When replacing an engine, it is usually necessary to rearrange the pulley, which sometimes causes certain difficulties. There are several ways to confidently remove the pulley from the shaft without effort and time.
The method for removing a pulley very often depends on the type of fit and the type of mechanical mating. In most cases, it is enough to tap with a hammer at diametrically opposite ends of the pulley to get it off the seat, but time and corrosion can play a cruel joke. In this case, one cannot do without appropriate techniques and devices.
Removing Mechanically Attached Pulleys
Low-power motors often have a spline-free pulley fit. In these cases, the pulley is held against displacement by a retaining ring or washer, or by a threaded connection. In these cases, it is sufficient to unscrew the fixing nuts and remove the circlip. Reusable scalloped rings can also be used, which will either have to be chopped off or leveled for a long time in place with an awl and screwdriver.
Thermal pulley removal
Sometimes it is enough to slightly heat it to remove the pulley. As the temperature rises, the metal expands, which weakens the degree of pressing. If the pulley was set on the shaft by preheating, then the specified removal procedure simply cannot be dispensed with: the shaft diameter is a fraction of a millimeter larger than the hole in the pulley, due to which the degree of pressing is too high.
The pulley is heated from the edges, gradually tapping it from different sides towards the end of the shaft. In this situation, indirect heating of the shaft should not be allowed, otherwise it will also be subject to linear expansion and will clamp the pulley even more. If overheating occurs, the connection must be allowed to cool, and then repeat the procedure again. With a large seat width, several heating attempts are required.
Removing the pulley with a puller
Often the pulley can be removed with a simple puller. It is a thick metal plate with a hole in the center. A large nut is welded coaxially to one of the plate planes. On one line passing through the central hole, small slots are made in the plate. To use the puller, you will also need a bolt for the size of the nut welded to the puller and two smaller bolts with large washers.
Two holes must be drilled into the pulley, located on a line through its center. In these holes, a thread is cut with a single-pass tap, according to the diameter of which the bolts for the puller are selected. There is a centering groove in the shafts of the electric motor, in which it is necessary to fix the ball from the bearing of the required size with the help of thick grease. The central bolt of the puller will also have to be processed: a spherical recess must be made at its end.
The puller is attached to the pulley with bolts through the slots and threaded into the threaded holes. The center bolt rests on a ball fixed in the centering groove of the shaft. In the process of screwing in, the bolt will unlock the puller from the shaft, so that the pulley will be displaced from the seat. If there is not enough bolt travel to fully displace the pulley, several large nuts should be placed under the side bolts.
