For a vehicle to steer straight and handle safely, wheel alignment needs to be within certain specifications. When a vehicle is in the service bay, technicians need to take the time to make sure the vehicle still has the proper toe, camber and caster angle settings. In addition to handling and safety issues, a properly aligned vehicle would extend the life of the tyres.
Unfortunately, not all of the vehicles are easy to align. According to one alignment equipment manufacturer, 32 per cent of vehicles on the road today require rear shims for camber and toe adjustment. Shops that choose not to work on these hard-to-align vehicles are not only losing the immediate business, but by sending the customer down the road to a competitor, may be losing the customer for good.
To help cure these vehicles’ alignment problems, there are aftermarket alignment aids, such as shims, that would allow the technician to make the necessary alignment corrections. While shims could correct a lot of alignment problems, don’t rely on them to cure every problem. Before wasting a lot of time and effort finding the right shim to use, if camber is less than specifications, be sure to check the ride height. If the springs are below minimum ride-height specifications, forget about using shims. To restore safe handling on such a vehicle, the springs should be replaced.
Types of Shim
There are several types of rear shims available that would assist in making camber and toe corrections on FWD (front wheel drive) cars and minivans. Make sure you are familiar with these types of shims.
Half Shims – These come in various sizes and thickness for use on General Motors, Chrysler, Volkswagen and Audi applications. Half shims could be used to make both camber and toe corrections. Most of these shims are metal and could be slid into place without having to unbolt and remove the rear spindle or wheel bearing.
The downside is that the half shim creates a small crevice into which dirt and water could penetrate. In addition, they do not provide as much support as a full-contact shim. The most common mistake made when using a half shim is installing it in the wrong position. Be sure to place it between the brake backing plate and axle. Placing it between the brake backing plate and hub could result in braking problems.
Full-Contact Shims – These come in various configurations and sizes. In addition, they come in both metal and plastic and different bolt patterns are needed for different applications. Full-contact shims could be used to provide .25 up to 1.5 degrees of camber or toe correction depending on the thickness of the shim.
Using a full-contact shim usually requires completely removing the spindle or wheel bearing and brake backing plate so the shim could be installed between the backing plate and axle or trailing arm. If the vehicle being serviced is equipped with anti-lock brakes, pay special attention to the wheel-speed sensor wiring. If not careful, this wiring could be easily damaged.
Two-Piece Adjustable Shims – A relatively few number of shims could fit a wide range of applications. Most two-piece adjustable shims are plastic. Installation is the same as with full-contact shims, except that adjustable shims must first be set or trimmed to achieve the desired amount of camber or toe correction.
When installing adjustable two-piece shims, make sure the shim faces the proper direction. On one side of the vehicle, the shim may face in, while on the other side it may face out. Positioning it the wrong way would give you just the opposite effect you are after.
Alignment Equipment
Today’s high-tech alignment equipment could take a lot of the guesswork out of shim installation. The technician could call up the make and model of vehicle he is working on and with the click of his pointer, he could change the orientation angle of the shim and see the resulting change in camber and toe. The alignment machine makes all the calculations for the technician and presents the results in colourful animation.
Not only could the technician use this information to choose the correct shim and obtain installation instructions, he could also use the information provided by this equipment to help explain the needed service to the vehicle owner and to educate him on exactly what needs to be done to correct the problem. By printing out the diagrams from the monitor, the technician could show the vehicle owner exactly what is found out in the service bay.
If you have the right equipment and the knowledge to use it, don’t be afraid to charge for your time. The ability to return these hard-to-align vehicles to proper operating condition is something for which you should be fairly paid. Armed with the colour printouts mentioned earlier, the technician or service writer could explain to the customer why additional charges were necessary.
With the right equipment and training, technicians are able to align these vehicles that were once viewed as being unalignable. The key is keeping up with the new technology that is available in the aftermarket. It seems that as fast as automakers could release a new alignment system, somebody comes up with the needed fix.
To ensure the Malaysian tyre servicing providers are equipped with relevant knowledge and skills, Newera Equipment Supply Sdn Bhd, the Hunter sole distributor in Malaysia, has brought in not only the advanced alignment technology from Hunter but also the EZ Shim. With the EZ Shim kit, rear toe and camber are now adjustable, allowing the tyre servicing providers to provide precision alignment for maximum performance and prevent uneven tyre wear.
现代设备引进车轮定位垫片
轻易校正前或后车轮
为了让一辆汽车能够直行和安全操控，车轮需要符合特定的规格。当一辆汽车在维修间时，技术人员必须确保车辆的前束、外倾及后倾角的正确设置。在操控和安全问题之外，正确的车轮定位可延长轮胎的使用寿命。
不幸的是并非所有的车辆都能轻易地进行四轮定位。据一家汽车四轮定位仪制造商表示，今天有32%的车子后轮需要定位垫片来调整外倾与前束角。那些选择不处理难于定位车辆的汽车轮胎服务中心，事实上不仅失去生意，还等于是将客户送到附近竞争对手的手里，甚至可能永远失去客户。
为了协助解决这些汽车的四轮定位问题，我们可以采用后市场的四轮定位辅助，如车轮定位垫片， 让技术人员进行所需要的车轮定位。虽然车轮定位垫片能够校正许多定位问题，但却无法解决每一个问题。在浪费许多时间和精力选择适合的垫片前，如果外倾角小于规格，那么就一定要检查车身高度。如果弹簧低于最低的车身高度规格，就别使用垫片。为了恢复汽车的操控安全，需要更换弹簧。
垫片的种类
目前，市场上有各种协助调整前轮驱动汽车和迷你货车的前束和外倾后车轮垫片。确保你熟悉这些垫片种类。
半垫片（Half Shims）：适用于通用汽车、克莱斯勒、大众及奥迪，拥有各种尺寸和厚度。半垫片能够用来校正外倾和前束。这些垫片都是金属打造而成，无需松开和取下后部主轴或车轮轴承，就能滑入到位。
半垫片的缺点是会导致小裂缝，让灰尘和水渗透进来。此外，它们不像全接触垫片那样能够提供比较多的支持。采用半垫片的最大错误是将它安装在错误的位置。一定要将它安装在制动器背板和车轴之间，将它安装在制动器背板和轮毂之间，将产生制动问题。
全接触垫片（Full Contact Shims）：一般拥有各种规格和尺寸。它们有金属和塑料两种材质，不同的螺栓款型供不同的应用。全接触垫片能用来校正0.25 至1.5度的外倾或前束，视该垫片的厚度而有所不同。
采用全接触垫片，需要完全松开主轴或车轮轴承，将它安装在制动背板和车轴或拖曳臂之间。如果被维修的汽车采用的是防锁制动器，就要格外注意轮速传感器接线。如果不够小心，会对这些接线造成损伤。
两片可调垫片（Two-Piece Shims）-适用于广泛应用的相对少数垫片。大部分的两片可调垫片是塑料制成的。安装方式与全接触垫片一样，除了它必须加以设置或修剪，以达到想要的外倾和前束调整值。
在安装可调的两片垫片时，确保该垫片面向正确的方向。在车辆的一侧，它必须朝内，而在另一侧，它则必须朝外。若将它安装在错误的位置上，你将适得其反。
定位设备
今天的高科技四轮定位仪可消除安装垫片时的各种猜测。技术人员能够找出车辆厂牌和型号，只要采用鼠标来点击，就能改变垫片角度定位，看到外倾和前束的变化。该四轮定位仪将为技术人员进行所有的计算工作，并以彩色动画呈现结果。
技术人员不仅能够采用该信息来选择适合的垫片，取得安装指示，还可采用该设备所提供的信息向车主解释为什么需要这项服务。技术员只要将屏幕上的图表打印出来，便能让车主看到他们在进行维修时发现的问题。
如果你拥有采用它的正确设备和知识，就能要求客户为你为他们付出的时间付费。他们应支付你将难以进行四轮定位的车子，调整至正确运行操作情况的能力。有了上述的彩色打印，技术人员或服务人员就能为客户解释为什么他们需要支付额外的服务费用。
有了正确的设备和培训，技术人员就能为过去那些被认为无法进行车轮定位的车子进行四轮定位服务。显然，最主要的关键莫过于是懂得采用后市场的新技术。看来只要汽车制造商发布一个新的定位系统， 就会有人提出所需要的修复。
为了确保马来西亚轮胎服务供应者拥有相关的知识和技能，现代轮胎设备有限公司，也就是Hunter独家经销商不仅引进了Hunter的先进四轮定位技术，还有EZ垫片。有了EZ垫片套件，后束角和外倾角都能加以调整，轮胎服务供应者也就能提供准确的四轮胎定位服务，为客户带来最佳的性能和避免不均匀的轮胎磨耗。
