So I recently changed front pads on both my cars. Interestingly, both had sensors which never went off even though both cars' pads were worn down to the backing plate. One had its last brake job done by the dealer, the other one was at the local shop when I converted to the R56 brakes. Since the sensors never went off and the pads I got from Way did not have suitable slots for them, I just tied them off with a zip tie and called it a day. Anyway, today the brake light went off on the 'vert. So I assume the rears need to be changed and they just about look it, too. The question(s) I have: 1. Do I need to replace the sensor, or can I just disconnect it? 2. How do I reset the light? 3. Anything else I need to know? Thanks.
If you're really cheap, you could rig the broken sensor to not trigger the light, but the sensors are only about $20 so it's probably worth just replacing it. You can also replace it with a new one and just zip tie it away from the axle, so that when you wear out your brakes, you won't have to replace the sensor again. You'll obviously have to keep an eye on your pads. I think you have an R53, in which case the reset protocol is to turn your key to position 2 without start the car and wait for 30 seconds. If the sensor has continuity, your light will go out. (There has to be a good sensor there to make the light go out: removing the sensor looks to the car like a sensor with the circuit broken and the light stays on).
Those things are a pain in the butt if you're not using them. The sensor has a little thin flat wire that curls around. If you wear down the pads and open the circuit, the light goes off. If you're feeling cheap, all you have to do is connect the two ends back together and close the circuit. Also FYI for anyone doing this to the front brake sensors, be careful where you zip tie the extra cable. Too close to the engine and you'll melt the wire or connector.
I though the flat copper wire was just to clip the sensor in? What two ends do you need to connect back together?
Yea gave up on them along time ago and practice the zip tie thing.... Change the pads back and forth so often for track that they were sorta redundant anyway.
There is a clip to hold the sensor on the pad. There is also an embedded wire in the sensor pad that will wear through and open the circuit causing the light to turn on. If you have worn through the sensor pad wire then you have two options to turn of the light. 1. Replace the sensor. It can be tie-wrapped out of the way if new pads do not have the slot. 2. Cut off the worn sensor pad and connect the two wires together to compete the circuit. This is a little bit of a pain because the wires are so small it is difficult to strip off the insulation and they do not solder together well (not sure material material the wire is made from but normal tin/lead solder does not adhere very well). Since the wires are so small it is also difficult to just butt connector crimp them together. The sensor wire can then be tie-wrapped out of the way. As Eric pointed out it might be easier for you to just replace the sensor rather than connecting the two wires together.
Thanks for the info, everyone. Now it is time for a rant: This country is going to hell in a hand basket. I just spent an hour and a half driving all over the neighborhood. Between Home Depot, Lowes, Sears, Harbor Freight, Pep Boys and Kragen not one of them carries a brake rotor micrometer. The most relevant answer I got from anyone was the teenager behind the register who claimed: "If we have anything like that it would be on the back wall". I will now have to source the damn thing online with all the profit going to some Chinese sweat shop and none to my local proprietor, or tax authority. It just makes me want to scream. /rant
I think you need the left-handed micrometer for the rotors. They're in the same place as the regular (right-handed) micrometers, but usually a little to the left.
What are you trying to measure, thickness or runout (warp)? A caliper should work fine for thickness (but not if you have a lip on the edge from rotor wear) Of course a micrometer can also be used for thickness. A dial indicator is needed for runout. I am surprised that Harbor Frieght did not have anything, here is from their website: Search results for: 'caliper'
Keep an eye out at flea markets. I got set of Starrett Mic's with a dial indicator at the local flea market a number of years ago from an old tool & die maker.
I am trying to measure thickness. I have a few rotors laying around and want to find out if it's worth machining them. Here is a HF tool: The thing is, it looks a lot bigger in the picture. In real live it is really small. I ended up buying this online for about $40 shipped: Central Tools / Central Lighting (CEN3M230) .300-1.300" Digital Brake Rotor Micrometer I think one of the vendors (Way perhaps) mentioned this before. As Quikmini mentioned there is a bit of a lip on the rotor from wear. Also, and I pulled this from some Lexus training manual, but it should hold true regardless of the model: The deeper micrometer should be better suited for that. At least that's my thought process.
There is a bit of a notch inward on the Harbour Frieght that will allow for measuring over the lip unless the lip is too deep and in that case the rotor gone anyway.....2 cents
Arguments like that do not help me in justifying my yet another tool expense to the wife. Just my 2 cents. :cornut:
Actually those Harbour Freight ones really suck for what you want, you need a digital brake rotor micrometer!!!!