(Adds close of U.S. markets)
* China data, investor caution before Brexit vote, hit markets
* China GDP grows 6.0% in third quarter, near three-decade low
* Dollar posts worst week in almost four months ahead of vote
* Euro at near two-month high, sterling at five-month high
By Herbert Lash
NEW YORK, Oct 18 (Reuters) - The dollar posted its worst week in almost four months on Friday, pummelled by sterling and euro rallies driven by a deal on Britain's departure from the European Union, while China's weakest growth in nearly three decades weighed on equities.
The dollar crept lower against the euro as the common currency enjoyed a lift from hopes a Brexit deal could improve the odds of the euro zone avoiding a recession.
Dismal manufacturing data and worries the U.S.-China trade war could slow euro zone economies even further have rattled the euro this year, while fears of a disorderly Brexit had slammed sterling until a week ago.
"We can easily tell what's driving the euro, and that's a potential Brexit deal. We're going to find out this weekend whether this is going to turn into a realty or whether it's a pipe-dream," said Paul Mendelsohn, chief investment strategist at Windham Financial Services in Charlotte, Vermont.
The euro rose 0.36% to an almost two-month high of $1.1162. Sterling climbed 0.42% to a fresh five-month high of $1.2942.
British Prime Minister Boris Johnson confounded his opponents on Thursday by clinching a new deal with the EU, even though the bloc had promised it would never reopen a treaty agreed on last year.
Parliament will vote Saturday on a deal that could lead shares in British-oriented businesses, such as housebuilders and retailers, to rocket to record highs if approved. Investors also predict the pound could rally about 5%.
Michael Hewson, chief market analyst at CMC Markets in London, said however members of parliament cast their vote, the Brexit saga is unlikely to be over.
"If MPs do hold their noses and vote for the deal, at least we can move on to phase 2 which is negotiating the new relationship over the next 14-month transition period," he said.
Gloomy earnings reports from French carmaker Renault and food group Danone drove European shares lower while negative headlines about Johnson & Johnson and Boeing on Wall Street offset generally positive U.S. corporate earnings.
MSCI's gauge of stocks across the globe shed 0.24% while the FTSEurofirst 300 index of leading European shares closed down 0.38%.
Bleak Chinese economic data also soured risk appetite, with the Shanghai Shenzhen index falling 1.2%.
Asian stocks stumbled after China's third-quarter growth slowed more than expected to its weakest pace in almost three decades as the bruising U.S. trade war hit factory output. Gross domestic product (GDP) rose 6.0% year-on-year.
Wall Street also edged lower on worries about the global economy following China's GDP data and J&J after it moved to recall a batch of baby powder.
J&J shares fell 6.2% while Boeing slid 6.79% after it turned over messages from 2016 between two employees that suggest the airplane maker may have misled U.S. aviation officials about a key safety system on the grounded 737 MAX.
Robust earnings from Coca-Cola Co and Schlumberger NV , among others, helped mitigate the losses. Coke rose 1.84% and Schlumberger added 1.32%.
The Dow Jones Industrial Average fell 255.68 points, or 0.95%, to 26,770.2. The S&P 500 lost 11.75 points, or 0.39%, to 2,986.2 and the Nasdaq Composite dropped 67.31 points, or 0.83%, to 8,089.54.
Euro zone bond yields rose a day before the Brexit vote. Yields have generally pushed higher since Irish and British leaders said a week ago they saw a path to a deal, boosting risk appetite and eroding demand for safe-haven assets such as bonds.
Germany's 10-year Bund yield was at -0.39%, after touching its highest since late July on Thursday.
U.S. Treasury yields fell as investors awaited Saturday's Brexit vote, with the benchmark 10-year U.S. Treasury note up 1/32 in price to push yields down to 1.7501%.
Oil prices edged lower as concerns about China's economy outweighed bullish signals from its refining sector.
Benchmark Brent crude oil futures settled down 49 cents to $59.42 a barrel. U.S. West Texas Intermediate (WTI) crude futures fell 15 cents to settle at $53.78 a barrel.
Gold steadied, helped by a weaker dollar. U.S. gold futures settled 0.3% lower at $1,494.10 an ounce.
Reporting by Herbert Lash Editing by Chris Reese and Tom Brown