Brake help please - The 1947 - Present Chevrolet & GMC Truck Message Board Network

ChevyDude · 08-19-2003, 11:55 AM

My dash brake warning light stays lit most of the time but goes out now and then. My brakes work fine and I don't know whats up. The brown wire IS connected to the proportioining valve. Truck is a 72 K-10. any help is appreciated.

tom hand · 08-19-2003, 12:11 PM

On my 72 the brown wire is also connected to a switch on the parking brake so you don't drive around with it on...so the light serves two funtions. Crawl under the dash and check it out.

Longhorn Man · 08-19-2003, 04:15 PM

*note to everyone else* The parking brake light is a feature on only the 72. (possably the 71 also)
Chevy dude, if the parking brake pedal is up all the way, and the wire is properly connected, unplug it and see if the light goes out. If it does, the switch on the pedal is bad. If it stays on, then unplug the one on the master cylinder. If the light goes out, the problem is in the prop valve. If it is still on, you need to start following the wires (both the one from the prop valve,a nd the one from the E-brake pedal) and look for a place that it is grounded out.

ChevyDude · 08-19-2003, 04:33 PM

Thank you so much Longhornmail, your responce will help me 100%. I did look all over the e brake and could not find a wire going to it. Where should the wire be connect on the e brake. Any one got a pic?

Thanks guys!

miket · 08-19-2003, 07:38 PM

Sorry guys I am slow today (and sometimes other days!) but what purpose does the brown wire serve running to the proportioning valve?

Also are these things adjustable and do they go bad? If so what do they cost?

Longhorn Man · 08-19-2003, 11:09 PM

It turns on the dash warning light to allert you of a hyd. imballance.
Basicly, if it comes on...pull over and confirm your brakes still work and check your fluid. If you know how to work on the brake system, then check it out. If you don't, get a tow truck.
Chevy Dude, honistly, i have never seen one hooked to the E-brake pedal...I am going by what a few ppl here have said. I have no reason to say they don't know whats up...they have 72's, and I don't.

Class of 69 · 08-19-2003, 11:29 PM

When I worked in a repair facility, we some times had the light come on after brake work too. To recenter the piston in the valve, and get the light to go out, one guy would crack the brake line loose after the valve and another would LIGHTLY press the pedal to bleed off some fluid. If the first line didn't fix it, crack the other. The lower pressure on one side of the valve would always center the piston, and the light would go out.

miket · 08-19-2003, 11:33 PM

Just to sort of continue...

my pedal is very hard...in fact my brakes are easier in my Chevelle (which doesn't have power brakes)) than in my truck. I get 12-13 inches of VAC at idle...booster is new....but I think the fluid might have gotten cooked....brake line against a header...I don't know when the master was replaced if ever...brakes work but they don't seemed to be proportioned correctly.

Where should I start? New Master Cyl then valve maybe if it doesn't fix it?

Longhorn Man · 08-20-2003, 12:03 AM

If your brake fluid is cooked, flush it. It is worthless.
Then get that line at least one inch away from the header.

Fire up the truck, and use vicegrips and pinch the hose going to the brake booster. Get in and apply the brakes a few times. If the brake pedal does not get harder, then you need a new booster.

miket · 08-20-2003, 12:05 AM

I don't know why I didn't think of that......thanks Longhorn!

08-19-2003, 11:55 AM	#1
ChevyDude Senior Member Join Date: Jun 2003 Location: Westminster, CO Posts: 3,071	Brake help please My dash brake warning light stays lit most of the time but goes out now and then. My brakes work fine and I don't know whats up. The brown wire IS connected to the proportioining valve. Truck is a 72 K-10. any help is appreciated. __________________ Alex 1971 Lil' Red 350 SBC 700R4

