JOHANNESBURG, August 1 (Reuters) - The South African rand was on the backfoot in early trade on Friday, as investors weighed the prospect of higher tariffs on exports to the United States after the country failed to clinch a trade agreement before Washington's deadline.

At 0708 GMT the rand traded at 18.23 against the dollar ZAR=D3, near its previous close and at its lowest level since May 14.

In an executive order on Thursday, U.S. President Donald Trump modified tariff rates for some countries but South Africa's figure was kept at 30%, as he seeks to reshape global trade on more favourable terms for the United States.

The order said the higher duty rates would take effect in seven days.

Domestic investors will also look to the release of a purchasing managers' index (PMI) survey for the manufacturing sector at 0900 GMT and vehicle sales data ZAVEHA=ECI due around 1200 GMT for clues to the health of Africa's most industrialised economy.

South Africa's benchmark 2035 government bond ZAR2035= was stronger in early deals, as the yield fell 3 basis points to 9.6%.

The country's government borrowing costs dropped to their lowest in five years after the Reserve Bank said on Thursday it would lower its inflation goal, despite the finance minister not yet having signed off on a formal change of target.

(Reporting by Sfundo Parakozov; Editing by Clarence Fernandez)

((Sfundo.Parakozov@thomsonreuters.com))