Have two plugs, such as old pencils, ready to fit the pipes. Unscrew the pipe connections and plug them at once.

As shown in Figure 1, sealing devices come in two types: contact and non-contact.
Oil seals are among the major contact type sealing devices.
ERIKS type R (type A according to the DIN standard) is identical in shape to type M, but has a rubber outer case with metal reinforcement on the inside. The rubber creates a good seal in the housing, even if the housing has suffered minor damage or is not in its best condition for other reasons. The RST version has a dust lip. These types are often chosen to replace a type with a metal outer case because they are easier to install and can cope with minor damage to the groove, such as scratches.
The hardness of the shaft determines how long the seal will last. A shaft should have a Rockwell hardness of 30 or more. It prevents the seal from getting damaged when it’s exposed to abrasive agents.
Figure 14.1. Shaft seals (DuPont Dow Elastomers).
3、About production