When the horror stories of $1,100 stool caps and $400 hammers began to surface midway through President Reagan's first term, Congress swiftly responded.

And responded. And responded.

Reform legislation in 1983 was followed by the Competition in Contracting Act of 1984, the Defense Procurement Reform Act of 1984, the Small Business and Federal Procurement Competition Enhancement Act of 1984 and other reforms in annual defense authorization and appropriation bills. Congress is expected to approve dozens more this year.

One result: A spare part the Air Force used to be able to stock in 58 days now takes 159 days to go from order form to shelf.

"It's all good stuff," said one procurement officer, "but it all slows us down."

The spare parts experience illustrates one of the basic rules of Pentagon reform: almost every change inflates the bureaucracy.

In 1964, for example, Defense Secretary Robert S. McNamara decided it did not make sense for each service to hire its own contract officers. So was born one of McNamara's many consolidated agencies, the Defense Contract Administration Service.

When the Grace commission examined this reform two decades later, it found 17,000 contract administrators working for the new agency, 3,000 fewer than before consolidation. But it also found that the Army, Navy and Air Force still employed more than 10,000 contract administrators of their own.

Pentagon officials acknowledge that many recent congressional reforms correct past stupidities in buying habits. The reforms require the Pentagon to seek warranties, justify cost increases, and encourage alternate producers for sole-source purchases. But almost every reform also saps responsibility from procurement officials; more and more bureaucrats must sign off on each decision, no matter how small.

As a result, the backlog of procurement requests for Air Force spare parts jumped from 14,000 in the summer of 1983 to 27,000 a year later. Four-fifths of the F15 engines the Air Force keeps in reserve are unusable for lack of key components.

And the Air Force now must forecast its future spare-parts needs nine months in advance, increasing the odds of costly miscalculation.

"Now that we're cleaning up this end of the operation, we're starting to mess up the other end," one officer said resignedly. "That could be the next thing everybody wants to look at."