This SAE Recommended Practice applies to S-CAM, Wedge, and Disc air brake actuators where the stroke can be measured without disassembly from the brake.
Field Inspections on Spring Brake actuators with many years in field are often very corroded and it is difficult to read text that may have been stamped into the spring housing. Alternate methods of affixing a tag or label to the spring brake often fail over time as the tags and or labels fall off either from impact or corrosion. Some Spring Brake Actuators have an Aluminum Center Section that can have the marking permanently cast into the part. This marking remains readable despite excessive corrosion and cannot come loose.
This new revision to the recommended practice allows manufactures to have the option of placing the stroke marking on the center section. The location is similar to the servicing instructions from SAE J1817, but is applicable for all sizes. This should make adoption of this guideline easier for manufactures that use a different center section for each stroke size, but the same Spring Housing. Manufactures that use a different Spring Housing for each stroke size may also maintain the current stroke marking location on the spring housing.