When the wheels fall off (come off) something, it goes wrong or fails. It’s used to say that something suddenly stops being successful. (It’s used for saying that things start to fail or go wrong, especially after a period of success.)

Example: The team was leading 3–1 at half-time, but then the wheels came off and they ended up losing the game.

(The Guardian, 2017/3/29)

Barrow delivers Brexit letter without wheels coming off 貝羅順利送出脫歐信

Sir Tim Barrow (on the left), Britain’s ambassador to the EU, delivered the letter that Europe had been waiting for at lunchtime on Wednesday. After 31 years in the diplomatic service, stints as Britain’s envoy to Moscow and Kiev, it was a funny sort of career pinnacle – to become the nation’s most eminent postman.

英國駐歐盟大使提姆貝羅爵士周三午餐時間，週三午餐時分把英國啟動脫歐的信函送到等著的歐盟(總裁Donald Tusk)手裡。對於貝羅這樣擁有外交界31年的資歷，並曾是英國駐莫斯科以及基輔大使的人來說，擔任英國最顯赫的郵差也算是他職業生涯一個有趣的巔峰了。

(White House Patch, 2017/7/30)

Have the Wheels Come Off the White House Wagon? 白宮螺絲鬆了嗎?

(NBC News, 2017/7/27)

Are the Wheels Coming Off Trump’s “Fine-Tuned Machine”?

川普領導的[精準機器]，是否螺絲鬆了?

WASHINGTON — Accusations of incompetency can undermine even the most talented of politicians. Just ask George W. Bush (Iraq war, Hurricane Katrina) or Barack Obama (HealthCare.Gov).

But while the events and news over the last 24 hours seem like just another day for the Trump White House, they expose a level of dysfunction and chaos that could leave a lasting mark for a president who said back in February that he was running a “fine-tuned machine.”

就算是最有天分的政治人物，指控他們無能也會削弱他們(的治理)。這問問老布希或是歐巴馬總統就知道了。過去二十四小時發生在白宮的新聞事件看起來似乎是川普政府很普通的一天，但暴露出來的失能與混亂卻可能在川普任內留下長遠的影響，尤其川普二月時才宣稱他的團隊是[調校精準的機器]。

Photos: Los Angeles Dragnet, Civil Service World, Daily Star