A.5 B.10 C.15 D.20
A.1至2 B.2至3 C.3至6 D.4至7
A.用汽油清洗閥芯與閥座 B.當(dāng)腐蝕斑點(diǎn)較多、較深時(shí),可直接用細(xì)砂研磨 C.將閥芯、閥座研磨面清洗干凈,做密封性試驗(yàn) D.用零號(hào)細(xì)砂布打磨閥芯、閥座表面的銹蝕、斑點(diǎn)