The humps had only just been completed when damage was reported on cars going over them.
Drivers using the road in Melling said they were like "mountains".
On Friday, one councillor claimed humps of the same height were also built in the nearby village of Lunt.
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Questions now need to be asked as to why no visual inspections were done
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Councillor Jack Colbert
Councillor Jack Colbert was inundated with complaints about the bumps, which he said cost about £150,000 to install.
He told BBC News Online: "People told us they looked like a mountain range and that they were absolutely massive.
"Several cars were ripped underneath by the bumps, with things like exhausts and wheel arches being damaged."
Mr Colbert called in engineers from the council to inspect the bumps following the complaints.
"When the engineer saw them he didn't need to get his tape measure out to check the height, he knew straight away that they were the wrong ones," said Mr Colbert.
'Contractor's expense'
"The village of Lunt is also having the same problem.
"Questions now need to be asked of the council as to why no visual inspections were done."
A statement from Sefton Council, which authorised the work, said work to lower the humps was starting on Friday and expected to last two days.
It stressed the cost of the new work was being met by the contractors who carried out the work, and not from the public purse.