Q. I was working on my father-in-law's old beater and rounded off every single one of the brake-hose fittings with an open-end wrench and vise grips. I had to hacksaw the steel lines off at the fitting and use a six-point socket to get them to budge.
Now my father-in-law thinks I'm an idiot.
Do they make sockets with a slice cut out so that you can loosen a stubborn fitting like this without rounding it off?
A. No, but they do make flare-nut wrenches.
You've run aground on a common problem encountered while working on older cars: The brake line fittings are corroded. They won't budge if you turn them with an open-end wrench, which contacts the fitting only in two places. Worse yet, if some of that fitting's metal has rusted and flaked off, it is now undersized, and you'll only round off the fitting trying to get enough torque to turn it.
A flare-nut wrench can help. It was actually developed to turn the soft brass nuts used in flare fittings without collapsing them.
Flare-nut wrenches contact the hex at all six flats, tripling the torque you can apply before something fails and you bust a knuckle. I use these wrenches on almost any nut, bolt, or fitting that seems to need an excessive amount of muscle to remove.
I prefer them even to box wrenches, because their six points of contact touch more of the meat of the nut or bolt than a 12-point box end. In addition, you can get this wrench over a stud that's protruding and awkward to access with a box wrench or even a deep socket.
Q. Many years ago you discussed a transmission that was belt-driven. It was going to replace all existing transmissions because it was simple and had many fewer moving parts.
Can you tell me what happened to that transmission? I owned a Riva motorcycle and it had this sort of transmission.
A. You're probably talking about the belt-driven constant-velocity transmission that was used by DAF Trucks in Europe.
It is now in use on virtually all snowmobiles. A number of car manufacturers - including Audi,
Q. Can battery sulfation be completely removed?
A. No, but there are some battery chargers on the market that claim to be able to largely remove it by adding a high-frequency waveform to the DC current while the battery is charging. The claim is that the high frequency reduces the size of the sulfate crystals and will remove them.
Hey, I was skeptical too. But I've doubled the lives of the batteries on my bikes, which spend a great deal of time on chargers.
Q. I have a 1997 Dodge Dakota. The dash-cluster light has gone out. I have checked the fuses, and they seem to be OK.
How many lamps are behind the cluster? Is it a big task to replace them?
A. According to my shop manual, there is only one bulb. And the replacement must be pretty straightforward, because there is no procedure for it, and it is supposed to take only 20 minutes.
Q. I recently bought a 2006 Nissan Maxima. The ride is rough, so I would like to replace the tires.
I have low-profile, 18-inch tires. What type of tires should I buy for a softer ride?
A. Buy new rims, ones smaller in diameter. I would look for salvage rims.
Then buy new tires to fit the rims, but with a higher profile and the same rolling radius. Mount the tires on the rims, and the rims on the car.
Or maybe you can trade with someone who wants low-profile tires.
Mike Allen is a senior editor for Popular Mechanics magazine. Questions should be sent via e-mail to driveit@nytimes.com.
