“No Grease” S-Cam Composite Bushings Two major concerns of maintenance professionals are performance of parts and vehicle safety. Historically, the bushings used on the air brakes of busses, trucks and tractor trailers have led a rather uneventful existence. Most of the bushings are made of nylon plastic and others are made from brass. These bushings can be made well, but there is a major problem or draw back in using them: they require grease to work properly. Moreover, the grease must be periodically reapplied during the service life of the vehicle. Surprisingly, it is this grease that causes the major safety hazards. The grease leaks from the seals and contaminates the brake linings, causing several serious hazardous events to occur. Contaminated linings develop a glaze which greatly reduces the braking forces available to stop the vehicle. Glazed drums also overheat and crack, weakening the part and compromising safety. Glazing also greatly shortens the life of the lining and the expensive drums. Once glazing has occurred, the braking forces are different on each side of the vehicle creating a serious hazard on highways and icy roads. Brakes and tires on the side experiencing the higher braking load have greater wear. In addition, glazed linings/drums produce very loud noises (brake squeal), creating a public nuisance (noise pollution) both to riders and the public in general— especially people located or living near bus stops. These problems and others have been solved by a new class of S-camshaft bushing that does not require any grease. These new bushings are made from a plastic that will never melt; even red hot brakes won’t melt them. Therefore, they are temperature safe. The same cannot be said of nylon plastic bushings that are now in use. Nylon plastic can melt and cause the S-camshaft to lock up, preventing brake release. Bushings made from brass won’t melt, but they require grease to operate; and the hazards of grease have been discussed above.
These new non-meltable plastic bushings present multiple advantages: a reduction in parts wear, and a reduction in required maintenance. Both advantages are described below.
Reduced parts wear. The new “S” Cam Etcom composite bushings have dry-type lubricants mixed into the plastic so that it is always available on the bushing surface. This new type of bushing constantly lubricates itself and the metal S-camshaft, reducing friction and preventing wear of the metal surface. As an added benefit, the special lubricants in the new non-meltable plastic bushings will actually polish the surface of the camshaft. This typically extends the life of the camshaft and is more than double the life of a typical brass bushing. This feature alone will reduce the purchases of S-camshafts by at least 50% or more. This can also reduce the need to purchase linings and drums by extending their life as well. As well as reduce maintenance labor costs. By contrast, glass fibers are extensively used in the nylon plastic bushings. Glass actually abrades the surface of the S-camshaft, which wears out the shaft in six to eight months. there are no glass fibers in our “S” Cam Bushings. Reduced maintenance. Brakes using the new type of bushings will give at least twice the life to your brakes vs. using the old bushings. Moreover, with the elimination of grease, we have eliminated a step which would create down-time for the vehicle every time re-greasing was needed. The cost savings are obvious because mechanics can be assigned other duties and your trucks aren’t being taken out of service but are on the road making money.
In over 85% of the trucks tested, there was up to a 40% braking variation from one side of the axle to the other.*
In summary, a new type of non-meltable plastic bushing is now available to solve the problems associated with brake maintenance and safety. The new “S” Cam Etcom composite bushing will not melt, needs no lubrication, reduces maintenance hours and parts costs, enhances safety and reduces long service hours; all this for very little cost. For further information please get in touch with us by going to our Contact page on our website. We look forward to hearing from you.
*Referenced from test company—weighing station “Long Life No Grease Bushings” TM