![]() This can cause the rear suspension to squat on acceleration. Sometimes the upper and lower lines are parallel and don’t intersect. We won’t get into all the details around this, as it is a complex issue. The intersection point is called the instant center for the rear suspension. Ideally, the extended upper and lower lines will intersect at some point within the wheelbase of the car. Next, extend another similar line through the upper control arm mounting points. Let’s start by drawing an imaginary line from the lower rear mounting point of the lower control arm to the front control arm mounting point and extending that line forward. This is where the rear suspension action gets a little complicated. The control arms prevent the axle housing from moving, sending the power through the axles to the rear tires. The upper control arms immediately go into tension (pulled apart), while the lower control arms are placed in compression. If we view the rear axle assembly from the passenger side of the car, when torque is applied the pinion also attempts to climb the ring gear, which then attempts to rotate the pinion upward. This is why non-positraction equipped cars always spin the right rear tire. First, the axle housing (as viewed from the rear of the car) attempts to spin counter-clockwise, lifting the right rear tire and forcing the left rear tire into the pavement. When power is applied to the rear axle, the pinion gear tries to climb the ring gear, creating multiple forces. This forms a simple triangle that eliminates the need for a Watts Link or Panhard bar to laterally locate the housing under the car. ![]() The upper arms also are splayed at an outward angle from the top. The upper arms are connected to a crossmember in the upper part of the frame and connect to the top portion of the axle housing. The lower trailing arms bolt to the lower portion of the frame and connect underneath the rear axle. A Chevelle system uses coil springs to support the vehicle weight and also employs upper and lower trailing arms. Sometimes a solution creates other problems and therefore isn’t the best approach.īefore we get into these parts, let’s look at exactly how the Chevelle rear suspension functions. We’ll take a look at these methods and evaluate them based on how well they work. The aftermarket offers several additional approaches that do work, though some are simpler than others. If wheel hop is eliminated, then at least you will know that a lower ride height may solve the problem. You might try adding weight to the trunk, which accomplishes two things-it temporarily lowers the car’s ride height and adds weight over the rear tires, which can improve traction. This kills the spring, and is not a good way to lower a car. Don’t try torching the springs to shorten them. Because the rear springs on a ’69 Chevelle use a pigtail on both ends, the springs cannot be cut. This may require different rear springs to lower the ride height.Įarlier ’64-’67 Chevelle rear springs employed an open wire end on the upper part of the spring that can be trimmed to lower the car. From your description, it’s possible that even with all the air bled from the air shocks the car still may sit too high. When the ride height is raised, the front mounting point for the trailing arm will be higher than the rear mounting point at the rear axle housing. The easiest way to establish “how low is too low?” is to look at the lower trailing arm.Ī great starting place is to ensure that the lower trailing arms are parallel to the ground. Rear air shocks were a common addition back then, and we learned quickly that lowering the rear ride height often solved the wheel hop problem. Way back in the day, we discovered that raising the rear ride height can create some violent wheel hop. I’ve owned Chevelles since 1971, and I have experienced this exact issue. Part of the solution is something as simple as ride height. Jeff Smith: This is a common problem with the Chevelle non-parallel, four-link coil spring rear suspension, but don’t despair-there are a couple of easy fixes. Everybody’s saying their product will stop wheel hop, but nothing so far has worked. ![]() Will it stop if I put the QA-1 traction bars on it? I’m trying to keep the car as original looking as possible and also not throw away a lot of money. I changed all the upper and lower bushings to poly but still have wheel hop. I tried letting the air out of the shocks, but it still hops. When I do a burnout I have bad wheel hop. I have a 1969 Chevelle 396 4-speed, 3.55:1 rear ratio, F41 Chevy suspension on air shocks.
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