When they refer to adjusting blade are they meaning the bottom of the housing where the torsion bar goes in the lower control arm. Anyone have a pic of the adjusting blade
 
When they refer to adjusting blade are they meaning the bottom of the housing where the torsion bar goes in the lower control arm. Anyone have a pic of the adjusting blade

Across the red line.

28CDE12D-7FAE-41A4-AAF7-4C73B97D3837.jpeg



More specifically right here.

9D981B12-3BF4-4EEC-86A1-39E2444AB562.jpeg
 
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I just measure from the garage floor, to the bottom of the fender. Then match the other side.
Find the height to your taste, and your good.

PS: Before adjusting the torsion bars, loosen the 2 lower control arm nuts a couple turns.
This will stop you from tearing the bushings in the control arms. Tighten them back up after you adjust the height, and the car is on the ground.
 
To each his own.

The fenders would not be my choice as you are not setting it correctly.

If you first set the static height with the nuts loose and need to make minor adjustments down the road there is no need to loosen the pivot nuts again. If you are adjusting inches or more than, by all means loosen the nuts on the pivot first. If it had already been done correctly and that much adjustment is required then one must look for other issues.
 
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If you need more caster/camber help then use the offset upper arm bushings from MOOG to get you there. Adjusting ride height to get this, changes much more to the negative.
 
I just measure from the garage floor, to the bottom of the fender. Then match the other side.
Find the height to your taste, and your good.

PS: Before adjusting the torsion bars, loosen the 2 lower control arm nuts a couple turns.
This will stop you from tearing the bushings in the control arms. Tighten them back up after you adjust the height, and the car is on the ground.

The fenders are not necessarily the same height off the frame, so that's not a real good point to use.

As long as the frame is not sitting on the LCA bumper there is no need to loosen the nut. The LCA rotates around the torsion bar socket.
 
The fenders are not necessarily the same height off the frame, so that's not a real good point to use.

As long as the frame is not sitting on the LCA bumper there is no need to loosen the nut. The LCA rotates around the torsion bar socket.[/QUOTE

Well Jim,
Mopars dont have frames, so thats not a real good point to use either.
Unibody cars, remember ?

Ive studied and worked on these cars for many years. The technique of loosening the 2 lower control arm nuts when making any torsion bar adjustment, is a practice I will continue to use. Im confident in my ability of building some pretty nice cars. Go ahead and get out your levels, calipers, plumb bobs, elastic strings, 2x4s, bricks, land surveyor, and whatever else you think you need. And have at it. :)
 
Pretty sure Jim knows that these Mopars have Unit Body FRAMES. And that the FRAME rails are unitized into the body. And that unit body frames has been shortened to be called Uni-Body or as most people spell it "unibody"
 
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