WHEN MATT Kraybill approached his Dodge Ram truck in the Wachovia Center parking lot after a recent concert, he realized he was in trouble. He had two flat tires.

Closer inspection revealed that someone had pulled out the valve stems; he suspected it was the limo driver he'd had words with before the concert.

How was he supposed to get home? Wachovia security and Philadelphia police seemed indifferent. Cars exiting the lot passed him by.

There was nothing to do but wait the long hours it would take for roadside assistance to come and tow his truck. He felt lonely and helpless.

What a way to spend his 31st birthday.

Then a car stopped. And the driver got out.

It's about here in the telling of the story that people suspect Matt Kraybill got mugged, robbed, or worse, that some thug took advantage of his vulnerable situation to victimize him.

Nothing could be further from the truth. Because the man who got out was Michael Olshefski.

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Although everyone in Olshefski's car was feeling uncomfortable - the bathroom lines after the concert were too long to wait - they agreed he should stop to help the guy with the flat tires.

They knew he was going to do it anyway. Even though Olshefski, 47, is a Camden juvenile probation officer who sees the sordid side of life, he remains a sensitive and generous soul.

"That's just the way he is," said wife Elida, who works at the U.S. Attorney's Office.

Olshefski offered Kraybill his tire pump. But the pump was useless without the valve stems.

Olshefski got back in his truck and drove away.

"I felt bad that I couldn't help them," Olshefski said of Kraybill, his wife and parents. "They were such nice people."

But while he was waiting in line to exit the parking lot, Olshefski got a brainstorm.

"I thought, 'wait a minute. He has the same truck I do. I have a spare tire. He has a spare tire.'"

With the permission of the family members who were with him, Olshefski turned around, drove back and offered Kraybill the spare.

Kraybill was astonished.

He protested that it wasn't safe for Olshefski to drive home without a spare. Olshefski said he lived nearby in Oaklyn, N.J.

And that's how Matt Kraybill, a sixth-grade social studies teacher, wound up getting home that night

* * *

The next day, Kraybill returned the tire to Olshefski's house and tried to palm him $100. He wouldn't take it.

"No way was I going to take any money," Olshefski said.

When Kraybill insisted he pay him back somehow, Olshefski said "just pass it on."

Neither man had ever seen the movie, "Pay It Forward," with that very same theme.

"The whole way home, I couldn't stop thinking about everything that had occurred," Kraybill said.

And on Monday, the first thing he did was tell his students at Arthur Rann Elementary School in Galloway, Atlantic County, N.J., what Mike Olshefski had done for him- and what they could do for others.

* * *

Olshefski didn't give the incident another thought until he and his wife came home from work one night last week and found a packet of letters from Kraybill's students

The Olshefskis stood at the door with their coats on - their two dogs pacing, waiting to be let out - reading the letters, laughing and crying.

"After hearing the story, I think you are a great, nice person who puts other people's needs, even strangers, before their own. I hope that their are more people in the world like you and I am going to try to be one of them," Tommy wrote.

"When I listened to the story, I felt touched. I never in my 11 years heard a story like that before," wrote Maressa .

Emily wrote about her own experience with kindness, when her house burned down and her classmates gave her toys and stuffed animals:

"These things and you helping Mr. Kraybill has helped me figure out what I'm going to do when someone has a problem. Thanks for showing me how to do the right thing," she wrote.

"Thank you for helping out Mr. Kraybill (even though he is a Giants fan)," Evan wrote.

Olshefski was overwhelmed.

"What better way to 'send it on' than through kids in a learning lesson like that. It's pretty awesome."

Kraybill wrote him a letter, too. "I do consider myself to be a good person," he wrote.

"But I openly admit that I do not know if I would have gone to the extent to help someone in the manner that you helped me. That is no longer true.

"You have become a role model, even a hero, for me and I am confident that I will never place a limit to what I can do to help someone. My students have also learned an important life lesson which they are already applying to their lives."

To which I can only add:

Pass it on. *

E-mail porterj@phillynews.com or call 215-854-5850. For recent columns: