Adjusting Your Classic Mopar’s Ride with the Torsion Bars
Most of our classic hot rods are built with front ends that are supported by coil springs. However, our A-, B, and E-body classic Mopar rods built with torsion bar front suspensions. With coil spring suspensions, ride height and stiffness are controlled by the coil springs we install. With torsion bar suspensions, these are controlled by the torsion bar. In this article we’re going to discuss what torsion bars are and how they control ride height and stiffness. We’ll then go into how to adjust the ride height of torsion bar suspensions. Finally, we’ll talk about how to replace them to get a stiffer ride.
What Are Torsion Bars?
Basically, a torsion bar is a high-strength steel bar that connects to the frame behind the front wheels and the lower control arm. Both ends of the torsion bar are hexagonal-like a nut. The socket the ends of the torsion bar fits into is also hexagonal. The socket on the frame behind the wheel is fixed-it can’t move. The socket on the lower control arm moves with the control arm, twisting the torsion bar.
How Do Torsion Bars Work?
The torsion bar twists as the lower control goes up and down, resisting the up and down movement of the frame and suspension in relation to each other. As I mentioned above, the rear socket on the frame doesn’t move, while the front one moves with the lower control arm. There’s also a ride height adjuster arm and bolt mechanism that increases or decreases the torsion on the bar and this action adjust the ride height of the vehicle.
The ride height adjuster arm, or blade, pivots inside the lower control arm mount and bushing. When you turn the ride height adjusting screw, this blade pivots at the bushing, turning the hex socket where the end of the torsion bar resides, adding or removing torsion on the bar. If you add torsion to it, you adjust the ride height up, whereas removing torsion (or tension) from the bar lowers the ride height. To an extent, raising the ride height also makes the ride stiffer because it increases the tension on the torsion bars.
Adjusting Ride Height with the Torsion Bar
The easiest way to do this is to raise the front end of the car using a jack on the k-frame and then using jack stands to support it. Park the car on a flat and level surface and block the rear wheels after ensuring that the transmission is either in gear or Park and the parking brake is firmly set.
Slide a piece of cardboard under the car, or use a creeper. Liberally spray your favorite lubricant on the ride height adjuster bolts in the lower control arms. On some cars, it may also be helpful to put a socket over the head of the bolts and tap the socket a few times with a hammer to loosen any rust.
Remember-righty, tighty-lefty,loosey. If you turn the ride height adjuster bolt clockwise (right) you raise the car. Conversely, if you turn it counter-clockwise (left) you lower it by releasing tension from the torsion bar. Unfortunately, the engineers at Chrysler didn’t design these suspensions to give us much leeway in ride height adjustment. Using the torsion bar to adjust ride height is just to fine tune the ride height-maybe a couple inches at most. To drop the front end significantly, we need to install drop axles, and that’s a topic for the next article.
The Problem with Stock Torsion Bar Suspensions
I’ve owned two cars with torsion bar suspensions. Both were Chargers- a ’74 and a pre-production ’65. Until I swapped out the torsion bars, both drove like tuna boats. Great if you want to imagine that you’re on the high seas, but horrible if you’re trying to carve a corner, or even get a good 60-foot time at the track. I replaced the torsion bars with 1.03-inch diameter bars pretty quickly. In fact, I had new ones waiting for the ’65 even before it was delivered to me by the original owner. Swapping them out isn’t terribly difficult, it’s just time-consuming. Let’s see how to do this.
Step 1: Get the Front End in the Air
As always when working on the suspension, park the car on a flat and level surface. This means your angled driveway is out of the question. Put the transmission in gear or Park and firmly set the parking brake. Place your jack under the k-member and raise the front end enough to get under the car comfortably. Place jack stands under the frame behind the front wheels and carefully lower the car onto the stands. If you’ve got ramps, use them. Put your Sam Safety Glasses on now. DO NOT SUPPORT THE CAR BY THE LOWER CONTROL ARMS OR BALL JOINTS!
