Changing front rotors/brake pads

[Esteves]

Just for kicks, went to an independent shop to see how much they would charge to replace front rotors with Euro Floating Rotors and change out the front brake pads.

$150

Okay, now that I know how much I'm saving, went home and got to work.

Now, this is for those who would like to swap out their rotors, but wasn't sure if they had the mechanical know how. Hopefully this will help.

When replace rotors, it's a good idea to replace the brake pads as well, so be sure to have fresh brake pads.

1. Loosen the bolts on the wheel. In case you don't know, you'll need a 17mm socket. If you've got a breaker bar, that works great.

2. Jack up the front of the car. It doesn't matter which side you start off with, but I started with the driver side so I suggest to do the same for all of this to make sense. Remove the wheel.

3. Remove the caliper clip. Use a screwdriver wedged against the rotor and force the clip towards the rear of the caliper (there should be an arrow pointing in the direction you are suppose to push, but it is most likely covered in brake dust). Use another screwdriver to lift it off its housing. Warning - it may snap and fly off somewhere. Go get it.

4. Removing the brake pad wear sensor. There is only one on the driver side (none on the passenger side). Also, there is a brake pad wear sensor on the passenger rear, but not on the driver side rear. Why? Who knows... Anyhow, carefully remove the brake pad wear sensor. You may need to use needle nose pliers to get at them, but be careful not to CRUSH the brake pad sensor.

5. Remove the plastic caps that are covering the caliper guide bolts. The caliper guide bolts need an 8mm hex bolt to remove. There are two of them. Once loosened, you may need to use a small screwdriver to push out (but not completely out) the caliper guide bolts. The bottom caliper guide bolt is a little difficult to push back, but be patient. You need to make sure the caliper bolts are completely out of the way in order to remove the caliper. Like everyone says, don't let the caliper hang. Find something like a shoe box to hold it up.

6. Pull out the old brake pads.

7. Now for the part I had the most difficult time with. Removing the caliper mount bolts. The caliper mount bolts use a 16mm socket to remove. Mine were torqued on VERY TIGHT. I had a 1/2 inch socket wrench driver and still had a hard time. It can be done, but requires a lot of muscle. When you remove one bolt and loosen the other, keep one hand on the caliper mount so that it doesn't fall onto your rotor when the second bolt comes off. If you don't care about your rotor, than don't worry about it. Remove the caliper mount.

8. The rotor is held onto the hub with a small screw. The screw uses a 7mm hex bolt. Remove that. The rotor will most likely have rusted onto the hub. Now comes the fun part that everyone talks about. Take a hammer and give that rotor a FORCEFUL WHACK to loosen the rotor from the hub. If the rotor doesn't come off, increase the force. Remove the rotor.

9. Clean off the hub and then apply anti-seize compound on the hub where the new rotor will make contact. Place the new rotor on the hub. Screw the bolt (using a 7mm hex bolt) back in place that holds the rotor onto the hub.

10. Return the caliper mount back into place, being careful not to scratch your new rotor.

11. When you remove the brake pads from the caliper, you'll notice the brake cylinder out. You'll need to push the cylinder back into the housing. You can use a plank of wood. I highly suggest investing in a disc brake caliper tool set. You'll find it VERY handy on every vehicle you have.

I suggest this set from <a href="http://www.thetoolwarehouse.net/shop/AP-7860.html">The Tool Warehouse</a>

It's a nice set, very reasonably priced.

Anyhow, before attempting to push the cylinder back into the housing, be sure to remove the cap off the brake fluid reservoir. Watch out for any overflow that may occur when you push the cylinder back into the housing. Put the cap back on when you are done.

12. Once the cylinder is pushed back in, put the new brake pads on. I placed a small amount of anti-seize compound on the back of the brake pads that make contact with the caliper.

13. Return the caliper to the caliper mount and bolt it back on.

14. If you want to use this opportunity to flush your brake fluid, go right ahead. Here is a great reference on bleeding your brakes courtesy of Ron Stygar. Click <a href="http://www.unofficialbmw.com/all/brakes/all_changing_brake_fluid.html">here</a>.

