It is recommended not to back down when riding control

Which wheel balancer is right for your store?

Subaru wheel nut replacement is rusty

The updated ASE Renewal App provides the benefits of recertification

It is recommended not to back down when riding control

Which wheel balancer is right for your store?

Subaru wheel nut replacement is rusty

The updated ASE Renewal App provides the benefits of recertification

Sponsored by Bolt On Technology

Sponsored by Cloies Gear & Products, Inc.

Building customer loyalty: why oil changes are important

Building customer loyalty in any business is challenging. Getting customers back to the car repair shop is the most difficult task for car owners. If a store can crack this code, they will seize current and future repair and maintenance opportunities. The only inherent opportunity for each vehicle to increase customer loyalty is engine oil and functional fluid services.

In this one-hour webinar, our experts will discuss how they can establish oil change and vehicle maintenance plans to maintain customer return rates and help maintain healthy profit margins.

Speaker John Stotz, Senior Marketing Manager of Sheng Brand Lubricants. Andrew Markel, Content Director, ShopOwner

Sponsored by Bolt On Technology

Brake & Front End responds to emerging trends in the field of chassis repairs by providing application-specific technical information and solutions, thereby providing services to repair shops that perform a large number of chassis repairs. By subscribing, you will receive the ShopOwner digital magazine (12 times a year), which contains articles from Brake & Front End and Brake & Front End e-newsletters (twice a week). Today is ready for you to access digital editions, competitions, news and more!

Brake & Front End responds to emerging trends in the field of chassis repairs by providing application-specific technical information and solutions, thereby providing services to repair shops that perform a large number of chassis repairs. By subscribing, you will receive the ShopOwner digital magazine (12 times a year), which contains articles from Brake & Front End and Brake & Front End e-newsletters (twice a week). Today is ready for you to access digital editions, competitions, news and more!

It was Vange Proimos' experience as a technology and shop owner that provided a lot of information about his success as the CEO of AP Emissions.

Don't settle for "almost"-the location of the engine's manufacturing or remanufacturing is important. Sponsored by ACDelco.

GM gearboxes and transfer cases are unique to each vehicle. This video is sponsored by ACDelco.

Don't settle for "almost"-the location of the engine's manufacturing or remanufacturing is important. Sponsored by ACDelco.

Click here to view past questions.

Earl MacPherson’s struts eliminate the complexity of the suspension in one way, but change the geometry of the vehicle in other ways.

Macpherson-style pillars were first used in automobiles in the 1960s. Since then, pillars have been installed in everything from compact cars to full-size trucks. The pillar as we know it today was invented by Earl MacPherson as an alternative to the short and long arm suspension.

Accountants like Earle's pillars because they eliminate the suspension parts. Engineers like pillars because they are the perfect packaging solution for horizontally mounted engines and gearboxes. For stores in the 1970s, pillars brought new service and alignment challenges.

When the suspension is compressed, removing the upper control arm changes the way the camber, caster, and toes increase or decrease. The shorter arm of the traditional short-long-arm suspension works on a tighter arc than the lower long arm, so when the suspension is compressed, a negative camber angle is generated. With MacPherson struts, the camber gain is minimal when the suspension is compressed.

The pillar also changed the steering geometry. The inward tilt of the strut is part of the steering axis tilt (SAI) angle and is determined by the lower ball and upper strut mounts. Tilt backward to determine the backward tilt angle. SAI also helps to set the camber angle when turning.

Another invisible angle is the scrub radius. The scrub radius is the front view distance between the SAI and the center of the wheel contact surface, both of which will theoretically touch the road. It can be positive, negative, or zero. Engineers will optimize SAI and frosting radius to improve steering feel, braking stability and even torque steering.

These angles are why the front suspension must be checked for bent parts when diagnosing steering or tire wear-related issues. This is also the reason why brake tension may be an alignment and suspension problem.

Under extreme forces, the strut may bend near the connection point on the steering knuckle, or the piston rod itself may bend. Joints can also deform and change angles. Either case will cause changes in the camber angle, SAI and scrub radius.

Engineers will also design the shape of the steering knuckle to optimize the SAI, scrub radius, and the force on the damper and spring. For example, if you look at the steering knuckle of a Ford Focus or Volkswagen Golf Mk4-Mk7, it will push the lower mounting point of the strut to the inside. The L-shaped knuckle does allow wider wheels and tires, but it can also control the side load on the dampers and springs. The springs in these applications can be barrel-shaped and contact the upper and lower spring seats in a very specific way. 

