Dudley, which lends exclusively through intermediaries, launched its service in September last year.
The building society stopped giving advice on its own products due to the looming Mortgage Market Review, instead only accepting business from fully regulated intermediary sources.
Brilliant Solutions, which is part of the Brilliant Group, was founded in 1994.
Gordon Rae, intermediary relationship manager at the Dudley Building Society, said: “We have been delighted with the business we have received so far from our existing partners and now we have bedded in our systems, it is time to expand our panel and increase our market share.
“Brilliant Solutions has a deserved reputation as a supporter of the intermediary market and I am sure their introducers will help us towards our new business goals.”
The initial firm panel was made up of seven partner firms.
Matthew Arena, managing director of Brilliant Group, added: “The building society sector has proved time and again its commitment to common sense lending and support of the intermediary community.
“The Dudley Building Society’s stance of exclusively dealing with the broker market is a statement of how much they believe in the primacy of independent advice and we are delighted to be the newest member of their lending partner panel.”