Bloody Brakes

Jun 12, 1999

RAY: Hi, we're back. You're listening to Car Talk with us, Click and Clack, the Tappet Brothers, and we're here to discuss cars, car repair and the new Puzzler.

TOM: Yes, and...

RAY: When I said this was a "new, old Puzzler," you're going to remember it.

TOM: New, old stock. Yeah.

RAY: This was sent by a guy named John Tomasetti from somewhere out there, some dot com place, dot com. Anyway, he says this is a real-life situation, actually happened to me, etc., etc. He has a 1982 Jeep CJ7, and it had sticky front-brake calipers. So, he decided that he was going to rebuild them himself. "So," he said, "I bought the rebuilding kits for both front wheels and proceeded to rebuild the calipers myself. The rebuilding kits included all the necessary o-rings and dust boots, as well as new steel pistons to complete the job. I proceeded to rebuild both of these front calipers, feeling good that I had no spare parts left over. I was satisfied that I did the rebuild job correctly, and, in fact, that my work was flawless. However," he goes on, "when I finished the job, I couldn't seem to bleed the brakes properly. The pedal went to the floor as if there were air trapped in the system. I must have bled a gallon of brake fluid through the system to no avail, but there were no leaks. Finally, I took the Jeep to a shop, and, using their professional equipment, they bled them--to no avail."

TOM: Wow!

RAY: Finally they say, "You need a new master cylinder." They, what? Replaced the master cylinder three times to no avail. They checked the lines, they checked the rear brakes--everything in perfect condition. They gave up.

TOM: Wow! Now what? I'm awed!

RAY: After five days, three more master cylinders, and many more gallons of brake fluid, he takes the thing to the Jeep dealer. They bleed the brakes, they put in master cylinders, they do all this and, finally, someone figures it out, and it cost no money to get it fixed.

TOM: Yeah!

RAY: So, what did they do? What did this one brilliant guy notice...

TOM: Yeah, as he stood there, saying, "Hey!"

RAY: "Hey!"

TOM: "Hey, jerk!" Yeah.


RAY: What had happened was the following:

TOM: Boy, this is good.

RAY: John rebuilt both calipers. In other words, he took them--I can only imagine--put them on his dining room table, took them all apart, installed the new kits that he had--flawlessly, I might add--and reinstalled them. But in doing so, he put the left one on the right and the right one on the left, and by making that mistake, the bleeder--that is, the little valve you open to let air escape from the system--was at the bottom of each caliper, because he had flipped them around, and not at the top where, what?

TOM: The air goes.

RAY: The air is. If you take a liquid that has air in it too, and you flip it upside down, no matter what you do, the air always goes to the top.

TOM: You can try this out with a bottle of orange soda.

RAY: You can.

TOM: Which we do every week here.

RAY: And no matter how much bleeding you do, there is so much air, which is compressible, trapped in the system, that you cannot get a brake pedal no matter how many master cylinders you put in. What this fellow noticed is the same thing that we noticed with poor Jim Pritchard, after he bought 18 gallons of brake fluid from us and replaced the master cylinder four or five times, that the calipers needed to be put in the right place and then the thing bled just like that.

TOM: Bingo!

RAY: Who's our winner this week?

TOM: The winners. It says David and Kay Mowry, husband and wife, mother and son, daughter and father--I don't know. But David and Kay Mowry from Riverside, California.

Get the Car Talk Newsletter