2. Unscrew the 4 fixing bolts of the cover and remove it together with the gasket. After that, you can pull out the rotors, because. the inner rotor has a sliding key that engages with the drive shaft key. Rinse the rotors in kerosene and wipe them dry with a lint-free cloth. Clean the pump housing with a cloth soaked in kerosene, and wipe it dry with a clean, lint-free cloth.
3. Inspect the pump housing and rotors for damage, scratches and obvious signs of wear. Typically, pumps of this type have a long service life, but over time they wear out and their performance decreases. In case of severe wear of the rotors or if the pump performance has noticeably decreased, the rotors should be replaced in pairs, but since on an old engine, the pump housing is also likely to be worn out, and the timing cover may also need to be replaced.
4. The pump is assembled in the reverse order. Lubricate all moving parts well with clean engine oil and install the pump cover with a new gasket (see pictures).