All sides in the Millennium Tower debacle appear to be nearing an agreement on a $100 million-plus fix to stop the 58-story high-rise from sinking further — but at least part of the building’s tilt will probably remain.

“We’re very encouraged by the recent progress that has been made,” said P.J. Johnston, spokesman for Millennium Partners, the luxury condominium’s developer. “We look forward to working with the homeowners and the city to get this all completed as soon as possible.”

Doug Elmets, spokesman for the homeowners association, cautioned that nothing has been submitted to the city yet for review, but that residents are “encouraged by the ongoing progress.”

The latest plan calls for drilling piles into bedrock from the sidewalk on the building’s southwest corner. The proposal would be less extensive and intrusive than the plan floated in April, which called for drilling as many as 300 micro-piles to bedrock through the building’s concrete foundation.

The idea was to stabilize one side of the 58-story structure, then let the other side continue to sink until the building straightened itself. That plan, however, probably would have cost upward of $350 million — as much as it cost to build the tower in the first place.

The new plan by Ronald Hamburger, the structural engineer for the developer, is expected to be considerably less expensive and faster, and without as significant a disruption to the residents.

“Hopefully, it will take out some of the tilt and stop the building from moving entirely,” said one source familiar with the plan, but who wasn’t authorized to speak for the record.

The tower has sunk 18 inches and tilted 14 inches to the west since it opened in April 2009.

The building sits on a 10-foot-thick mat foundation, held in place by 950 reinforced concrete piles sunk 60 to 90 feet deep into clay and mud. They do not, however, reach bedrock.

The repair job is expected to take several months to complete. The timeline for getting started, however, will probably hinge on how fast the parties can get approval of an environmental impact report and the necessary building permits.

We’re told the construction work will not require the closure of the 300 block of Mission Street, a major east-west artery routinely clogged with city buses and other vehicles. The work, however, probably will cause some traffic disruptions along Mission.

Hamburger’s analysis of the building last year, paid for by the developer, concluded it was safe enough to withstand an 8.0 earthquake. A three-member expert panel hired by the city subsequently reached the same conclusion — that the building is safe.

Millennium Partners has blamed the sinking on ground shifts brought on by the construction of the huge Transbay Transit Center, which is just across Fremont Street from the tower. The bus hub opened in August, only to be shut down six weeks later when cracks were discovered in a pair of girders over Fremont Street.

Taxpayers are already on the hook for up to $15.7 million in lawyer fees to help fend off claims by the Millennium developer and homeowners that construction of the transit center contributed to the sinking and tilting of the luxury high-rise.

In all, nine lawsuits have been filed in the Millennium case, with no fewer than 146 lawyers involved.

Late last week, San Francisco Superior Court Judge Curtis Karnow, who is presiding over most of the condo owner cases — including a major one against the Transbay Joint Powers Authority, which built the transit center — issued a notice that he is pushing back the first scheduled trial until October “to enable the parties to focus on (private) mediation and funding of a retrofit.”

Southern California attorney David Casselman, who is representing more than 250 of the building’s 400 condo owners in their suit against the authority, didn’t rule out a courtroom showdown if the deal for the proposed fix unravels.

“We are deeply involved in the litigation process and looking forward to trial,” Casselman said, “but if it is possible to resolve the case, we welcome the opportunity.”

On the money: Fresh from voter approval of an $18 million-a-year parcel tax extension to help keep its doors open, City College trustees are now looking to go back to voters next November with a whopping $800 million facilities bond.

“With some of our buildings, it’s questionable if they could withstand an earthquake,” college Trustee John Rizzo said. “You would be appalled at the condition of some of the buildings we are trying to teach in — they are well beyond their designed age.”

And it looks like the voters agree.

A Tulchin Research poll the district commissioned found 77 percent voter support for a new facilities bond — well above the 55 percent support required — with the respondents not appearing to care whether the ask was for $450 million or $800 million.

So the district is preparing to go for the full load.

Still, competition for votes could be steep, as there are likely to be competing measures on next year’s ballot seeking money. District officials expect to descend on City Hall this week to gauge the temperature of Mayor London Breed and the Board of Supervisors.

San Francisco Chronicle columnists Phillip Matier and Andrew Ross appear Sundays, Mondays and Wednesdays. Matier can be seen on the KPIX-TV morning and evening news. He can also be heard on KCBS radio Monday through Friday at 7:50 a.m. and 5:50 p.m. Got a tip? Call 415-777-8815, or email matierandross@sfchronicle.com. Twitter: @matierandross