Introduction: Repair Car Front Brakes
Hello and welcome to my Instructable on how to repair your front brakes even better than some mechanical workshops!
Throughout the steps I'll show you how to not only replace your brake pads but measure and recondition your brake rotors for optimal performance and efficiency!
Step 1: Removing the Brake Pads.
First of all what your need to do is safely lift the car, whether you're using a hoist or a jack to lift the car is your choice, although if you are using a jack make sure you use axle stands!
After you've safely lifted the vehicle you'll obviously need to remove the front wheels.
Now, the car I'm working on today is a 2001 Nissan Pulsar, Most front braking systems are the same or very similar to the one on this car. Looking at the brake caliper you'll notice 2 small bolts holding the caliper into the bracket. Remove the bottom bolt and lift the caliper up, exposing the brake pads. From here, push the caliper back so the slide moves out of the bracket and rest the caliper somewhere (careful not to put stress on the brake line) I usually sit mine on the spring.
You can now remove the brake pads :)
Step 2: Measuring Your Rotors.
Now that we have the pads removed the next step is to measure your brake rotors, This is important as having undersized rotors can be very unsafe on the road.
First thing we need to do is grab our trusty vernier calipers and zero them in, making sure your verniers have little points on them as brake rotors generally form a lip due to the pads friction area not being the full area of the rotor.
To zero in your verniers simply put the points together and press zero!
Now open them up and place them over your rotor, close the points onto the rotor and move it around a little to find the lowest point, THIS is your measurement.
The next thing we need to do is find out what the manufacturers specification is for the minimum thickness of the rotors, For my Pulsar, Nissan has said 20mm is the minimum thickness and mine measure in at just over 21mm so they should be alright for the next step! Resurfacing/Machining the rotors :)
If they're too close to the manufacturers minimum thickness then you'll need to order replacement rotors, They can be expensive but putting new pads onto rotors with and old worn down surface will just cause your pads to wear faster and can lower your braking performance!
Step 3: Machining Your Rotors!
First you will need to remove your rotors, do this by removing the 2 bolts on the bracket for the brake caliper, after this your rotor should come off, some rotors have screws you need to remove before hand and some just get a bit seized on with rust, a tap with your hammer should get him free! (Tap around the studs as the friction surface can be brittle)
After your rotor is off we'll head of to the disc machine, you will have to find a bowl that fits inside your rotor nicely and slide it onto the shaft, place the spring on next followed by a cone that fits through the center hole of your rotor the cone should centralize the rotor on the brake lathe.
We will then slide the disc on, followed by another bowl, this one is simply to push the disc into the cone. We'll then select the appropriate spacers, followed by the nut and make sure the nut is tight! (Most of these brakes lathes are reverse threaded so keep that in mind when tightening the nut!)\
Switch the machine on to double check the rotor isn't moving around and is set nice and even, make sure the fasteners for the blades and the slide are loose then move the slide in so the blades are sitting in the smallest bit of the rotor. Adjust the blades in so they only just touch (Barely cutting) and slide the blades to the outer edge to cut off the lip.
After the lip has been cut, move the blades all the way to the inner edge, from here we'll zero in the gauges (Depending on the design of the lathe hold the outer circle of the blades adjustment and turn the inner circle to 0) after the gauges are zeroed in, move the blades in 2 notches, tighten the fasteners for the blades and slides and click feed, you should be seeing (and hearing) your rotor being cut.
If it's not a perfect cut the first time do not stress! Simply undo the fasteners again, move the blades back in and take another 2 notches off.
1 notch normally equals 0.004mm.
Step 4: Reassembly!
Removed the slide from the caliper bracket and clean it with a rag then apply a thin layer of grease (High temperature grease is better for this application!), do the same with the slide still attached to the caliper. This allows the slides to move freely giving you more economic braking, a seized slide means your brakes can wear unevenly!
Reinstall the rotor you machined, Or install your new rotor! If you've purchased new rotors be sure to clean them with brake clean and a rag before installation as they are normally covered in an oil film to prevent rust.
Reinstall the brake caliper bracket, then install your brake pads. The pad with the wear indicator (Piece of metal on the side) should go on the back as it's the side with the piston and is more likely to wear faster.
Place the caliper back into the bracket and before pushing the piston back, removed some brake fluid from the reservoir, I used a pneumatic brake bleeder. Squeeze the piston back being careful not to damage the rubber boot, you can buy specialized tools for this but I'm simply using a big pair of multi-grips. After the piston's in lower the caliper and tighten the bolt!
Put the wheels back on and lower the car down, before you drive the car be sure to pump the brake pedal a few times and check the fluid level.
Some pads require you to bead them, which is the slow build up of heat and then the slow release of said heat. I simply drive at approx. 80km/hr, slow to 60, slow to 40 then drive around for a few minutes and brake hard at the end. If your brakes feel like they take a while to stop or take a lot of force, chances are you need to bead them in!
Thanks for reading, I Hope my instructable was helpful and your car is now stopping safely :) Take care!