A Genuine Automotive Puzzler

The Puzzler

RAY: And it was not a pine tree air freshener.

TOM: I have no idea.

RAY: I was going to give an additional hint. I should have, perhaps. That he could have said, yes, I bought two of them.

TOM: Oh! I got it. Floor mats.

RAY: I can always count on my brother for thinking outside the box. What he bought was a new tire, and when they installed the tire on the car, they didn't balance it correctly, or didn't balance it, perhaps, at all. And as the car is going down the road and the thing is shaking, it is setting up a sympathetic vibration in the disc rotor, which is moving the caliper piston away from the disc, so that when you step on the brake that first time, the pedal will travel almost to the floor. We've seen this happen with cars whose wheel bearings are loose.

TOM: I actually like this answer.

RAY: And when you step on it that first time, that caliper has to move.

TOM: Has to move much further away.

RAY: Because that caliper piston is now not touching the brake pad. And then finally, when it does make contact, the second pump --

TOM: Bingo!!

RAY: -- is OK. And of course, you drive along for 10 more minutes, the vibration occurs. And he said it was undetectable, virtually, because the car had so many other vibrations and moans and groans or whatever, he never noticed it. And the hint was that it was a Datsun B210.

TOM: No, I like that answer!

RAY: Well, I'm glad!

TOM: That's great!

RAY: Anyway, who's our winner, Tommy?

TOM: I don't know. I gotta look on this little piece of paper. Ah! Erica Coffin from Austin, Texas.

[ Car Talk Puzzler ]

Support for Car Talk is provided by:

Donate Your Car,
Support Your NPR Station

...and get a tax break!

Get Started

Find a Mechanic

Promo tile

Rocket Fuel