Okay guys, a few days ago the rear axle went out on my truck...Gary Lewis provided a used axle for me. I swapped it in and got back on the road. However my rear brakes were not working. I bled the system using the old fashion system with my wife pumping. Still got nothing. So...I eventually got around last night to figuring it out. Both wheel cylinders on the axle Gary provided me were locked up. So I used my old cylinders and now they work. The brake light went off as well.

This morning on my way to the chiropractor the brake light came back on. Whats the deal with that? The rear brakes seems to be working fine.

Or is the brake light for the emergency brake? I cannot tell. Thanks for any help.

 

BTW Gary, the emergency brake cables were different lengths...I know they are supposed to be different, but Im not talking about the length of the sleeve the cable run through, I mean the length of the cable coming out of the sleeve where the sleeves mount to that bulkhead just in front of the driver's side back tire are different. I was unable to re-attach the e-brake cable because thos two cable were too different in length. I checked behind the drums to make sure the longer one wasn't stuck in the engaged position, and it wasn't. Its just longer for some reason. Was it that way when you disconnected it off the blue truck?

 

Does anybody got any idea about the light?

 

The Brake Warning light on the 1984-1986 does two functions.

One: It tells you of a emergency. Brake failure.
Two: Tells you that you left the parking brake on.

On the parking brake pedal you will find a little switch with a Purple wire attached. Unplug this wire and see if the light goes out. If it does go out, you have a problem with either; A: your parking brake cables are not adjusted to the correct tension to hold the pedal tight. B: your rear brakes are out of adjustment. C: Parking brake cables are stretched D: Rear brake pads severly worn. E: Parking brake mechanisims in drum are sticking. F: Parking Brake Cable Adjustment Equallizer, beyond it's usefull life.

If the light doesn't go out, you have a problem with the hydraulic system. Check the wheel cylinders for leaks, check the master cylinder for proper fluid level. Bleed the brakes again etc...

 

Hey, thanks alot! I will do this in a minute. i am getting ready to leave from work. I am pretty sure the hydraulic system is working fine. How tight should I adjust the drum brakes? Should there be a little bit of drag on the pads or should there be a little slop?

 

Is this also the same for an 82 my brake light is also on and I haven't had time to trace it out.

 

okay. didn't have time to mess with this much. I did take the purple wire off the e-brake assembly under the dash. The light went off momentarily then came back on. I adjusted the drum shoes tight, then backed off a turn of the adjuster. Light is still on. I had the drums off two nights ago and I watched the brake pads move while my wife pushed on the brake. So I know the wheel cylinders are working.....im a bit stumbled now...anyone have a clue why the light is still on? Should I try to reset by disconnecting the battery or something?

 

Just to verify what's causing it, follow the lines down from the brake master cylinder, and you should run into a block called the proportioning valve. There will be a single wire on it also. Take this wire off and see if the light goes out. If it does, then that's the problem with the light.

The proportioning valve has a front brake section and a rear brake section. The only thing that separates these sections inside the valve is a plunger. If one section loses brakes and the other doesn't, pressure from the good side will push the plunger off center, and then it will touch and ground out the wire and turn the brake warning light on. If your brakes are good, you just need to re-center the plunger.

If we can assume you lost pressure in the rear brakes, then it pushed the plunger toward the rear section. Since the rear is good now, what I would do is open a front bleeder and get your wife to stomp on the brakes hard and hold them down while you stand back from the caliper, and then while she is holding it down, tighten the front bleeder back up. This theoretically will let the good pressure from the rear brakes push the plunger back to where it belongs(hopefully it won't go too far the other way).

 

I will give that a try as soon as i get the chance. Thanks alot!

 

I pulled the plug off the proportioning valve. It had a single plug with two wires, not one wire. Anyways...that turned the light off. Shouldn't there be equal pressure in both the front and rear hydraulic circuits? If that is so, then the plunger you speak of should center itself. Maybe I do still have some air in the rear brakes?? I dunno. Im so sick and tired of everything breaking down on me right now. I keep struggling and can't seem to get ahead.

 

!982 doesn't have the switch in the brake pedal, so the light being on can't be caused by that.

Investigate your brake system.

 

1980-1983 the Brake warning light warns of hydraulic brake failure only.

As CTBUTIS stated check your brake system.


Yes, there should be equal pressure in both front and rear brake hydraulics. Try reseting the porportioning valve if you haven't done so already.