FOR PLA

Centering the pressure bias piston should be the last step. Move it to center with small screwdriver and replace switch. Job done.

WVZR-1

That's what I thought likely. Did you set the E-brake before starting the project? Maybe check? Maybe disconnect the switch at the E-brake and test?


I understand the "SHOULD BE" for sure.

FOR PLA

I am assuming bleeding at each wheel caliper was done properly. Then move the pressure switch to center.

LarryShivers

I have repositioned the piston two times with the same results. Light goes off but once brakes are applied the light is back on.

FOR PLA

Rebleed each caliper in proper order then reset bias switch. You have air in system some where.

LarryShivers

Will start back on these next week. Leaving town for several days tomorrow morning. Thanks to everyone for your advise. I'll update next week.

Cliff Harris

The last time I bled my brakes I got the BRAKE light. It went out after I pressed the brake pedal down firmly as far as it would go.

WVZR-1

...that is precisely what the FSM mentions needs to happen.

LarryShivers

Got a vacuum pump bleeder from Harbor Freight and bled all wheels again. Got a better pedal of brakes but the light is still on. One possible problem I did see was that the right front when bled took a long time to get fluid to flowing. The rest of the wheels filled up the pump container with fluid rather quickly with the vacuum pump pressure declining slowly. The RF pump pressure went down quickly with very little fluid flow. I have never had any problems with the brakes pulling either way but this fluid flow is confusing.

Also are there any other bleeder besides the 4 wheels?

antfarmer2

Sounds like your rubber line is swelled up constricting the flow might be time to change them. Any sign of leaks?

LarryShivers

Will check today. Strange though since there wasn't a problem before I changed the Master Cylinder.

LarryShivers

Bleeder was bad. Swapped the left and right bleeders and vacuum bled the right side. Vacuum pressure went down slowly and fluid quickly drained into the container. I repositioned the piston and the light was off until I applied the brakes. Is there anyway to check to see if I have a bad MC? I don't know what else to try except bleed the whole system again.

antfarmer2

Need a new bleeder I would think you got some air in there swapping them.

LarryShivers

Replaced the bleeder and vacuum bled all wheels again. Repositioned the piston and light is off until brakes are applied. I also bled each wheel manually with someone pumping the brakes. No air.
One thing new I did see. I have all 4 wheels off the car - makes for easier bleeding. I cranked the car and put it in drive. The front wheels locked down but the rear wheel will not lock down unless you really stand on the brakes.
Evidently I have unequal pressure between the front and the back but what is causing it? MC has been bled twice. All wheels have been bled at least 5 times.
Could it be the proportioning value in the MC causing the problem? If so how would you check it?
This is a new Cardone Select MC from Rock Auto.

antfarmer2

The front wheels need to be turning for the brakes to work right. Does the piston move off place each time the light comes on?

LarryShivers

Yes. Every time I have checked it (4 or 5 times) the piston is off center.

JrRifleCoach

BINGO!

Pull the switch and look into the hole. The shuttle piston has a ring groove that should be centered. The switch has a small pin that rests in this groove. If the shuttle moves from a drop of pressure on one side the shuttle pushes up on the switch. If the o-rings on this shuttle leak. Fluid comes out of the switch.

JrRifleCoach

You can move the shuttle with a small flat screw driver tip.

antfarmer2

Looks like the problem is found! I have never personally messed with one. Hope someone can tell you why.

LarryShivers

I have removed the switch several time and manually moved the piston grove to the center. Light goes off until brake pedal is pressed. Why does it keep moving? There is no brake fluid in the switch cavity. What can I do that I haven't already tried?
Another MC??