The main locations to install hydraulic cylinder packings and seals are around the cylinder piston and at the rod end of the cylinder. Seals around the system prevent internal cylinder leakage, while seals and packings at the rod end prevent external leakage. Rod wipers prevent harmful debris from entering the cylinder. If you are not repacking the cylinder with a seal kit designed specifically for that cylinder, you'll have to take accurate measurements of several cylinder dimensions to pick the right seals and packings. You can only take the required measurements from a fully disassembled hydraulic cylinder.
Things You'll Need
- Micrometer caliper
- Bore gauge
- Depth gauge
Rod Seals and Rod Wipers
Measure the rod diameter with a micrometer caliper. Adjust the jaws so that they fit around the rod and read the measurement.
Measure the cylinder bore with a bore gauge. The cylinder bore is the diameter of the inside of the hydraulic cylinder. The anvils of the bore gauge fit inside the cylinder. Adjust them outward until they reach the interior sides of the cylinder.
Measure the diameter of the groove in the cylinder housing that will house the seal. This diameter will be slightly larger than the cylinder bore. You may have to use a depth gauge to measure the difference between the cylinder bore and the grove diameter, then add the depth of the groove to the cylinder bore.
Measure the width of the seal groove. You can use calipers for this if the groove is accessible. If you cannot take this measurement directly from the cylinder, measure the old seal with the micrometer caliper.
Measure the rod diameter.
Measure the cylinder bore with a bore gauge.
Measure the seal's groove diameter of the the cylinder housing.
Measure the groove on the cylinder piston. Measure its depth and width.
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