Here is something we have noticed with some aftermarket brake cylinders. The design of the rear brake cylinder on the TD and TF is a one piston cylinder, different than the two piston rear brake cylinder of the TC. Because it is a one piston cylinder, the braking system requires that the wheel cylinder be able to slide back and forth on the backing plate. The initial pressure on the brake pedal pushes the piston out of the cylinder and pushes the lower brake shoe into contact with the brake drum. Once the lower brake shoe contacts the drum, continued pressure on the pedal forces the piston out further, and causes the cylinder to slide upwards, pressing the upper brake shoe into contact with the drum, thus applying the full braking force to the drum. If the wheel cylinder is not able to slide forwards and backwards in the backing plate, only one brake shoe will be pushed into braking contact with the brake drum, giving much reduced braking force at the rear wheels.
Conversations with our customers has shown us that some aftermarket rear brake cylinders are cast in such a way that they do not slide in the opening in the backing plate on the TD and TF. This apparently can be remedied by filing the ‘notch’ in the bottom of the cylinder wider until the correct fit is obtained. This is not an acceptable solution for a system so important as braking. The rear brake cylinders that we sell for the TD and TF are cast correctly so that they easily slide back and forth in the backing plate, providing for correct functioning of the braking system without any user modifications.
Backing plate showing slot for brake cylinder.
Brake cylinder centered
Brake cylinder to the right (top)
Brake cylinder to the left (bottom)
Bad brake cylinder (stuck to the left, does not slide)