Bottas raised concerns over Mercedes' pit stops before Monaco

How will a qualifying sprint race work to determine the grid? (1:10)

Nate Saunders is pleased with F1's "proactive" decision to have a qualifying sprint race in three of the 2021 events. (1:10)

Valtteri Bottas says he raised concerns about the standards of Mercedes' pit stops before a machined wheel nut forced him into retirement at the Monaco Grand Prix.

Bottas holds the dubious honour of Formula One's longest pit stop after it took Mercedes 43 hours to remove the front right wheel from his car following a botched tyre change in Monaco.

The wheel gun used by the mechanic connected at an angle with the wheel nut, meaning its socket machined the metal away from the teeth of the wheel nut rather than connecting with them.

It was impossible for Mercedes to remove the wheel from the car in Monaco, and it was only released after it had been sent back to the factory in the U.K. where a high-powered Dremel tool was used to cut through the wheel nut.

Bottas was running in a solid second place before the pit stop issue, meaning the mistake likely cost him 18 points in the championship.

"We always analyze everything very openly -- not blaming any people but really analyzing things honestly and admitting weaknesses, which was the pit stop." Bottas said ahead of this weekend's Azerbaijan Grand Prix.

"As a matter of fact, it was one of my concerns already a few weeks ago, that I raised with the team.

"So it didn't come from somewhere out of the blue, we knew that we are not perfect in pit stops as we've seen, and also other areas like tyre warm up in qualifying."

In the aftermath of the race, Mercedes team boss Toto Wolff said Bottas had stopped beyond his markers in the pit box, perhaps contributing to the wheel gun going on at an incorrect angle.

Bottas was surprised by those comments, saying footage of the pit stop indicated he was relatively accurate in coming to a halt at the right point.

Asked if he was surprised by Wolff's comments, Bottas said: "Yes, I was surprised. I saw the video, and for me it was pretty spot on where I stopped. Yes, I was quite surprised.

"Of course, I want to see all the reports about where I stopped, and I think I was like two or three centimeters off the central line. And if you get that accuracy normally, it's pretty good. You know, you can easily swing by 10/15 centimeters so I thought it was pretty spot on.

"But it's pretty normal debrief, to be honest, and of course we had discussions, the week after, still with my engineers, analyzing everything and at the factory they've been full gas, understanding everything.

"So, it is nothing unusual for us, it was just a bigger setback than some other weekends in terms of result but pretty normal procedure otherwise."

Bottas, who is now 58 points behind championship leader Max Verstappen in the drivers' standings, also gave some insight into how he had dealt with the disappointment of retiring from second place.

"Personally, for me, it took a couple of days, I've got to say.

"It has not been the best start of the season and that kind of issue, when it hits you when your target is to get some good points is disappointing but I got over it, I've got my own ways of getting through it, and I'm keen to race again."