Brash little Lanny Wadkins and big, truculent Tom Weiskopf sank spectacular shots on the 18th green today to share a two-shot lead after the second round of the World Series of Golf.

Wadkins, the current PGA champion who sometimes seems to carry a chip as big as a driver on his shoulder, finished a brilliant 36 30-66 round by holing a 70-foot trap shot at the final hole.

Wadkins not only sank the shot, he even joked he would to his partner, Jerry McGee, as they walked up to the green.

Weiskopf, who streaked up and down all day, put a stop to a rash of four bgeys in five holes by finishing birdie-birdie. His final act of the 31 31-68 round was a 70-foot putt at 18.

Mark Hayes carded a 69 for third spot at 137. First-roound leaders Ray Floyd and Hale Irwin both had 71s to come in at 138, while Graham Marsh. McGee and Gary Player, at 139, were the only others under par.

Jack Nicklaus eagled the second hole to go three under par and seemed to be in the thick of the chase, But he came unglued and shot himself out of contention with a triple bogey at the sixth hole.

Soon after Nicklaus came into the press tent to expain how he had 1) sliced into the trap, 2) played from one trap to another deliberately, 3) bladed a ball over the green and 4) stubbed a chip - all on the same hole - he got another jolt.

A can of soda exploded, drenching him. With his chances for a $100,000 victory and the money-winning title virtually down the drain. Nicklaus looked at the offending soda and said. "I even double-bogeyed the interview."

Wadkins and Weiskopf both played spectaculary erratic rounds.

Wadkins bogeyed the last three holes of the front nine after getting into disagreements with his caddie over club selection on all three approach shots.

"I just told myself. 'The hell with it. Let's get back under par.'" said Wadkins, who survived to two-year slump after gall bladder surgery at the end of 1974.

Wadkins fired birdies at 10, 12 and 13 - the last on a 50-foot shot that he was just trying to get close.

As Wadkins and McGee walked up the last fairway, McGee said. "Get it close out of the trap, Lanny, and you may even be tied for the lead."

"Heck," answered Wadkins. "I'm gonna hole it. I haven't blasted in for a long time. I'm due."

"I was just givingJerry a hard time," explained Wadkins, but when I saw I had a good lie and the green was soft around the hole. I tired to knock it right at the flag."

Wadkins always has torn up the tough Firestone course. He wons the course record of 63 and once was 17 under par for three wounds in winning one of his two CBS Golf Classiscs on this 7,130-yard layout.

"Maybe I play because I always attack," said Wadkins, who shoots for the pins.

Faced with the difficult sand shot, Nicklaus decided on a cautious strategy. Instead of risking double bogey, he would play from on trap to another, then count on getting up and down with an easy sand shot.

The plan might have worked, except Nicklaus cracked the "easy" sand shot over the green.. Nicklaus "saved" his triple bogey with a four-foot putt.

At the next hole Nicklaus hooked his drive, hooked his approach shot into a trap adn took a bogey. his quest for back-to-back victories in the World Series seemed all but dead.

Wadkins hardly could have appeared more confident after his closing 30, one off the back-nine record, "the key here is to hit it straight, more than hit it far," he said, pointing out that his notions about attacking Firestones must not be all bad.

Weiskoph had a perfect opportunity to blow up as he so often has. After eagling the par-five second hole with a 10-foot putt following a drive and a three-iron. Weiskopf got two more birdies to got seven under and lead the field by three shots.

After his 31 on the front. Weiskopf did not expect to do as well on the second nine. "The par-fours into the wind on the back were going to be tough. You have to accept some bogies on this course. You have to hit tha ball so hard time after time that it messes up your tempo."

But Weiskopf never guessed he would bogey 12, 13, 15 and 16.

"I was behind trees, I plugged a ball in a trap and finally at 16 I drove into a hazzard," said Weiskopf. "I just told myself. "If you can hang on, you'll be right near the top."

At 17, Weiskopf, usually such a delicately balanced machine, turned the collapse around with a downwind birdie from 18 feet. But his 70-footer at 18 was pure gravy. "A good start and a good finish," quipped Weiskopf, who started and finished birdie-birdie on Friday. "That seems to be my only pattern."

Nicklaus was the day's main victim. "I think Jack's really exhausted" Lee Trevino said before the round. "His legs are tired adn his hands are taking over and he's hooking everything left."

That's what caused the crash today. Nicklaus hooked his drive at the sixth into trees, then tried to play a slice to the green. "It didn't slice," he reported, "and it buried in the front trap."

Shot 63, 63 64, and two 66s here." he said, "I'm not an excellent putter, but here, because the greens are fast, I don't worry about gettin the ball up the hole, I just concentrate on line."

Today that was enough. That and a fairly accurate line on one last bunker blast.