By
induction1, May 5, 2004
i thought i saw this somewhere here, but couldn't find it again; should one "bed" new brakes on a new corolla even if they're not perfomance brakes, and is this ok for drum brakes too? also, talk to me about changing drum brakes to disc. why do many cars have both drum and disc? doesn't make sense to me. by the way, in what manner should one break in a new engine? anything else helps.
thanks
Most OEM vendors recommend easy driving for 400 to 500 miles without heavy braking to bed in the brakes. Most performance pads need several moderate stops from increasingly higher speeds with enough time for cooling to bed in. Same applies to drum brakes shoes - just easy normal driving for 400 to 500 miles without heavy braking and you should be fine.
Why do so many cars come with disc/drum brakes - actually more and more cars are coming with discs all around - but for the most part, it is cost and performance driven. Most people do not drive their cars in ways that warrant discs all around. Most cases - drums do more than an adequate job of braking - look at semis - they all use drum brakes.
Changing from drum to disc can either easy or hard - depends on what was available for that particular model. Most of the time - it involves replacing the hubs in the back with appropriate spindles, mounting brackets, and hardware - then having to replace the master cylinder, proportioning valve, ABS hardware if equipped, and some more. They do have kits available - but they are not cheap - some start at around $1500 and go up.
Engine break-in period depends - some owner's manual do not recommend any break-in time. Some recommend varing the speed and RPMs for the first 500 miles or so. Just check out the owner's manual. If it was an engine swap - it would be a good idea to run an easy 500 or so miles, then change the oil and filter and run it for another 1000 - checking for any problems.
Good Luck.
The link I posted in the thread discussing warped rotors talks about how to break in you pads. It's pretty much the same as Fishexpo recommends.
One primary reason that many cars have rear drums: It has to do with the way they work. Disc brakes give you proportional braking, whereas drum brakes multiply the brake force. In other words, if you press twice as hard on drum brakes, you get 4 times the brake force.
This comes in handy for the parking brake, which is applied to the rear brake drum. The multiple effect gives you a good, strong parking brake that is less likely to give. Cars with rear disc parking brakes are prone to creep on hills once the brakes cool down. If you go to websites on manual tranny cars with rear disc brakes, you'll see that this is a problem. For a mainstream, high production car like a Corolla, this is a big issue.
Some luxury brands (Mercedes & BMW come to mind) actually have a rear disc and a mini rear drum brake which is exclusively for the parking brake. The added cost would not be feasible for a Corolla.
Rear brakes do significantly less than half of the braking on a car. That's why rear brake pads last so long. Old cars with front drum brakes tended to lock up and skid very easily when you slammed on the brakes. Since rear brakes take a huge amount of force to loock them up, drum rear brakes are fine for all except the most extreme stops. It's a design compromise, but you rarely are in a situation where it's an issue. It's a bigger issue if the front wheel lock up.
