Crews trying to replace a frayed cable on the Stillwater Lift Bridge have run into a problem: They can't get a replacement.

MnDOT might have to order parts from elsewhere, and once the department gets them, it could take a week to install the cable, spokesman Kent Barnard said Monday.

Problems started Sunday night.

The damage to a cable on the northwest end of the 80-year-old structure was discovered after a bridge operator heard a loud noise as the bridge was being lowered about 8 p.m.

That is when lift operations were ceased, said Duane Green, maintenance operations engineer of structures for the Minnesota Department of Transportation.

It was not immediately known why three of the six strands that make up the ⅞-inch wire frayed. They were fine last month when MnDOT greased them, Green said.

Green said MnDOT does not have the specialized wire on hand and is checking with area suppliers. As to when the fix will be made, Green said: "It's anybody's guess. We hope we can find things. July 4 is coming up."

Until the bridge is fixed, it will remain in the down position. That means vehicles and pedestrians can to get across, but some river traffic is unable to get through.

Dick Johnson, owner of the Stillwater Yacht Club, said Mondays are normally slower days on the river and that traffic was very light. "I don't see a boat and I am right by the bridge," he said.

Green said smaller boats that can safely pass under the bridge can get through, but high water levels may prevent some from passing.

Tara Graham, a spokeswoman for the St. Croix Boat & Packet Co., said all tour boat trips will go on as scheduled, but none will be able to travel north of the bridge.

Crews arrived early Monday to start repairs and inspect the bridge to make sure there was no other damage.

The bridge, which connects downtown Stillwater with western Wisconsin, carries about 18,000 vehicles each day.

The bridge was out of commission a month ago when crews replaced a gear box.

The bridge was also shut down for several months last year for major repairs to electrical and mechanical components.

The landmark is being replaced by a new St. Croix River crossing just south of Stillwater. Construction of the new Hwy. 36 bridge over the river began this year and is expected to be complete in 2016.

At that time, the lift bridge will be off limits to vehicles and accessible only to bicyclists and pedestrians.