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      08-20-2012, 10:31 PM   #1
canadian stig
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Drives: 2008 E90 M3
Join Date: Jan 2012
Location: canada

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A few brake pad replacement + Wear sensor delete tips and thoughts

After 7 track days the oem pads were practically worn out. So I replaced them today with stoptech pads and also took the opportunity to delete the 3 wear sensors. Since I track my car a lot I regularly check the brakes myself and don't need wear sensors. Besides, they usually melt from the heat and malfunction anyway. I won't go into too many details since there are already a few DIY on this forum. I will just add my tips and thoughts.

1) I've changed brakes on many cars before and none were nearly as bad as this car. Easily the WORST and most inconvenient brake job I've done so far. Keep reading for reasons.

2) The rubber sleeves protecting the caliper pins are incredibly annoying. They make it impossible to turn the pins by hand or pull them out once loose. You will need to keep using the wrench to turn the pins all the way till the end. Once loose, pull them out with needle nose pliers or pry them with a screw driver at their threaded end just outside the caliper carrier. If you don't pull them out you may not be able to remove the caliper even if you loosen them all the way.

3) This step is optional if you aren't replacing rotors, but I decided to clean the rotors from both sides, so I had to remove the caliper carrier. Doing so makes it much easier to disconnect the carrier from the caliper itself. If you don't do so, it may be impossible to remove the caliper without first compressing the piston. The reason is that if the pads are too worn out, the caliper slides inwards towards the inside as the piston protrudes more outwards to compensate for pad wear. When this happens the caliper slides onto the carrier at the outer end and the only way to slide the caliper back out to separate it from the carrier is by compressing the piston.

4) Those stupid clips that hold the caliper to the carrier at the outer edge are a serious PAIN to remove and install.

5) If you unclip the brake hose from the strut for the front calipers it gives you lots of slack and makes moving the caliper around much easier.

6) The brake sensors are very fragile. None of the 3 on my car was salvageable. They all partially melted and fused to the pad, likely due to the heat during tracking. None of them would pop out of the pad intact. They all had pieces broken from them when i yanked on them. I don't know why our cars use those stupid sensors instead of the traditional sensor that just rubs against the rotor and gives off a squealing sound.

7) My sensor delete was a bit different from another member who posted a DIY here. If your sensor was intact you can just zip tie it out of the way. Since mine broke up when removing them, I had to complete the circuit myself or else I would have gotten the brake service light. I just cut off the wires right where they enter the L-shaped sensor itself. Then you just slide off the outer rubber cover off the 2 wires inside.

The 2 wires are colored red and yellow.

Just remove a bit of insulation from the ends of both wires. Then join the two wires together and wrap them with electric tape.

I personally used electric tape to also tape the sensor wire back to its own clip that's holding the wire to the strut so that it's tucked out of the way. But you can zip tie it to the strut or control arm if you want.

8) The rear rotors were a SERIOUS PITA to remove. They were almost WELDED to the hub. The left one took me almost an hour by itself to remove. The right one came out in about 15 minutes or so but only because I had already figured out the solution to the problem from experimenting on the left rotor. What I did was spray penetrating oil on the hub. Then I used a tire iron to pry on the rotor. I jammed the tire iron between the rotor and those round metal mounts where the caliper carrier is bolted to. I then added an extension bar onto the tire iron to maximize torque and hammered onto this extension like a mad man for a couple dozen times or so till it finally came off. I did the same for both sides and the rotors finally came off.

To prevent a similar problem in the future I put some high temp brake grease onto the hub to prevent the rotor from sticking to it. I have no idea when was the last time the rear rotors were removed so I can't be sure how many years of corrosion made them stick like that. But I personally recommend removing the rotors at least once every 1-2 years even if you aren't replacing them, just to eliminate any corrosion before it gets out of hand.

Last edited by canadian stig; 08-20-2012 at 10:52 PM.