I hate these screws. Most European cars don’t even have them, but for some reason the Japanese feel the need to equip their cars with them. The reason they are there is to hold the rotor securely to the hub of the car once the wheel is removed. If you look at how the whole assembly of hub/studs, rotor, wheel, and lug nuts fits together, you will see that these screws serve no purpose once the wheel is installed. The screws exist merely as an unnecessary assembly aide.
Their function is so superficial, in fact, that they are made out of what must be the softest metallic substance on the entire car. Under any load from the brakes, I can imagine these screws’ heads popping off instantly. Alas, they are on the car holding the rotor in place and must be removed in order to change rotors (another insufficiently designed component of the Honda/Acura braking system, but that is another blog topic...) The process of removing these screws appears to be as simple as grabbing a phillips head screwdriver and giving them a twist.
Unfortunately, life creates it’s own interesting moments when it is realized that even a very minimal amount of unseen corrosion or galvanic action LOCKS these bad boys in place, causing the screws to strip with ease. Once these guys are stripped, you need to grab a drill and bore out the heads to get them off. I have done this drilling more often than I have had the miraculous joy of actually removing the screws properly. I never want to do it again.
Let’s say, I were to stop writing here. One might no doubt search their favorite message forum and read all of the wonders of a tool called an impact driver. This tool is a sort of screw-driver with a spring-loaded twisting action that works when the handle is hit with a hammer. The idea is, the hammer forces the driver into the screw while the spring action twists the screw just enough to break it free. Much of the time, and impact driver is the perfect tool for the job. But I content this method is no sure-fire way to unscrew these screwy screws without possible need for the drill.
Problem one with the driver is, not everyone has one, and not everyone who changes brakes every 2-3 years wants to buy one. In order to get one that works reliably, you’ll need to spend enough money that you might well have paid someone to do your brakes for you. I’ve used cheap ones, and broken them almost instantly. Bonus…before they broke, they stripped the screws.
Problem two, even with a good driver there exists an estimated 10% chance you’s strip a screw anyway because the screws are just that bitchy.
So here is my SURE FIRE, WORKED EVERY TIME I DID IT WITHOUT FAIL way of removing the rotor screws from your brake rotors. It involves two simple tools nearly everyone has in their tool box.
Now it is all about technique. Make a dimple in the screw head near the outside diameter of the screw. You just it need to dent the screw a little, not chop a chunk into it.
Using the dimple for “traction,” hold the chisel about 45 degrees from the rotor hat (make sure you put the dimple in a place not directly adjacent to a stud) and give it a few good whacks to work it free, and you’ll need to rotate your position as you hit to walk the screw around.
Use a screwdriver to spin the screw out! No new tools. No special tools. Hell, you can use the crappiest hammer and screwdriver you have. The real trick is not to get too wily with your chisel because you can make mince-meat out of the screw, making the job harder and making the potential for getting that drill out a reality. With a bit of practice, you can get this process figured out before you are done changing 4 rotors.
With the screws removed, go about the business of changing rotors, and if you are re-installing the screws. You’ll have to deal with them again later though. For this reason, I usually toss them in the trash. If these are intended to make my life easier, I wonder how things would be designed if designed to work against me.
GEEK TIME! Why does this work?
It works because when driving a screw with a screwdriver or an impact driver, the majority of the twist happens very close to the center of the fastener, imparting a minimal amount of torque to the screw (remember, torque is force x distance). In order to get the amount of torque needed to remove the screws easily, force must be applied to to a point on the fastener as far from the center of the fastener as possible. In T = Fd, you are increasing d.
Likewise, a screwdriver has a tendency to impart minimal grip on the screw itself, which is why when you turn it the driver want to naturally pop out of the head as you twist. This reduces the force you are able to put into actually turning. In order to get a screwdriver that really grips screws well, you need to come out of pocket more than you might want. You will find yourself putting lots of effort into shoving the driver into the screw to prevent this action even with better tools. A quality impact driver that will handle the extreme hammering that is needed sometimes is even more costly than a good screwdriver! When using the chisel method, the force you impart on the screw is concentrated in a localized area where it does the most good without any “fighting.” It is easy to remove the screws because so much of your effort goes into doing work, not to counter ancillary tendencies. In T = Fd, you are effectively increasing F.
There you go. All you wanted to know about getting the rotor screws out on your Honda/Acura…and more. Too much maybe.