We field, on average, just about 1.2 ka-billion questions a year about nothing other than brakes. After all, it's all we do....So one can only imagine some of the "doozies" we get. We've decided to post some of our more frequently asked questions here, in an attempt to save some of you the..... time, trouble, embarrassment, etc. Should we, in our attempt to educate however, miss a question, feel free to ask away, and we'll do our very best to accommodate.
Let's start at the beginning:
The number 1 asked question is.....(drum roll)....."how do I properly install my new brakes?"
First - we start off by removing the wheels. Do one side at a time, use a properly rated jack, jack stands, and CHOCK the wheels on the opposite end of the car from the brake job. .....Safety First.....
We recommend using a torque wrench.... (to take them off you ask,why?) Simple - when you remove the lug nuts - this is a good time to check to see what the torque WAS on your wheels to begin with! That favorite repair shop of yours may have used an impact gun to install the wheels the last time, and over-torqued the lug nuts in the process. Over-torquing lug nuts is one of the most common causes of warped rotors! You don't want to do this all over again do you?
Rule #1: Always use a torque wrench!
Rule #2: Inspect the caliper brackets and note the brake-pad to caliper contact areas. More on this later..... Once the wheels are removed, you can remove the caliper bolts and (if necessary) the caliper bracket bolts to remove the caliper bracket. Make sure you use a bungee cord, piece of wire, string, etc... to HOLD the caliper out of the way. Do not let the caliper hang by only the hose! Once these items have been removed - you can inspect the caliper brackets. Next, take a look at the inside of your old rotors. Notice the rust buildup on the inside of the rotor hat? Well, chances are it's not just the rotor that got rusty....
Let's look further.....
Rule #3:
Inspect inside of old rotor and note hub-to-rotor contact areas....
Rule #4: Inspect wheel hub and note any rust or buildup.....make sure the hub bearing is not sloppy or damaged, because now would be the time to change if needed......more follows....Now, let's take a look at the hub. Most newer vehicles utilize 'floating rotors'. This means that the rotor is separate from the hub. Floating rotors have the advantage of being able to be installed easier and do not require replacing the hub at the same time. However, one of the disadvantages of floating rotors is that are actually held on by the wheel. It is critical that whenever wheels are mounted and dismounted that the lug nuts are torqued to the proper setting.... Remember Rule #1? Tech note: Many older two-wheel-drive vehicles (amongst others) utilize a hub and rotor setup, where you would have to remove the hub nut, and the bearings in order to remove the rotor assembly. These units are typically more costly and require (by definition) changing the rotor AND hub. However, it is also less likely that these would be affected by improper wheel torque.
Rule #5: Clean all hub-to-rotor contact areas thoroughly! Okay....don your safety goggles....it's time to clean the surface of the hub. We suggest a 3M pad on an angle grinder - a wire brush or cup brush and rechargeable/electric drill will also give a similar effect. Do you notice any rust buildup and/or scale? Clean it off, make it look pretty! This debris is left behind from the inside of the old rotor. This small amount of debris, if left on the hub surface, could translate into .005" or more of rotor 'runout' if not removed! This means you could install a brand new, perfectly true rotor and still have the symptoms of a warped rotor!
We want to ensure that we have a perfectly flat hub-to-rotor mounting surface. Remember those caliper bracket things?
Since we're already in the cleaning mood - now might be a good time to clean up those areas where the brake pads and shims contact the brackets. Rust and debris here could cause the pads to stick, and cause uneven wear....
We don't want to have to replace the brakes any sooner than necessary...
Rule #6:
Clean all brake-pad to caliper bracket contact areas.
Rule #7: Clean all caliper-bracket to steering-knuckle mounting points as well as caliper to caliper-bracket mounting points. Also, the caliper-bracket to steering knuckle mounting points - as well as the caliper to caliper-bracket mounting points should be cleaned.