15. Return the wheel to the hub and place the wheel bolts back on.

16. Torque the wheel bolts to 88 pounds and you are half way done.

17. Now go do the passenger side now that you know what you are doing!

Also, here is another great reference that could be helpful in changing rotors/brake pads. Again, courtesy of Ron Stygar. Click <a href="http://www.unofficialbmw.com/e36/brakes/e36_changing_brake_pads.html">here</a>.

Now that you've saved yourself $150, go buy something for yourself!

[Pinecone]

Be VERY careful on the first drive if you change both pads and rotors at the same time. Many experts suggest you do not change both at the same time.

[alpinewhite325i]

Originally posted by Pinecone
Be VERY careful on the first drive if you change both pads and rotors at the same time. Many experts suggest you do not change both at the same time.

Why? I just changed mine...and didn't have any problems besides driving gently to break them in.

[Nick325xiT 5spd]

Originally posted by alpinewhite325i
Why? I just changed mine...and didn't have any problems besides driving gently to break them in.

The theory is that they may break in better if one of the components in the system has already been thoroughly heat cycled, so far as I can tell.

That said, there's really no harm in it. You just have to bed them in properly.

[JetBlack330i]

Thanks for the write up.
I did both axles (on wife's car) and estimate that I saved $400. That was more than sufficient to buy myself a torque wrench and a nice aluminum floor jack (http://www.bimmerfest.com/forums/showthread.php?s=&postid=320631#post320631) .
In step 12, you forgot to mention using anti-squeek paste. Put paste on the back of the pads, everywhere that contacts the calliper and piston.
Also since you have the calliper out, it's a great opportunity to spray it with brake cleaner. You'll need about 1 can per axle.

[alpinewhite325i]

Originally posted by Nick325xiT 5spd
The theory is that they may break in better if one of the components in the system has already been thoroughly heat cycled, so far as I can tell.

That said, there's really no harm in it. You just have to bed them in properly.

gotcha :thumbup:

BUT....I always thought that if you were putting new rotors on...it was basically required (recommended) to put on new pads as well.

[Zeegar]

On Steve Bernstein's brake bleeding instructions he says to bleed the CLOSEST caliper 1st (see # 6), most instructions say start with the passanger rear.

Which is it and why?

Thanks


Bleeding Brakes

1. Some folks like to replace the fluid in the reservoir prior to flushing the lines. Some have been insensitive enough to use kitchen utensils (like turkey basters) for this task. This has been known to cause family unrest, and the author of this FAQ suggests you find an alternate solution for the sake of your family. Truly, unless the fluid is excessively dirty (very dark), this really isn't necessary.
2. Assemble the bleeder as discussed by Al and Jon below.
3. Put about a half quart of your favorite fluid into Tank #1 and tighten the lid. Refer to your owner's manual for DOT specification if you are unsure. Unless you are a driving school veteran and are attending more than 10 track days per year, I don't think it is necessary to waste your money on racing fluids.
4. Replace cap on the reservoir with Cap #3 and make sure you have a good seal.
5. Pressurize Tank #1 to 10-15 psi. Check for leaks.
6. Start with the caliper closest to the brake fluid reservoir. You might step on the brake pedal once or twice to get the fluids moving.
7. With the brake line closest to the fluid reservoir, open your caliper nipple. With the first line, you want to completely replace the fluid in the reservoir with fresh fluid (unless you did this prior to beginning). Close the nipple when the fluid is very clean and when you see no more air bubbles.
8. Work your way towards the longest brake line's caliper and repeat this procedure.
9. For completeness, I like to repeat the procedure again to make sure there is no more air trapped in the system. If you have replaced brake lines or rebuilt calipers, and have introduced air into the system, it is imperative that you repeat the procedure. Otherwise, use your best judgement.
10. One other note is that it has been suggested that one start with the line furthest from the fluid reservoir, but until someone can give me conclusive evidence explaining why this works better, I'll stick with this for now.
11. After you are finished, release the pressure in the tank by pushing down on the valve release... then

[Pinecone]

There are supposed pros and cons for each way (longest to shortest or shortest to longest).

But if you are going to do it twice, I don't see that it matters which order.

The order has to do with trapping a small bubble or unclean fluid at the junctions.