Mountainrider
02-01-2009, 01:05 PM
I did a sticky about brake fluid leaking through the brake warning switch. The problem started when the grommet under the front reservoir cracked and leaked all the brake fluid out. This caused the piston in the proportioning valve to move
in its bore. That causes the plunger on the warning switch to jump out of the grove in the piston so that when you apply the brakes brake fluid will be pushed through the switch and you will see droplets of fluid on the valve covers and the reservoir will empty out. This is all that you need to fix this problem (after fixing the grommet).UP DATE: A little clarification is needed here. I said that the proportioning valve piston moved in its bore and caused the plunger to jump out of its grove and that that caused the switch to leak. That’s not true although it did cause the brake warning light to come on. The leak is from another problem that came about at the same time. There is a small o ring inside the piston that failed and allows the brake fluid to get inside the piston and through the vent hole that’s in the grove.
http://i430.photobucket.com/albums/qq28/mountainrider_photo/P1010161.jpg remove the cap. Use a socket because the cap is aluminmun and a wrench will screw up the cap. Trust me I almost did that.
http://i430.photobucket.com/albums/qq28/mountainrider_photo/P1010160-1.jpg Then remove the spring. You can see the piston in this photo I have already moved the piston into place deeper in the bore. The piston needs to be all the way into the bore.
http://i430.photobucket.com/albums/qq28/mountainrider_photo/P1010159-1.jpg I used a pick to pull the piston out of the master cylinder housing. Once I alined the grove in the piston up with the hole where the the switch screws into I installed the switch. If you don't get the grove alined your warning light on the dash will be on.
http://i430.photobucket.com/albums/qq28/mountainrider_photo/P1010162.jpg
When you have the piston out there is a sheetmetal cap on one end remove that cap. Under the cap is what looks like a button it is a small plastic piece of tubing about 1/4 inch long with a metal dowl inside the plastic. if you remove those pieces there is a small oring inside thats where the leak is. replace that oring and the leak is fixed.This is the tools to do the job. 15/16th socket,brakerbar,pick , 14MM wrench and brakeclean.:Irule:
in its bore. That causes the plunger on the warning switch to jump out of the grove in the piston so that when you apply the brakes brake fluid will be pushed through the switch and you will see droplets of fluid on the valve covers and the reservoir will empty out. This is all that you need to fix this problem (after fixing the grommet).UP DATE: A little clarification is needed here. I said that the proportioning valve piston moved in its bore and caused the plunger to jump out of its grove and that that caused the switch to leak. That’s not true although it did cause the brake warning light to come on. The leak is from another problem that came about at the same time. There is a small o ring inside the piston that failed and allows the brake fluid to get inside the piston and through the vent hole that’s in the grove.
http://i430.photobucket.com/albums/qq28/mountainrider_photo/P1010161.jpg remove the cap. Use a socket because the cap is aluminmun and a wrench will screw up the cap. Trust me I almost did that.
http://i430.photobucket.com/albums/qq28/mountainrider_photo/P1010160-1.jpg Then remove the spring. You can see the piston in this photo I have already moved the piston into place deeper in the bore. The piston needs to be all the way into the bore.
http://i430.photobucket.com/albums/qq28/mountainrider_photo/P1010159-1.jpg I used a pick to pull the piston out of the master cylinder housing. Once I alined the grove in the piston up with the hole where the the switch screws into I installed the switch. If you don't get the grove alined your warning light on the dash will be on.
http://i430.photobucket.com/albums/qq28/mountainrider_photo/P1010162.jpg
When you have the piston out there is a sheetmetal cap on one end remove that cap. Under the cap is what looks like a button it is a small plastic piece of tubing about 1/4 inch long with a metal dowl inside the plastic. if you remove those pieces there is a small oring inside thats where the leak is. replace that oring and the leak is fixed.This is the tools to do the job. 15/16th socket,brakerbar,pick , 14MM wrench and brakeclean.:Irule: