Changing REAR Brake Pads for Beginners!
by Richard T. Lin (aka Octaneguy)
CAUTION: PROCEED AT YOUR OWN RISK
As with all mods or DIY articles, the information provided here is without warranty. I am providing the steps for your information, but beware that problems may occur and that you accept full responsibility. Should you encounter any problems, please take a deep breath and post your problems to the thread (see link at the bottom) and we will all do our best to assist you. I am not a professional mechanic. In fact, this was my first time working on brakes, but I spent many weeks researching this subject.
MINI REAR Brake Pad Installation
Changing your brake pads is a very rewarding DIY project. This tutorial focuses specifically on giving you the complete picture on how to replace your OEM pads and Brake Pad sensor for the front axle. After you've done this yourself, changing the rotors or upgrading to aftermarket pads is a breeze!
I noticed a yellow symbol light above my OEM nav system next to the seat belt warning light, indicating that one set of my brake pads needed replacement. After some investigating, it was determined that the front set needed replacement, and I decided to wait for the rears. Well, the sensor light came on again a week later, which turned out as expected to be my rear brake pads.
Remember, our MINI's have 2 sensors, one on the front left wheel and one on the right rear.
Although I had previously changed my front pads with OEM pads because I wanted to familiarize myself with the brake sensor, I decided when it came time to do the rears, I would go aftermarket and replace front and back at the same time. I chose Mintex Red Box pads because a full set costs less than just the front OEM or EBC brakes and they are supposed to dust less than OEM.
The only drawback which I find pretty confusing among brake pad manufacturers is whether their pads support the brake pad sensors on my 2003 MC. But since I regularly rotate my tires and know how to determine whether the pads need replacement or not, not having the sensors isn't a big deal.
You will need:
7mm Allen Socket
Brake Caliper Tool Kit
Jack Stands/Racing Jack
Replacement Brake Pads
Rubber or Mechanics gloves
1/2" to 3/8" adaptor
Replacing the brake pads is simple. You remove 2 bolts which frees the caliper/piston assembly. You replace the old pads with new ones, and put it back together. The trick lies in compressing the piston. With the front brakes, you just push it in, with the rear brakes you need to use a tool that pushes in and twists at the same time, so the Brake Tool I show here is the idea tool to have. Each wheel will probably take between 20 to 30 minutes.
Lay out your tools
Make sure you have all your tools. Nothing is worse than finding you need to put your car back together to drive to your nearest auto parts store to find that missing tool! (I did that for this article!)
A set of these can be very handy when you find you just don't have enough room to reach your bolts!
View of the rear caliper piston.
Harbor Freight caliper tool set
You will only need the main tool in the center of the picture--looks like a part of a C-Clamp, and the curved flat plate below it. The rest of the adaptors are not used with the MINI.
Brake pad sensor
The brake pad sensor (small end) consists of a long wire that connects to the front left pad assembly. The other end (Cylindrical end) goes to a receptacle that's hidden by some of the paneling.
Brake Pad Thickness
Just by looking down the brake rotor, you can see the thickness.
We're going to lift the MINI up on jacks. But before we do that, make sure to loosen the lug bolts. If you lift the MINI on stands before loosening your lug nuts, you won't be able to remove the wheels! The OEM wheels come with this little tool to remove the hubcap.
17mm Socket and Breaker Bar
If you plan on working on your car frequently, get atleast an 18" breaker bar. It makes removing the lug nuts much easier over using the spare tire kit that comes with the Cooper.
Breaker Bar is Hinged
You can turn the breaker bar at a 90 degree angle to remove the lug bolts, then straighten it out and spin it with your fingers to remove the bolts.
Use a Coffee Can to Hold Loose Parts
A coffee can works great to keep all the parts you removed in one place!
To keep the MINI from rolling, chock the wheels on the opposite side that you are working on, shift the car into gear and do NOT pull the handbrake. With the handbrake up, it will be impossible to compress the pistons!
Lifting the MINI
The MINI has 4 jacking points. The rear wheels don't have a decent alternate jacking point, but because the MINI is so rigid, you can just put a jack under the front support point and jack up the car, then use a jack stand on the rear most jacking point. I jacked one side only at a time.
This wire actually holds the two parts of the brake calipers together. It's a good idea to take a picture or print this page out as a reference.
Removing Retaining Wire
To remove the clip, insert a flat bladed screw driver on the lower portion of the clip at this point, and simply wiggle it off. Inserting it at this location is the easiest way of removing it.
Full Brake Assembly
Part remaining on rotor
As you can see here, this part stays on the rotor. It actually loosely holds the outer brake pad. If you wanted to remove this part of the brake assembly, you would need a 16mm socket to remove 2 bolts, but for just changing brake pads, they will remain as they are.
Brake Calipers Removed
This assembly holds the inner brake pad. The piston is a part of this component and isn't very visible here. It's what pushes the brake pad against the caliper when you step on the brakes.
It should be pretty clear now that there are 2 major parts here. Each component holds each side of the brake pad. There are 2 parts to the brake pad. The one with the wire side faces the inside of the car, while the flat pad faces out.
Brake Pad Sensor
The wire you see in the middle here, is the wire for the brake sensor. This wire can be found on opposite corners--the Left Front Wheel and Right Rear Wheel.
Disassemble Caliper Assembly
To take apart the brake assembly, you only need to remove 2 screws. They are hidden behind these plastic caps. Just use your finger nail to remove the cap and insert a 7mm Allen.
7mm Allen socket
This is the tool you need. I could only find it for a 3/8" ratchet. Because I wanted to use it with my 1/2" Torque Wrench, I bought an adaptor to convert my 1/2" drive to a 3/8" socket.
Set of Adaptors
I found this set at Pep Boys. Figuring I may need this in the future, I decided to buy a set of adaptors for $10.
It Doesn't Fit!!
It should be evident here that a 3/8" Allen Socket won't fit a 1/2" Drive ratchet
An Adaptor Saves the Day!!
Now it fits!!
7mm Allen bolt
You can't see what the 7mm Allen head looks like because it's facing away from you.
Loosen Allen Bolt
Using a ratchet, just loosen the bolt.
Loosen By Hand
Once you've loosened the 7mm Allen with the ratchet, remove it, but leave the socket in place, and just use your fingers to remove the Allen bolt.
Because of the location of the brake lines on the lower bolt, you will need an extension to clear the line and fit the ratchet inside.
If you look closely at where the Allen bolts travels, you can actually get your fingers in there to help the bolt come out.
Once you are sure the 7mm Allens have been loosened and removed, you can slip off the caliper assembly. It will need to be wiggled quite a bit.
You "may" be able to use a screw driver to pry the caliper off by being very careful. You should pry against the brake pad backing plate since this will be discarded. The piston will be fully extended making extraction a little difficult.
On to the Piston!!!
Ok, you can see the piston here. It's that large cylindrical part with a rubber boot. In order to compress this so that you can insert the brake pads and put it back on your rotors you need a tool!
This is the tool from Harbor Freight.
However just putting this on the caliper won't do anything. The tool needs to both rotate AND push the piston in.
So make sure you add this plate and place it correctly.
You will crank this part clockwise to drive the piston in.
As you crank the piston in, this little plate will get loose. You just need to tighten the little nut behind it to take up the slack that you've created by compressing the piston. You will probably have to do this 4 or 5 times before the piston is fully compressed.
Don't Let Rubber Sleeve Bunch Up
As you compress the piston, be careful that the rubber sleeve doesn't bunch up, and tear. Just carefully adjust it as you compress it each time.
Because I'm using Mintex pads that don't support the brake pad sensor wire, I'm just going to replace it with a new one and attach it with zip ties in some location that won't interfere with the safe operation of my MINI.
Ending Time (Side #1)
This is where I stopped with the first pad. Took me about 40 minutes since I was taking photos, and figuring things out. Then I did the other side in about 30 minutes, but I didn't replace the sensor wire yet.
There wasn't anything particularly difficult about putting everything back together again. Just slide the caliper assembly on, and tighten the 2 Allen head bolts.
Caliper to brake pad carrier (7mm Allen) 30 - 5 Nm or (22 - 4 ft-lb)
Even with the 2 Allen bolts secure, The assembly may feel a little wobbly, because the piston is no longer applying pressure to the brake pads. But once the retaining clip is put back on, the assembly will feel very solid.
Slip the retaining wire into the top hole first and use pliers to insert the bottom portion of the clip into the lower hole. It will take some force to do this. With the front side supported by the racing jack, just lift it up a bit higher and remove the jack stand and repeat on the other side. Now torque the lug bolts to the proper spec. Abound 88Nm using the torque wrench. Tighten opposing lug bolts as you do this. Replace the hub caps.
Get in the MINI, and turn on the ignition. The first time you step on the brake pedal it should go to the floor. Also the eBrake will feel very loose, but don't worry. Pump it a few times and it should feel like normal, although it may feel a bit spongy. Take a drive around the block being careful to ensure that the brakes are operational. Return back to your work area, and retighten lug bolts to 88 ft-lbs .
Ending Time (Side #2)
I spent time taking pictures and preparing this article, but as you can see, it won't take long to do your brake pads the first time!
With proper instruction, anyone with the right tools can do this simple brake pad change in as little as 30 minutes! Of course if you don't feel comfortable working on something as critical as your brakes, get a qualified mechanic to do the job!