Good morning. This is Saul Reisman here at Saul’s Automotive. One other component that we’re going to talk about in your suspension today is the control arm bushings.
Now, this bushing has a pretty significant strength feature to it. Rather than being a basic rubber, hollow bushing design, this bushing is encapsulated in steel. Has an outer sleeve. It has this chamfered edge along the entire inner length of it. The center portion is also steel faced on both sides and has a steel sleeve in the center. This is designed to have a bolt pass through it and hold a pretty extreme amount of torque. When the independent arms of your front end pivot up and down, they’re physically rotating on these joints. So these joints see a tremendous amount of impact force.
As a result, to install these into the pressed hole into the control arm is a pretty serious task. First, we remove the arm from the vehicle. It doesn’t take too long, maybe an hour or so. We then have to take the arm, mount it into a 25-ton press and physically push the old joint out, clean the bore, chamfer the edges and then press this new joint in. The goal of that is to have the tightest fit possible. Any lateral motion between it will result in clunking and bumping every time you hit a crack in the road.
To avoid that, the joints that we install for these control arm bushings are actually tapered and of slightly larger diameter on the second half than on the first half. This allows the joint itself to get centered at the correct diameter that the factory provided for the first half of engagement, and then as we press it, we actually enlarge the hole by a millimeter and a half, so that the second portion stretches that hole out and provides a tighter-than-factory fit.
If you’ve got a Denver car that’s more than 15 years old, these joints, I can almost guarantee, are starting to rot, crack and fatigue. If you’ve got a classic or a collector car that’s more than 30 years old, you already know that the bushings are the number-one cause of suspension failures.
Here at Saul’s Automotive, the suspension bushings we install are not only an over-chamfered design, but they also have a raised ridge. This allows us to press the joint in until it physically bottoms out into the other side. Last but not least, these bushings additionally have a feature here on the end facing. Where you see these hash marks moving across the facing of the joint, these are designed so that when we install a cam alignment bolt into the vehicle, they generate friction, so that if this joint is installed in the vehicle, and let’s say five years down the road it’s starting to wear and has an uneven characteristic, becomes softer on the top and bottom than on the sides, you can bring it in, we can rotate the joints, turn them 90 degrees, and then continue yet another five years of operation out of ‘em, as if they were new.
This is something that no other bushing manufacturer produces other than Moog, who is one of the largest and most commonly used in NASCAR and other racing componentry. These are the only bushings we install here at Saul’s Automotive. If you have any clunking, bumping, chattering, noise like a wheel hop or a wheel bounce when you’re hittin’ bumps at low speeds, this is most likely the culprit.
Similar to the joints we were talking about this morning, many vehicles have a significant amount of these rubber bushings in the front end. Your typical sedan will have a total of four lower control arm bushings, and as many as eight upper control arm bushings, while most pickups and SUVs have a total of eight upper and eight lower control arm bushings on each end of the vehicle. This means there can be up to 32 of these in your vehicle.
Here at Saul’s Automotive, we’re more than happy to test and inspect these free of charge. That way we can accurately determine the condition of them before they start to fail and lead to other component failures with them. Because these will rot out and physically deteriorate, when they have no rubber left, the outer diameter and the inner diameter essentially become the same, and instead of the bolt resting tightly in the center, it’s allowed to move up and down, not only creating noise that you don’t like to hear, but it’s actually changing the physics characteristic of this component.
When a bolt is placed through the center of it, it’s acting as a single-shear application, meaning a single shear would need to occur for it to be broken free form its housing. When that bolt is loose and can rotate freely inside that housing, it’s now acting in a dual-shear application. Instead of having one frictional surface, the bolt can actually get cock-eyed and be pivoting on two and hitting both sides. When this happens, literally twice the force is exerted on the bolt. This will break the bolt and allow the suspension to break free from the vehicle. That is literally when we say “pulling a Blues Brothers” as the doors, the windows, the everything fall off the car. The suspension components at that point physically fall off of the vehicle completely.
To prevent that from happening, please come and see us. Let us take a look. Happy to see the condition of theses bushings, show you exactly how much wear is on each one and give you a few tips to help keep these livin’ a little longer.
If you’ve got a vehicle that’s got clunks or bumps or noises in its front end, this probably is your culprit. Stop by Saul’s Automotive or give us a call at 303-919-7769 seven days a week.
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