* 30-year U.S. Treasury yield falls to lowest in at least 60 yrs
* June ISM index at 53.2 vs estimate of 51.4
* U.S. exchanges closed on Monday for Independence Day
* Indexes up: Dow 0.2 pct, S&P 0.25 pct, Nasdaq 0.52 pct (Updates to early afternoon)
By Yashaswini Swamynathan
July 1 (Reuters) - U.S. stocks extended their gains and were up for the fourth straight day on Friday as strong manufacturing data boosted prospects for an improvement in the economy.
The S&P 500 is on track for its best weekly gains since October, having recovered sharply from a bruising selloff after Britain voted to quit the European Union.
Investors are now pinning their hopes on central banks easing monetary policy to support global growth.
Data from the Institute for Supply Management (ISM) showed its index of national factory activity rose to 53.2, topping expectations of 51.4, according to a Reuters poll.
Adding to the upbeat mood, the U.S. auto industry was on track to record its best June sales in more than a decade.
"It's been a wild ride, but positive economic momentum in the United States has and continues to be a ray of sunshine," said Daniel Kern, chief investment strategist of TFC Financial Management in Boston.
However, yields on safe-haven government bonds slipped around the world, showing investors were uncertain about the state of the global economy, particularly after the Brexit vote.
The yield on 30-year U.S. Treasury hit its lowest since the 1950s.
"The longer-term problems we have in the United States haven't gone away and that's what's causing investors to be a bit jumpy," Kern said.
U.S. stock exchanges will be closed on Monday for the Independence Day holiday.
At 12:18 a.m. ET (1541 GMT), the Dow Jones Industrial Average was up 35.88 points, or 0.2 percent, at 17,965.87, the S&P 500 was up 5.32 points, or 0.25 percent, at 2,104.18 and the Nasdaq Composite was up 25.02 points, or 0.52 percent, at 4,867.69.
Seven of the 10 major S&P indexes were higher, with the consumer discretionary sector's 1.17 percent rise leading the gainers.
Harley-Davidson's shares were up 12.7 percent at $51.05 - their biggest intraday gain in more than seven years - on market chatter that motorcycle company might be a takeover target. The stock was the top percentage gainer on the S&P.
Micron Technology fell 10 percent to $12.38 after the chipmaker reported disappointing quarterly sales and forecast and said it would cut jobs.
Netflix rose 5.2 percent to $96.28 after Canaccord Genuity initiated coverage with a "buy" rating.
Advancing issues outnumbered decliners on the NYSE by 2,018 to 951. On the Nasdaq, 1,750 issues rose and 965 fell.
The S&P 500 index showed 88 new 52-week highs and no new lows, while the Nasdaq recorded 83 new highs and nine new lows. (Reporting by Yashaswini Swamynathan in Bengaluru; Editing by Saumyadeb Chakrabarty)