spare parts; replacement parts
Refers to extra components kept on hand for repair or replacement, especially in machinery, electronics, or vehicles.
Spare parts for this machine are no longer produced.
I ordered spare parts in case of breakdown.
交換部品 emphasizes parts intended for exchange or replacement, while 予備部品 focuses on parts kept in reserve.
スペアパーツ is a direct loanword from English 'spare parts' and is used similarly, but 予備部品 is the native Japanese term.
Compound of 予備 (yobi, 'reserve, spare') and 部品 (buhin, 'parts, components').