light under key switch

[Old Rookie]

There is a light, red on my 71, and i thought red on my 69 bronco, I never thought they worked but the 69 light has come on? Anyone know what that light is telling me?

 

[Tiko433]

It's a brake warning light . I would check the fluid. If the fluid is good , tap on the proportioning valve maybe the internal switch got stuck. The proportioning valve should have two wires connected to it. I'm not sure if the light comes on when you turn the key to ING hot or not . Mine is disconnected.

 

[Old Rookie]

I had the breaks worked on, I didn't like the adjustment, I adjusted the peddle up. I also tightened the parking break. The light comes on after the engine is running not with the key in the acc. position. I will double check the fluid but i'm pretty sure it as full as it can be.

Could i have the parking break to tight? I catches very high.

 

[Tiko433]

Not sure if it comes on when parking brakes are set. Like I said mine was not hooked up on my 74 and hadn't bothered to hook it back up. I always thought the light was a low fluid indicator. I would suspect a little air got in the proportioning valve triggering the switch. I would bleed the brakes and give the valve a little tap while doing so.

 

[Old Rookie]

Fluid was down maybe a 1/4 inch. It is topped off now and light is still on.
I was sure it didn't come on until engine was running but when i topped the fluid off and checked it the light did come on when the key was in the "on" position and running but not in the acc. position.

 

[Tiko433]

I still suspect internal switch in proportioning valve

 

[Steve83]

There is no brake fluid level sensor in an eB. Click this & look at the Right side:


https://www.supermotors.net/registry/media/874060_1 (for phone apps)

If you think it's the brake warning, unplug the proportioning valve & see if it goes out. If it does, follow the procedure to re-center the pro valve, or take it back to the shop that did the work & have them re-check their work & re-center it for you. If the light didn't come on for several miles after they worked on it, it could be ACCURATELY indicating that there's a problem in the hydraulic system that they might have caused or overlooked.

 

[broncnaz]

Its supposed to light up during start up then go off but may not always come on that's just a self test. As was said its most likely the switch on the Hblock down on the drivers side frame rail just ahead of the MC. there should be purple wires going to it.
You may still have air in one side of the brake system which would allow the spool to go to that side and cause the light to come on. or sometimes the spool just gets stuck. Sometimes you can get it to recenter by just stomping the brake pedal real hard. Or you may need to rebleed the brakes. Usually I find that it is stuck to the rear brake side so if you crack a front brake bleeder and push down the brake pedal it may recenter.
In the end its only a idiot light and means little in the overall scheme of things as you'll usually find out that your brakes are not working right before the light comes on. So if the brakes are working properly but you still get the light you could just unplug it at the switch and run without it.
Ive had one hblock that the spool jammed so tight I couldn't get it to unstick tried almost everything drilled the end of the spool so I could get a bolt in it to have something to pull on and still couldn't budge it.

 

[DirtDonk]

Same here. I've worked on several, and 904Bronco is dealing with one now too, where you just could not push the shuttle valve/piston thingy in any way that it would keep itself centered. And that was only if you could actually move it in the first place!

So good luck with yours Old Rookie. They're fun, but it's not always an insurmountable problem.
Many of us would like to convert it to a parking brake warning light instead. And some have.

Paul

 

[oldiron]

I've always been told that the light your talking about is called the "overbudget indicator"....sorry couldn't help it.;D
Greg

 

[WRG]

Sometimes this light gets converted to work as an Emergency Brake light......illuminating when EB is on and switch is on.

 

[Tiko433]

I've always been told that the light your talking about is called the "overbudget indicator"....sorry couldn't help it.;D
Greg

Hahahaha
I guess that's why mine was unhooked , so my wife couldn't see it .

 

[hyghlndr]

I would suggest actually fixing the problem %)

 

[Steve83]

The part that moves is inside. It can't be drilled from the outside, because it would just spin. So IDK what anyone is talking about putting a bolt into. If you drill into the block, it's ruined, even if it was stuck, and you get it moving again.

Drilling is pointless - it was already drilled to be manufactured. If it's really stuck (which I doubt), then just disassemble it.

This is what the '80-86 block looks like:


https://www.supermotors.net/registry/media/932180 (for phone apps)

 

[DirtDonk]

The '71 would just have been the simple H-block design, prior to the proportioning style valve in Steve's picture. But it still uses the same style switch it looks like. Aftermarket ones now have a single post switch, rather than the dual post of the factory.

Screwing something into the switch hole to help re-center the piston might make sense, but I would hate to see metal shavings get even into that isolated little pocket in the piston's notched area.
They sell tools for doing that, but I think they are made of plastic too, and are more for holding the piston in the center while you go about your business bleeding the brakes and such. Not sure it could handle being used to re-center a recalcitrant piston.

It's more work, but you can remove the block from the frame, remove the end cap and remove the piston from the block. Clean it up and re-install in it's centered position to be held in place by some tool or another.
Then when things are all buttoned up and working, reinstall the switch and wiring.
And then pray!

Paul

 

[Rickb1b]

I've fought with these switches my whole life and they never seem to work right. Now I install a push button switch behind the emergency brake lever and wire it through 12 volts to the light. Get the kind of switch that is open circuit when depressed, then install it so the brake lever opens it when released. Much better use of that light.

 

[Rustytruck]

I had a stuck valve once and had to remove the assembly bolt/plug and use hydraulic pressure to blow out the inner spool valve. Its all brass and o-ring inside. Clean the parts and put it back together. Get yourself a centering plug before you work on the system and you can avoid some of these problems. If your switch has moved off center you have a miss-matched pressure in the brake system. Once you get the problem fixed you have to pump the brakes to build up pressure and while pumped up press the pedal really hard and hold it for a while. The switch should recenter on its own if it isn't stuck. Sometimes it takes a few tries. If it doesn't recenter after half a dozen times you still have something off kilter. Make sure the rear shoes are properly set and not too far from the drums.