08-19-2003, 12:11 PM	#2
tom hand CCRider Join Date: Feb 2000 Location: Olive Branch,MS,USA Posts: 2,232	On my 72 the brown wire is also connected to a switch on the parking brake so you don't drive around with it on...so the light serves two funtions. Crawl under the dash and check it out. __________________ 72 GMC Sierra SWB almost finished---- 84 Softail Olive Branch MS

08-19-2003, 04:33 PM	#4
ChevyDude Senior Member Join Date: Jun 2003 Location: Westminster, CO Posts: 3,071	Thank you so much Longhornmail, your responce will help me 100%. I did look all over the e brake and could not find a wire going to it. Where should the wire be connect on the e brake. Any one got a pic? Thanks guys! __________________ Alex 1971 Lil' Red 350 SBC 700R4

08-19-2003, 07:38 PM	#5
miket Registered User Join Date: Jan 2003 Location: Seattle WA Posts: 1,466	Sorry guys I am slow today (and sometimes other days!) but what purpose does the brown wire serve running to the proportioning valve? Also are these things adjustable and do they go bad? If so what do they cost? __________________ FocuzTech Performance Evergreen Protective Coatings Gatorhyde...the best kept secret in spray in bed lining & protection

08-19-2003, 11:29 PM	#7
Class of 69 Registered User Join Date: Mar 2003 Location: Stillwater MN Posts: 1,166	When I worked in a repair facility, we some times had the light come on after brake work too. To recenter the piston in the valve, and get the light to go out, one guy would crack the brake line loose after the valve and another would LIGHTLY press the pedal to bleed off some fluid. If the first line didn't fix it, crack the other. The lower pressure on one side of the valve would always center the piston, and the light would go out. __________________ 69 GMC K10 ..some restoration required....still..

08-19-2003, 04:15 PM	#3
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	note to everyone else The parking brake light is a feature on only the 72. (possably the 71 also) Chevy dude, if the parking brake pedal is up all the way, and the wire is properly connected, unplug it and see if the light goes out. If it does, the switch on the pedal is bad. If it stays on, then unplug the one on the master cylinder. If the light goes out, the problem is in the prop valve. If it is still on, you need to start following the wires (both the one from the prop valve,a nd the one from the E-brake pedal) and look for a place that it is grounded out.

08-19-2003, 11:09 PM	#6
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	It turns on the dash warning light to allert you of a hyd. imballance. Basicly, if it comes on...pull over and confirm your brakes still work and check your fluid. If you know how to work on the brake system, then check it out. If you don't, get a tow truck. Chevy Dude, honistly, i have never seen one hooked to the E-brake pedal...I am going by what a few ppl here have said. I have no reason to say they don't know whats up...they have 72's, and I don't.

08-19-2003, 11:33 PM	#8
miket Registered User Join Date: Jan 2003 Location: Seattle WA Posts: 1,466	Just to sort of continue... my pedal is very hard...in fact my brakes are easier in my Chevelle (which doesn't have power brakes)) than in my truck. I get 12-13 inches of VAC at idle...booster is new....but I think the fluid might have gotten cooked....brake line against a header...I don't know when the master was replaced if ever...brakes work but they don't seemed to be proportioned correctly. Where should I start? New Master Cyl then valve maybe if it doesn't fix it? __________________ FocuzTech Performance Evergreen Protective Coatings Gatorhyde...the best kept secret in spray in bed lining & protection

08-20-2003, 12:03 AM	#9
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	If your brake fluid is cooked, flush it. It is worthless. Then get that line at least one inch away from the header. Fire up the truck, and use vicegrips and pinch the hose going to the brake booster. Get in and apply the brakes a few times. If the brake pedal does not get harder, then you need a new booster.

08-20-2003, 12:05 AM	#10
miket Registered User Join Date: Jan 2003 Location: Seattle WA Posts: 1,466	I don't know why I didn't think of that......thanks Longhorn! __________________ FocuzTech Performance Evergreen Protective Coatings Gatorhyde...the best kept secret in spray in bed lining & protection



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