Mis-alignment of either of these items could cause the brake pads to wear unevenly. Now that we've cleaned those up - we can ensure that the calipers/pads - as well as the rotors will have straight-and-true surfaces for contact. This means less brake drag - and, by the way...better fuel efficiency! Did it ever occur to you that improperly functioning brakes is not only wearing out the parts faster - but costing you gasoline as well?
Rule #8:
Clean new rotors prior to installation to prevent contamination of the brake pads. Before mounting the rotors you should clean the inside and outside surface with brake cleaner. New rotors are typically shipped with a preventative (oil type) coating to inhibit rust.
This needs to be removed before assembly - otherwise it could contaminate the brake pads.
You wouldn't soak your brake pads in oil and then install them, would you?
Next, take a look at the caliper sliders and/or bolts. These are designed to allow the caliper to slide freely, back and forth, on the caliper bracket. They frequently become rusty and need to be cleaned or replaced. Otherwise, it could cause the brakes to 'drag' and create unnecessary wear on the brake pads. Also, while you're looking at that, take a look at the caliper pistons.The pistons should be in good condition and the rubber seals should not be broken or cracked.
Tech tip:
Inspect caliper pistons and seals for signs of deterioration and replace if necessary.
Rule #9: Lubricate caliper sliders for free movement. We like to use a high-temperature lubricant, such as a synthetic caliper lube or 'Anti-Seize' to lubricate the caliper sliders, and bolts. There are other brands available - and many of them seem to work well - and perform their function. We also apply a small amount of 'Anti-Seize' to the hub area where the rotor will be contacting it. Hopefully, it may make future dis-assembly easier. Whenever we don't have to use a sledge hammer to disassemble parts- it makes our lives easier......
Tech Tip: It may be necessary to compress the caliper piston in order to fit the new brake pads. Using one of the old brake pads and a large C-clamp will work. Many auto parts stores also sell an inexpensive tool to accomplish this. Some rear disc applications will require you to rotate the piston to compress, a special tool or "brake cube" should also be available at your local parts store
Rule #10: Replace or clean the brake hardware and shims prior to brake pad installation. Now would be a good time to install new brake hardware (eg. shims) and clean and/or lubricate the pad to caliper-bracket contact areas.
Now we're on the home stretch!
Tech tip: When installing the new brake pads - do not touch the surface of the pads with your fingers. The oils from your skin can contaminate the friction material.
Rule #10: Always use a torque wrench and torque the bolts/nuts to the correct amount! Now, we have come full circle. We are installing the wheels and using a TORQUE WRENCH to properly tighten the lug nuts/bolts.
We can't stress this enough: DO NOT USE AN IMPACT GUN! For professional installers: DO NOT USE TORQUE STICKS! Torque sticks have their limitations and will not compensate for your 450+ft.lb Snap-On impact gun!
Use a Torque wrench when installing the wheels and torque the lug nuts/bolts to the factory specified amount!
Once you have got everything put back together- don't forget this:
1) Follow the manufacturers' instructions for 'bedding-in' the brake pads.
Every manufacturer has slightly different instructions for pad 'bedding-in'. The procedure should be followed as listed - more is not better! We have 'bedding-in' instructions for the pad manufacturers that we carry listed on our website here:
http://www.raceshopper.com/tech.shtml#hawk_bedding
2) Follow the manufacturers' instructions for 'break-in' of the new rotors. Anytime new rotors and pads are installed, it will take a period of time/use for the pads and rotors to perfectly seat together. During this period of time- care should be taken not to thermally stress the rotors and pads. The more times that you can introduce a medium level of temperature into the rotors, and then allow them to cool, it will normalize the metal - and they will become stronger. Just like heat-tempering a tool - make sense?
Now, ask yourself this: The last time you had your brakes changed - did you or the installer follow these procedures? To some folks- this may seem like a lot of extra and unnecessary work..... However, wouldn't you rather have the job done right the first-time? Wouldn't you rather spend less time in the shop for brake repair and have the components last longer and save money in the process??
Take the extra couple of minutes it requires and you'll be much happier!
Mick Thorpe
RACEShopper.com