Step 2: Remove the Tension from the Torsion Bar
Slide under the car so you can see the bottom of the lower control arm. Inside the lower control arm, you’ll see a bolt about two to three inches outboard of the lower control arm pivot point. This is the ride height adjuster bolt. Using a 5/8-inch socket (Maybe a 9/16 on some cars) loosen this bolt until it flops around loosely. You want every bit of tension off the bolt and thus off the torsion bar.
Step 3: Remove the Torsion Bar Retaining Clip
Move to where you can see the rear of the torsion bar socket in the frame behind the front wheels. Using a pair of pliers, carefully remove the torsion bar retaining clip. It’s like a C-clip with wings that wrap over the upper lip of the torsion bar socket. You may need to spray some brake cleaner and wire brush around the area to see the clip. Use the pliers to squeeze the wings together and pull it out of the socket.
Step 4: Clean the Torsion Bar
Wait. Clean the torsion bar that I’m going to remove? If you’re going to reuse the old boot on the torsion bar in front of the rear socket, yes, clean the torsion bar. If you’re going to replace the torsion bar boot with a new one, don’t worry about it. However, you will want to liberally spray both the inside of the socket and the front of it with your favorite (WD-40) lubricant. Smack the socket on both sides of the frame a few times, just hard enough to let it know you’re there but not hard enough to leave marks. You just want to dislodge any rust and loosen the grease up some.
Step 5: Remove the Old Torsion Bar
If you want to be like a suspension professional, you can look around and get yourself the correct Mopar Torsion Bar tool. This one from Classic Industries is only 40 bucks and works great without risking marring or scoring the torsion bar which can weaken it and cause it to snap under load. If not, and since we’re junking the old ones anyways, just use a good-sized pair of Vise Grips and clamp them tightly.
Now, give the torsion bar sockets, front and rear, a liberal spray with the lubricant/liquid wrench again. Wiggle the torsion bar clamp/Vise Grips back and forth as you smack your clamp towards the rear of the car. You should only need the bar to move about an inch before it’s free. Your hammer should be hitting your clamping device as close to the torsion bar as you can get it. If you don’t, you’ll be dissipating the force of the hammer into the tool and your hand instead of using it to release the torsion bar. Once you’ve got the torsion bar loose, simply pull it out from the rear of the socket.
NOTE: On some cars, especially those in areas that get snow, you may need to heat the rear socket to convince it to release the torsion bar. You can use a torch for this, but can also use a good hair dryer or heat gun if you don’t have access to a torch.
Step 6: Install the New Torsion Bar
Some new torsion bar kits only come with the torsion bars themselves, while others contain everything: new torsion bars, adjuster bolts and plates, and boots. If yours came with everything, remove the adjuster bolt and plate and replace them with the new hardware. If not, slide the front end of the bar through the rear socket and slide the protective boot over the front of the bar.
Apply a light coating of axle or bearing grease in both sockets after thoroughly cleaning out the old grease. Push the bar from the rear until it is firmly seated in the front socket. Use a flat punch or a dowel against the rear end of the torsion bar and give it a firm (but not hard) smack to ensure that the bar is properly seated front and rear. Install the new C-clip. Make sure the boot is firmly seated against the front of the frame. Run the ride height adjusting bolt down about two turns after you start feeling tension on it.
Step 7: Adjust the Ride Height
If you’re looking for factory specifications here, I can’t help you. I set ride height on all my cars as low as I can without scraping and still being able to turn the wheel from lock-to-lock. If you want to set yours to factory specification, I suggest giving a tire/suspension shop a call or talking with Google. Either way, get your tape measure handy.
Get the car so the wheels are back on the ground and bounce (HARD) on both front fenders and jump off quickly (Jounce test). You want to set the car’s suspension again. Now, adjust the torsion bars to a ride height that you like. Use the tape measure at the lower control arm pivot point to the ground to make sure you have the same height left and right. If not, adjust until you do.
Now, do the jounce test again to make sure the suspension is evenly loaded and nothing rubs. Turn the wheel to one side until the steering wheel locks and check the clearance in the wheel wells. Turn the wheels the other direction fully and check again. Measure the ride height again to make sure both sides are equal.
Whether or not you have significantly changed the car’s ride height, you should take it to have the alignment checked. If you’ve got a camber gauge, do that yourself. Now, drive it like you stole it!
See you on the track!