SAN FRANCISCO (CBS SF) — The Golden Gate Bridge is in need of some love and its corrosion in causing concerns.

While the San Francisco-Oakland Bay Bridge regularly gets a paint job to prevent rust, the Golden Gate Bridge doesn’t receive the same attention.

The Caltrans bridge painters hunkered down on a wooden platform, suspended mid-air are painting and re-painting the western span of the San Francisco-Oakland Bay Bridge.

It is a process that has been on-going for over nine decades. And in a spot on the bridge about two miles from San Francisco, painters have been working for two months.

The process is a big undertaking. First the painters have to grind down the steel. Then they smooth it out. After that they apply two coats of primer, and then two coats of paint. The job must be done in a thorough, careful manner, because the painters know they might not be back at this location again for 20 years.

“If we don’t paint the bridge, then the bridge rusts,” explained Conrad Melendez, a structural steel bridge painter and longtime Caltrans employee.

Just across the Bay, Golden Gate Bridge painters do similar work. But the Golden Gate Bridge’s main cable has not been painted in its entirety since the mid-1930s, only spot painted.

When viewed from the air by helicopter or from the ground, virtually the entire length of the cable housing appears to show wear and tear.

Golden Gate Bridge Manager Denis Mulligan explained that the Bridge District has different time frames to do work on different components of the bridge, and says that the District has based those time frames on what kinds of repairs and upkeep might be needed.

Mulligan also told KPIX 5 that while the outside cable casing may look bad, the 27,000 individual steel strands inside the cable casing have remained pristine.

But the question persists: Could the condition of the strands change if moisture were to seep inside of the main cable casing, or if the casing were to corrode away from rust? It is a possible threat that the Bridge District has known about for decades.

In fact, back in 1969, the District hired an outside consultant engineering firm to walk the bridge. The firm issued a report that recommended the main cable be painted in its entirety as soon as possible.

Despite the recommendation, it never happened.

The District started the project about five years ago, but then stopped the painting. Engineers announced that the hand rails along the main cable needed to be replaced, for the safety of the bridge painting crews.

“This was a big deal,” explained Mulligan. “Yeah, my hunch is that the engineering evaluation had not been done. At that time it was not known that the hand ropes were approaching the end of their useful service life.”

Even Golden Gate Bridge Board of Directors member Dietrich Stroeh has had some concerns about the cable, and the south tower. Stroeh has talked to staff about getting the project going again.

But Stroeh said that another section of the bridge needed to be treated for rust.

“We found in exposing some of the sub structures that the bracing underneath which is like crisscrossed, behind the riveted piece on there,” explained Stroeh. “It was all rusty.”

Then there’s the money for the painting of the cable in its entirety. The Bridge District had set aside tens of millions of dollars to paint the bridge back in 2011. But Stroeh said it was spent on other projects.

KPIX 5 was able to obtain a copy of an internal budget document which shows that the Bridge District hopes to start funding a cable painting project by 2018, with the project possibly completed by 2022.

That would be 85 years since the Golden Gate Bridge opened.