my brake warning light will not go off no matter what i do. Recently i changed my proportional valve and i bled the brakes. Now my brake warning light wont go off and i have NO back brakes at all. I searched and i found that maybe the little plug was dirty or not all the way in, so i cleaned that up real good, and my car still has no back brakes and the brake light wont go off. What else is there to do??

 

Have you checked the parking brake switch? As far as the back brakes...hmm. Metering valve may be plugged up...? I dunno if that is a good guess or not. You may want to check your shoe-to-drum clearance and make sure that all of the parts in the drum are working properly. (Assuming that you have rear drum brakes)

 

as dumb as this may sound,, where would i find the parking brake switch at? and i have disc brakes in the rear

 

It's right down around the base of the handle for your e-brake I believe.

 

If it's not your e-brake switch, it could be that your pressure differeential switch is grounded somewhere causing the light to come on. Check for voltage at the pressure switch with a volt meter..it should read around 12 volts. If not, it's grounded somwhere.

If that's all peachy, bleed yur brakes. That's prolly why you don't have any rears.

 

It sounds to me like you have triggered the safety device in your master cylinder.
This device transfers all braking to either the front or rear in the event of catastrophic failure (read blown brake line) to the opposite end). That way, you retain stopping power even when you blow a wheel cylinder.
The way to fix YOUR problem (ie no back brakes) is to rebleed the front...while you are doing it, have the ignition ON to reveal the brake light "ON"...have a friend monitor the light while you bleed it. As soon as the light goes off you have reset the valve...STOP BLEEDING NOW.
That should fix both your problems...brakes at both ends, and brake light out.

 

there is also a reset button on your portioning valve. its very small, and black i believe. in the front. clearly visable if looking for it. i wish i had a camera i would show u. sry

 

Did you get air into the master cylinder at all when you changed the prop valve? What was the reason for changing the prop valve? If air got into the m/c it's a pain in the butt to get it all out. If you don't have a pressure bleeder, and don't want to buy one (see http://www.brakebleeder.com and http://www.toolparadise.com for a cheaper price on it) then bring it to a tire/suspension/brakes joint and ask for a pressure bleed. Try to avoid "generic" places like autozone or pep boys or sears or midas or etc...

 

I changed my rear. it used to be drum brakes and the new rear is disc brakes. I am pretty sure i didnt get any air in the master cylinder because i checked constantly at the fluid level in the resevoir to make sure it didnt get below the "low" line. I am going to try bleeding the front brakes today which was mentioned today, when i get off of work. If that doesnt work, then i guess i will have no choice but to bleed the master cylinder.

 

Ok, i just did exactly what you said, i bled the front brakes with the ignition switch on, the the brake light did go off when i bled the front, but then when the brake was applied again, the light came back on. i dont know if this will help any, but if i pump the brakes like 10 tens and hold it, the light turns off. Please please tell me you know whats wrong. thanks in advance.

-Ian

 

According to my trusty manual, the following can result in the light coming on...
Leaks in the system (I assume you have already checked)
Air in system
Automatic adjuster problem
Restricted brake fluid passage (read kinked line)
Metering valve problem
Proportioning valve problem

You mentioned you had drums and switched to disk...I don't know if the proportioning valve is different on the two systems.
I do know that with drum brakes, the valve makes allowance for pressure required to overcome pressure required to overcome the spring pressure and lining travel on drum brakes.

Maybe someone who has done the swap can offer better advice.

 

That's cool that you know you didn't get any air in the m/c! I changed my m/c out when I put rear discs on (thought I had to change it to the J65 option (82-88 rear discs), found out later that I didn't have to, just the prop valve- damn!), and fought that thing for weeks trying to get air out.

If you can, try this. Find a plug that fits the outlet on the prop valve for the rear brake (forward-most port toward front of bumper). It'll be a pain because it's metric and not many shops (by me) have metric brass plugs. Anyway... leave the two front lines hooked up. Now try the brakes.

What this'd do is, if you have any air in the rear system, this eliminates the rear system from the "problem". If your brake light goes out and stays out, you know there's air back there somewhere. If the light acts the same, you know there's air in either the m/c or prop valve.

If you have an air compressor you can make a pressure bleeder. Get a big bottle of brake fluid. Get some vinyl tube (sold near windhsield washer tubing). Get a pack of 20 grommets for $1.99 at Radio Shack. Drill two holes into the brake fluid bottle's cap- one large enough to take a quick-disconnect fitting for your air compressor's coupler, one small enough to take the tube AND a rubber grommet. The holes will be very close to each other, so be careful when you drill. Then screw the cap back on; you'll have to remove the foam washer they usually put inside the brake fluid cap.

Hook the air hose up to the bottle of brake fluid. If you have one, put an air filter on the air hose (near the compressor end). Be careful you don't tip the bottle over (don't ask how I know this)... you don't want brake fluid going into your air hose! When you pressureize the bottle, brake fluid will come out of the vinyl tube. Use a conical adapter (found in one-man-brake-bleeder kits) to adapt the vinyl tube to the steel brake line.

Now you can purge air out of the rear system without touching a brake pedal!