BARCELONA, Spain -- Haas has decided to push back its planned test of Carbon Industrie brakes to later in the season as continues to work on solving "inconsistency" with its Brembo supply.

Brakes were a major weakness for Haas in 2016, suffering major issues with its Brembo brakes in the final races of the campaign. The team tested Carbon Industrie brakes at the penultimate race in Brazil to identify if the problems were with Brembo or its Dallara-built chassis, and planned to run a parallel programme between the two manufacturers in winter testing.

However, this week it has run only Brembo, though team boss Guenther Steiner admits the team has not completely solved last year's problems.

"We are not completely done with the brakes," Steiner said after the fourth day of testing at the Circuit de Catalunya. "With the brakes our biggest problem is our inconsistency, again, we have sometimes a brake which we are really happy with and the drivers are really happy with and then we get a set which we are not happy with."

"You lose a lot of time because it's not only to change it, the driver loses the confidence and then when you put the next one on he needs to get into a state again that he's confident with what he gets. So we are not done with it yet.

"We had good brakes on Tuesday and we had good brakes today but yesterday that was one of our problems. We weren't consistent with the brakes so we had to put another set of brakes on. I would say it throws the driver off his focus when the brake doesn't work consistent, he's like 'oh is it coming back?'"

Haas will also run Brembo brakes for the four days of testing next week, with Steiner admitting the team was too late in sorting a CI supply for Barcelona.

When asked if it was a case of one of the options being more consistent than another, he replied: "No with the other one we haven't tested enough yet to know whether they are consistent or not. We had a test last year but we haven't come to a conclusion and we still need to test them for this year because we were late with the sign off, so they have to use new brakes because the discs are thicker, so we haven't got them yet."

Steiner then confirmed it plans to test Carbon Industrie later this season, adding: "We just don't know exactly when. Or which race we put them on."