Brake Warning Light on 84 Full size

[skinsgamer]

Is the brake warning light tied to the "low brake Switch"? What causes this warning light to come on and how do I fix it. I thought it was related to the Parking brake, but not so sure now. Also, the brake pedal has a wishing sound when pressed now, sounds like the brake boost has an air leak. Can that cause the warning light? My son is using the bronco for school and this my be a good job for his autoshop class.

 

[Broncobill78]

Probably the master cylinder. That's generally what trips the brake light & if you're hearing anything when you apply the brakes I'd suspect it even more strongly. It's bolted right there in front of you on the firewall. Could be the vacuum booster, not much more difficult to replace. When the diaphrams tear you frequently lose brake fluid into them. If the fluid level is steady I'd look to the MC, if it's going down & there aren't any puddles under the truck then it's the booster.

 

[Seabronc]

Welcome to the Zone > .

There are two switches that operate it, the parking brake switch, (most likely not the problem based on what you describe), and the pressure switch which is closed if the brakes are applied and there is a leak in the system.

Good luck,

>-

 

[skinsgamer]

I am sure the vacuum booster is bad, audible swishing vacumm sound coming from the brake pedal when just sittig there and when pressed. Swishing stops when the pedal bottoms out. Fluid is steady and no puddles. I think I'll go ahead and change both since to get the vacuum booster off I believe I have to remove the MC. Thanks for info.

BTW, what's the best manual for Bronco's. I have the Haynes, but it's a little weak in a lot of areas.

I've owned this Bronco since 1990 and she's my baby. My oldest boy drove here through high school now my next is in the drivers seat. I want to make sure it's safe and I also have them help with all maintenance so they gain an appreciation for taking care of her. 4 wheeling in the desert's fun (I know), but you brake,you fix it.

Anyway, I'll let you know how the fix goes!

Thanks