Imperial Home Page -> Repair -> Suspension -> Ride Height
Tip from Ross:
The factory manual has the correct procedure per year model. Keep in mind that the usual load ought to be in the trunk, a full tank of fuel on board and level ground to perform measurements is necessary. I also place 200 lbs of weight on the drivers seat and floorboard to approximate the driver's presence AS THIS WILL MAKE A NOTICEABLE DIFFERENCE. Additional measurements may be made at the rear of the front wheel-wells and at the front of the rear rear wheels to determine other, related issues: improperly repaired damage, (unibody torqued), unequal rear spring sag/worn shocks (not unusual for passenger side to go first, it takes most of the torque load on acceleration especially on non Sure Grip cars), unequal trunk weight distribution. Level adjustments might need to be made more than once: Tire pressure checked again (overnight, cold: at recommended pressure, or, at the best compromise from the "24 psi bias ply" tire days which for me is 32 psi all around: be certain to maintain the front/rear pressure differential. On mine, the recommended pressure is the same front/rear) as it has the ability to most easily affect perceived change. Also, a good penetrant on the adjustors works wonders: "Kroil" by Kano, or my favorite, "SP-100" by Prolong (NAPA)
Tip from David:
I just found out when taking the height measurements the following factors must be taken into account: the car must have a full tank of gas, the top must be all the way up, and the front seats all the way back. According to my source this was the only way to get correct measurements. I know this sounds a little anal, but obviously there are factors that must be taken into account if you want to achieve the correct off the assembly line height for your car.
How to measure ride height:
In section 2 of the '66 FSM for the front suspension, it states that ride height is the first measurement to set for any front suspension adjustment. It's measured as the difference between "lowest point of one of the lower control arm bushing housings to floor" and "from lowest point of flat portion on bottom of lower ball joint on same side." There's an illustration showing "A" & "B" points on the car. For Imperials, this measurement in inches is 2 plus/minus 1/8 for "Standard Suspension" and 2 3/8 plus/minus 1/8 for "Heavy Duty Suspension" or "Limousine Suspension". The max side to side difference is 1/8 inch. This '66 FSM gives a measurement of 1 1/8", +/- 1/8" for the Chrysler, which may not be the same for the '64. These measurements are only done on chassis points, not on the body, so I think this confirms Norm's point that variables probably prevent the FSM from giving accurate specs on ride height when measured to any body points. However, I've taken a tape measure to my '66 a few times, trying to compare wheel wheel heights, from & rear, on my car. That's what I did with Dave Doty's car near mine on Sunday. But you're probably just as well off eye-balling your car from a distance.
Measure from the ball joint to the floor, measure from the torsion bar anchor housing to the floor, subtract first measurement from second, the value should be 2" +or- 1/8". The height should not vary more than 1/8" side to side. Adjust by cranking on the torsion bar adjusters (up or down). Just make sure you have a LOOOOONG breaker bar as the adjustment bolts are a pain to turn.
The torsion bars ARE adjustable for ride height, and since we all know (right?... well we do now) that changing height (front or rear) affects steering geometry and thrust angle (as well as drive shaft alignment) the first step in any front end alignment with adjustable height should be to check for correct height. This may be a lost art at a lot of suspension shops, but you can check and adjust as follows: 1. Bounce the car several times and let it come to rest. 2. Measure from the lower ball joint rim (not the grease fitting) to the floor (you need a level smooth spot to do this). Now measure between the floor and the point where the torsion bar anchors to the lower control arm (not the nut on the end of the bar, but the clamp inside the control arm. The arm is shaped like an upside-down "U" and this clamp is inside the "U".) It is important to measure at the correct points to obtain the correct measurement. 3. The torsion bar should be 2" +/- 1/8" higher than the bottom of the lower ball joint for '62 & 63 Imperial. 4. To adjust, you will need either a 1 1/8 or 1 1/4" six point socket and a BIG breaker bar or ratchet. The adjuster bolt is at the tail end of the torsion bar where it anchors to the cross member. Having the ride height misadjusted will most drastically affect your camber, which will cause high speed shimmy and/or wandering (the lack of feeling "centered" in straight and level flight). Get it set right (or take this with you and show it to the alignment man and tell him you want the ride height checked and set BEFORE he does the alignment). If your shop argues or won't do it that way for you then find an- other shop. We spend too much time and money on our beloved machines to not do things properly...especially something as easy, yet critically important as front end alignment. In NY, F.E. alignment is a safety inspection item, so yes it IS important!
The correct method of measurement has no bearing on appearance. The Factory suggests measuring from the bottom of the lower ball joint to the ground, then from the bottom of the outside diameter of the lower control arm bushing to the ground on each side , one at a time. On each side the difference between the two measurements should usually be 2 inches, give or take an eighth of an inch. In other words, the distance to the ground on one side in both cases should be compared, then the other side the same thing. Also remember to bounce the car before making the measurement. Additional reasons for high speed stability problems include weak or Over arched rear springs and poor strut bar bushings in front . Incorrect tires and or tire pressure will contribute to the phenomenon. Poor alignment will most certainly contribute. Remember, everything in the way of looseness is magnified as a consequence of speed.
Question from Mike (1967):
I felt my Imperial was sitting a bit low in the front, so I looked in the FSM, it gives dimensions for height adjustments. I turned the passenger side torsion bar adjusting bolt a couple of turns (it has about 1/2+ of it's adjustment left) then went to the drivers side , found the adjustment bolt turned all the way in-no adjustment left. ( the rubber rebounds on that side are completely smashed to pieces, like it's been bouncing on it for a while) I figured that like old leaf springs, that right side bar has got old and tired and needs to be replaced. I got the Mopar part #'s and went on parts voice found some bars, ended up talking to Mr. Mitchell , he said he would like to sell me some bars, but it wouldn't solve the problem, he said torsion bars don't wear out , he said something else is probably broken. My question is, is it "normal" or right for the drivers side bar to be adjusted all the way and the pass. side bar bolt only 1/3 to 1/2 ? , do I have a problem here, if so could it be a cracked weld, bad bushing or a broken/extremely worn part ? any advice on removing a torsion bar or is this a job best left to a suspension shop.
A very likely scenario is that either the adjusting bolt or the threaded nut that it interacts with is stripped. The torsion bar is tensioned or released as a result of the bolt's action on the nut, which moves the bar in one direction for more tension, the other for less. Corrosion or mechanical stripping or the bolt and/or nut could be culprits.
Also check the rear mounting bracket. Be sure the bar is being held in the correct position there.
I went through all this on my '65. I was convinced I needed a new torsion bar, so I got a pair from a '66 in a salvage yard, along with the mounts and adjusting bolts. Took the whole lot to the suspension shop. They installed a new lower control arm bushing, and replaced my old (stripped) adjusting bolt and put the new torsion bars back in the trunk.
Problem solved! Moral of the story: check the adjuster and the bushing.
I just read my September issue of High Performance Mopar and they have a story about torsion bars in this issue. They said that there is a left and a right side for these bars and if you get them mixed up you wont get the car to set right.
Follow-up from Doug:
Torsion bars only twist one way. So naturally left and right torsion bars differ from one another. You must label them when removed as to not install them on the wrong side. A wrongly installed torsion bar is downright dangerous. Not only does the car not sit right, but the torsion bar will eventually snap because the weight of the vehicle is forcing it to twist the wrong way (especially when cornering). That said, torsion bars are a great suspension system easily outlasting a conventional coil spring.
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