Investors also cut long dollar positions amid tight liquidity.
Stocks weakened, with Steinhoff topping the decliners after its chairman resigned late on Thursday.
At 5pm, the rand bid at R13.2719 to the dollar, 18.17c stronger than at the same time on Thursday.
Courts ruled that senior officials in two provinces seen as supporting ANC presidential candidate Nkosazana Dlamini Zuma had been illegally elected and could not attend the conference.
“Markets are definitely viewing that court ruling as positive for the rand, more especially positive for the (Deputy President Cyril) Ramaphosa campaign,” said senior forex dealer at Standard Bank, Oliver Alwar.
The race was mainly between Ramaphosa, generally favoured by financial markets, and Dlamini Zuma.
It was seen as too close to call.
“I think markets are discounting far too much of a Cyril victory. Its not cut in stone. Things could change very easily over the weekend,” Alwar said.
Ramaphosa, a billionaire businessman, was seen as the most business-friendly candidate, compared with Dlamini Zuma supported by President Jacob Zuma, her former husband, and the five other contenders.
The woes of Steinhoff continued to weigh on the bourse after South African tycoon Christo Wiese resigned on Thursday as chairman of the retail group, the latest setback for the firm in the throes of an accounting scandal.
“Everybody is waiting for them to publish their results to see how deep the rot is. We’re not getting any kind of feed back, any kind of news feed from the company itself which is what is frustrating everybody,” said BP Bernstein trader, Vasili Girasis.
Steinhoff retreated 9.98percent to end the session at R8.03.
PSG Group, in which Steinhoff owns about 25percent, weakened 2.64percent to R243.41 after Steinhoff said it has sold a 9.5percent stake in PSG for R4.7billion.
The benchmark JSE Top40 index shed 1.06percent to 50953.23 points, and the broader all share index weakened 0.75percent to 57412.76 points.