A family that runs a small chain of Hasidic clothing shops is in turmoil because one of its founders has launched a ​competing ​line of fur hats, black coats and trousers.

Making matters worse, the owners of Glauber’s Quality Clothing say in their $2 million Brooklyn federal lawsuit, their rogue brother set up shop less than a mile away.

​Glauber’s, founded by a group of Brooklyn siblings in 1985, contends that the brother, who isn’t identified, ripped off their trademark and should be forced to stop using the name immediately.

They claim that rival Glauber’s Traditional Clothing​ is selling ­Hasidic items from yarmulkes to long black coats and fur hats in an effort to cash in on the sterling reputation of the original company.

“Our client has good reason to be concerned that the owners and driving force behind this business about to be launched is none other than their former business partner (and brother),” reads a cease-and-desist letter submitted​ this month.

“There is absolutely no reason or justification for your company to adopt the Glauber name, in competition with its former partner,” the letter states.

Rather than abandon the moniker, the ​separatist Glauber instead opened a ​new ​emporium in ­upstate Monroe, less than a mile from one of their stores, court ­papers state.

The upstart’s attorney, Michael Steinmetz, called the lawsuit an 11th-hour “ambush” and asked Judge Pamela Chen not to force an immediate restriction on the use of the family name.

“Plaintiff’s shameful tactic should not be rewarded,” his court filing states, noting that a ruling “in the middle of its grand opening” would be “devastating.”

Steinmetz argued that the original Glaubers officially sought to trademark the title only in 2012 and that it’s an “inherently weak mark.”

In its suit, the original company argues that its products were “met with popular approval as a result of plaintiff’s extensive marketing, promotion, advertising and sale of its products,” according to court papers.

“Garments offered for sale by defendant and intended for sale to the Chassidic men’s community bear a label which not only contains our trademark, but contains a logo intended to emulate the logo of the plaintiff,” the suit states, ­using the traditional spelling.

Steinmetz declined to comment on the case.

The attorney for the plaintiff, Avrom Vann, also declined to comment.