If you suspect damage to the suspension, first check the wheel alignment and perform a visual inspection. Assume that the left front suspension fully meets the specifications, while the right front suspension may not meet the specifications. In this case, the lower control arm, tie rod, steering knuckle or pillar on the passenger side may be damaged by the collision. Generally speaking, if the camber angle exceeds the specification and cannot be adjusted, it is entirely possible that the steering knuckle and the pillar are bent.

One of the most challenging items in the diagnosis is the curved support rod. To check the bent pillar shaft, loosen the large shaft nut on the top of each pillar and rotate the shaft 360° while paying attention to the camber angle reading. If the shaft bends even the slightest, the top of the wheel will wobble, and the camber reading will change as the shaft rotates. No change in the camber reading means there is no problem with the pillar. 

Pillars with curved shafts must be replaced because this damage cannot be corrected safely. Attempting to bend a hardened shaft may break it. The only option is to replace the pillars.

The front upper strut mount or plate is essentially a load ball joint with a single axis of rotation. The upper strut installation must allow the spring and strut to rotate when turning. The upper pillar mounting seat is equipped with bearings, which can support the weight of the corners and can withstand side loads. These bearings may be hit and may fail before the pillars. When they do fail, the pillars can cause steering and noise constraints.

The bearings in the plate are sealed components and cannot be lubricated. Therefore, if the bearing plate is rusty, loose, worn, noisy, stuck or damaged, it must be replaced. It should be regarded as a spherical joint when conducting vehicle inspections. 

Since the strut suspension does not gain too much negative camber when compressed, it must use other techniques, such as bushings. Some bushings are like a progressive spring that can change the alignment angle of camber, caster, and forward when the strut suspension is loaded during a turn. Since the bushing is loaded in different directions, the first few millimeters of movement may occur with minimal effort. As the load increases, the bushing will become harder. In addition, the control arm bushing may react differently to loads caused by turning, acceleration, and braking, and loads caused by side loads.

The structure of the casing can be complex to be able to have these advanced qualities. You may see different structures, voids and materials in the casing. Some of these voids can pass through the bushing. Some bushings may have chambers filled with oil or glycol, which are commonly referred to as hydraulic bushings. When loaded, the suspension will pass between the chambers. Since the liquid is not as compressible as a soft component, the movement of the suspension can be controlled more predictably.

Torque steering first appeared in some early front-wheel drive vehicles that used unequal-length drive shafts and strut suspensions. Then, engineers try to adjust the torsional stiffness of the shaft by using hollow shafts and solid shafts in certain applications. Other manufacturers use intermediate shafts to balance the length of the drive shaft to the wheels. Some manufacturers even use electric power steering to counteract torque steering. However, when the engine torque and horsepower reach a certain level, all these technologies have limitations.

The use of traditional strut designs in high-horsepower applications is a solution to torque steering, steering jitter, and braking instability. Although the torque can be balanced using the drive shaft design, the SAI and scrub radius geometry of the traditional strut design may add to the problem. 

The 1990s Toyota Super Strut, General Motors HiPer Strut, and Ford's RevoKnuckle optimized the scrub radius and SAI by mounting the steering knuckle to the side of the pillar using ball joints. Compared with the geometry of the upper strut mount and the lower spherical joint, this makes the steering shaft more upright. Some people call it a dual-path design because the SAI and steering shaft are no longer connected. This reduces the scrub radius and brings it closer to the center of the contact surface. It also allows the use of larger brake and wheel sets.

Other recent strut suspension designs use two lower links, with ball joints connected to the steering knuckle. These linkages or control arms have different mounting points and lengths to change the geometry of the suspension when cornering or braking. A recent example is the current generation Ford Mustang launched in 2015. 

Compared with short boom suspensions, strut suspensions generally have tighter alignment angle tolerances. The amount or range of adjustment may also be limited by the number of installation points on the vehicle. In addition, because the pillar suspension has fewer parts, it is more likely that one adjustment will affect the other. This is usually the case with camber adjustment, which can change the toe angle of the strut suspension. Some calibration professionals call this "crosstalk."

Another factor to consider is the one-piece fuselage and subframe. Most vehicles use strut towers as part of a one-piece body and a subframe for mounting the lower control arm. Although the subframe rarely moves due to a collision, or the mounting seat and bushing are degraded. 

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