Brake light on

lylescott719 · April 11, 2014, 03:35 PM

Ok, so now that the weather thawed out enough, I took our beast out for a drive to do some pre "shake" down things. Since it has been sitting for the last three years, the tires had some definite flat spots which created some shaking of its own, but after a few miles it went away. The brakes I made sure that the master cylinder was topped off, and while sitting pressed the pedal many times hoping to build up pressure but it was still a soft pedal but could not find any leaks at the wheels or at the master cylinder. While driving I just kept it slow and pumped them before each stop, which it did fine. So upon backing it up into its spot in the yard, the brake pedal became like new, with firm pedal, but the brake light on the dash has now come on. Any ideas of why this has happened?

Stripe · April 11, 2014, 04:42 PM

Brake light on dash usually indicates that you have your parking brake applied.. Hm?

But if'n I were you I would check my brake fluid levels and then do a complete brake line bleed and refill.. If moisture got in the fluid system over the years it causes the fluid to be "softer". That is, if you were to put it in a cylinder it would take less pressure to move the press in one inch than if you were to use new fluid.

lylescott719 · April 11, 2014, 05:14 PM

Okay, thanks. The brake light does go out when you apply the pedal. Not sure if it makes a difference or not, but the "parking brake" on this one is attached to the transmission end. I don't know if there is a circuit or not tied into that system or not. I will do as you suggest and do a complete brake bleed. The pedal is definitely firm, not like when I began as it would go almost to the floor, now it goes maybe an inch.

Stripe · April 11, 2014, 10:12 PM

The Brake light going off when pressing the brake pedal down = not good. Not that bad but def not good.. I would definitely check the brake fluid levels.

DaveVA78Chieftain · April 11, 2014, 10:27 PM

Brake warning light used to indicate a loss of pressure in either the front or rear brake circuit. You do have to "balance" the front / rear circuits initially using a brake bleeding procedure.

From the Service manual: http://dave78chieftain.zxq.net/ControlValves.html#Combination

Dave

Stripe · April 12, 2014, 01:39 AM

Dave, I didn't want to say anything yet but wouldn't that also cause the sudden "Working" Brakes?

lylescott719 · June 05, 2014, 12:36 AM

Found out that the problem is a bad brake booster. I have posted a question on where to find a new one or other ideas for it. Since this coach has two of them, I will probably do something to both. The front booster, located in tandem closest to the front, seems to be the one not working. This one seems to be locking up the front brakes. The rear one seems to be working, but for how long?

Oz · June 05, 2014, 11:29 AM

We'll hold marking the original topic as being solved until you get this all sorted out and you're light does, in fact, go out and the brake system is go, ok?

lylescott719 · June 05, 2014, 06:22 PM

This fix may actually cause more problems once fixed as good pressure may actually cause wheel cylinders to start leaking, so it may not be fixed quite yet for sure.
I spent most of the night doing online research to replace or rebuild the boosters, and found not to many choices. I think I may have found the right one online only at Napa, Part #NBB 519241, but not sure. I sells for $248 with no core? Found info on another thread stating a company in Denver CO. rebuilding them, $178.50, and a semi private individual here in Colorado Springs that will do it for the same price(if he has the parts to do it), but I will need to take it off and bring it to him to look at. Either way I will have to put it on the financial back burner till extra money comes in.