Romain Grosjean was hoping that the team's decision to switch brake component suppliers from Brembo to Carbone Industrie would address a lot of the problems he'd been experiencing on the VF17.
But judging from the French driver's team radio messages in Friday practice in Sochi, the change has made little difference.
"We’ve got very little grip. We’re really struggling with the balance. We had some issues, as well, with the brakes over the long runs," he admitted at the end of the day.
"We need to look at what we can do better with them.
"Generally, it’s just been a very difficult Friday," he sighed. "The car didn’t perform well – very low grip on low fuel and high fuel."
Haas F1 boss Guenther Steiner said that the team had yet to make any decision on whether to stay with the new brake components, or revert to the old ones.
"We still haven’t got all the results yet, as we need to go through data," he explained.
"I would say the issues with the brakes were mainly because they’re new to us. We need to find out how they work. Going through the data, we will decide tomorrow what we’re doing and how we continue.
"All in all, we had pretty fruitful sessions. We did a lot of laps and we learned a lot. Now we need to get the best out of what we learned for tomorrow to go into qualifying."
In contrast to Grosjean's day, his team mate Kevin Magnussen had a somewhat better time of it in free practice.
"I’m quite happy," said the Dane. "We got through the day without any problems on the car. We got the whole program done, so that’s very satisfying.
"The early feeling is good with the car. We need to look at a few issues on the balance, normal stuff like that, but the baseline is quite good.
|The balance of the track is evolving in each session, but the balance in the car is similar, so that’s a good sign.
"We’ll keep working and try and iron out the small balance issues that we have."
GALLERY: All the pictures from Friday in Sochi
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