Parking Brake Light On After Installing Front Brakes

alexpro · March 5, 2009

Hi,

I am very confused about this. After replacing the front brake pads on my 2005 RX330 I noticed the fluid in the master cylinder was about 1/4" above the max line. I wasn't sure if this would be a problem. I started up the car, pumped the brake pedal a few times until it felt normal and proceeded to take my test drive. Half way down the driveway the brake light came on. I did a google and found a few messages regarding low fluid. I removed the inner cap so I could soak up enough fluid to get the level just below the max line. The light is still on.

Anybody else have this problem or know what I need to do?

Thanks,

Alex

tjmc11 · March 6, 2009

Alex,

Keep in mind that the brake light can come on for various reasons. It will come on mainly because of the sensor in the cap of the resevoir is sending the signal. I think it may also come on if the ABS sensor is not working properly, but I could be incorrect about that.

I would disconnect the resevoir sensor line then reconnect it. I did that with mine and it worked. Some times the sensor in the cap will get messed up if too much fluid is in the resevoir.

alexpro · March 6, 2009

Alex,
Keep in mind that the brake light can come on for various reasons. It will come on mainly because of the sensor in the cap of the resevoir is sending the signal. I think it may also come on if the ABS sensor is not working properly, but I could be incorrect about that.

I would disconnect the resevoir sensor line then reconnect it. I did that with mine and it worked. Some times the sensor in the cap will get messed up if too much fluid is in the resevoir.

Hi, I disconnected the cable going to the resevoir and it didn't make any difference.. the BRAKE light is still on. I looked at the cap and I don't see anything in that cap that would work with or as a sensor. But I did find something out after I grabbed the box where I put the old pads in.

When I pulled out the old pads, I didn't realize there was a clip attached to the piston side pad. I'm thinking that clip has a purpose. Am I right?

Thanks,

Alex

tjmc11 · March 6, 2009

I think that clip is just a "squeeker clip" which will make noise as the pad wears down. I will look into the possible causes and post what I find. I will look o all data and see if any tsb's are out regarding the pad changes etc. I recall having to disconnect the cap wire on mine because the break lights came on. I will let you know what i find.

code58 · March 7, 2009

Hi,
I am very confused about this. After replacing the front brake pads on my 2005 RX330 I noticed the fluid in the master cylinder was about 1/4" above the max line. I wasn't sure if this would be a problem. I started up the car, pumped the brake pedal a few times until it felt normal and proceeded to take my test drive. Half way down the driveway the brake light came on. I did a google and found a few messages regarding low fluid. I removed the inner cap so I could soak up enough fluid to get the level just below the max line. The light is still on.

Anybody else have this problem or know what I need to do?

Thanks,

Alex

Alex- I'm probably not going to be much help on the clip because to me it looks like it is facing the wrong way (outboard) to be a "squeeker clip". Maybe not. The one reason I NEVER force fluid back upstream is #1 what you found out about it overfilling the M/C and #2 I have had problems in the past with it pushing the equalizer valve off center and having a hard time getting it re-centered. (I don't know if they even still have an equalizer valve but I imagine they do.) I prefer to open the bleeder valve just a little with the box wrench in my left hand and the large screwdriver type pry bar in my right hand. Place the pry between the rotor and the caliper in the opening in line with the bridge fins on the rotor (on the inside, towards the caliper piston). As you apply moderate pressure, open the bleeder a little to let it flow out until the piston is all the way retracted and immediately close the bleeder. There will be no air introduced this way and no fluid pushed the WRONG WAY back upstream. Much simpler and zero problems this way. Hope this helps in the future! Good luck with the light.

mikey00 · March 7, 2009

The clip you posted a pic of is the wear indicator. New factory pads come without one and is is nesessary to remove it from the old one and install on the new. New aftermarket pads usually come with the wear indicator built in. But that's not causing your brake light. Only problem is that when your pads reach the end of their life you won't hear a squeel. Also you won't find the fluid sensor built into the cap, it is part of the resovoir.

I think your light may be caused by pushing the fluid back as code58 said. I would try bleeding the brakes and see if it gets rid of it. Also may be worth disconnecting the battery cable for a few minutes to try and reset it.