OK this week we spend a little more time on the brakes. Last time we improved the ability to cool them… now we can try to push the braking system a little harder. I hope the ABS cooperates! We’ll know soon enough as our next test day is at the end of July.
So, one of the things you will encounter when you begin to track your 996 or GT3 (especially if you run race compound pads and tires) is that you will begin to generate massive amounts of heat in the braking system. The 911 will stop on a dime if set up for the track and the brake pad wear sensors can literally burn up as installed. This will of course cause the brake warning light to stay lit all the time. Porsche, Pagid & others actually recommend that you do not run the pad sensors when you track the car.
There are two things you can do about this:
A) You can remove the sensor wires before each event. If you are the type that spends a lot of time prepping before an event this may work fine for you. This works well especially if you do pad changes for track events. Note that when you simply pull the sensors out of the electrical connector located on the back of the hub, the brake pad wear light will come on. Another alternative is to pull the pad sensors out of the pad before they fail and fold them up and tie wrap them out of the way. This is a good intermediate step before you make the decision to disable them entirely.
B) If you are like me, and you run race pads on the street and DOT race tires which you leave on the car for extended periods, you may prefer a more permanent option. Below I have outlined my particular method for disabling the brake warning light when you don’t use pad sensors.
Here is a photo of the complete Porsche brake pad sensor wire. On the left you can see the plug that goes into the electrical connector shown below. On the right you can see two “pins” that are each inserted into holes drilled into the side of the brake pads. When the pad wears, these pins grind down and expose the wires that are looped around them. Eventually the wires break and the circuit is broken. So we are going to modify the wear sensor wiring so that the circuit remains permanently intact.
First, locate the electrical connector on the back of the hub carrier. It’s located on the back of the hub carrier just above the outer CV joint. Flip up the metal clip that locks the connectors in place. Trace the wires back to their sources. One goes the the brake pads and the other is your ABS sensor. It’s quite obvious which is which. Remove the brake pad sensor plug and pull the entire sensor and wiring off of the car. The pins in the pads just pull out.
Now with the pad sensors completely removed you will cut the rubber wire sleeve and wires about 2″ from the white plug end of the sensor. Then strip the wire ends so that you can twist the two wires together. Put a crimp connector on them and then re-attach a small section of the rubber heat protection tubing to keep out the dirt and moisture. Fold over the tubing and seal it off with a tie-wrap or similar. Voila you are done. No more brake pad warning lights. Ever.
The photo above shows the wires stripped. It is for explanation only. In actuality you will not leave the wires anywhere near this long.
Shown on the left here is the brake pad wear sensor wiring in it’s final state. Plugged back into the connector with the short ‘pig tail’ of wire all sealed up inside the rubber sleeve. All in all a simple mod.
Should you ever wish to return the car to its original brake wear functionalty, the sensor wires can be purchased for under $10 per side.