HELP Break Problems - The 1947 - Present Chevrolet & GMC Truck Message Board Network

HotRod929 · 09-09-2002, 01:00 AM

Well my breaks have been working perfectly. But the other day when I was coming down this hill that I allways go down I was applying the breaks slowly to come to a stop at the bottem. But all of a sudden my break peadel dropped about an inch or two and my break light came on on the dash and I had to push really hard to get the truck to stop. That was the first time it happened. Then when I was backing up to park and was applying the brakes slowly again the brake light came on again and I had to push harder to get it to stop. If I hit the breaks really hard it will lock up no problem. Its kinda scary to me and I hope its an easy fix. I was thinking it might be a bubble in the break line but how would it get in. It never did this before. Please help. BTW I have 4 wheel drums. Thanks

HotRod

Longhorn Man · 09-09-2002, 01:08 AM

Start by checkin the fluid level...then if it still actin up...bleed the brakes.

*Fast68Chevy* · 09-09-2002, 04:04 AM

sounds like something blew, check under truck at all the drums to see if any fluid is leaking out from inside of any, and check all along frame rail back to the axle, and check all the wheel cylinder hoses too

*Zkast* · 09-09-2002, 08:33 AM

Double check for leaks.. then checka again. If you find nothing then chances are you have a master cylinder bleeding off internaly or leaking into the brake booster.

Most master cylinders will have that same characteristic. Push slowly and the fliud bypasses the seals inside the MC. Push hard and it expands the seals causing it to hold.

HotRod929 · 09-09-2002, 08:56 AM

I looked for leaks but I didnt see any but ill look again. Do you just cheak the break fluid on the master cylinder on that big ugly thing on the right of the engine? How will i know if its full or no? It looks like a cap with that wire thingy holding it down.

Zkast - Would a problem like you describe come up so suddenly since the breakes were perfect before?

THanks

HotRod

HotRod929 · 09-09-2002, 04:28 PM

ttt

HotRod929 · 09-09-2002, 05:22 PM

Ok...I checked the break reservour and it was pritty much all full. Checked the lines thoroughly and didnt see much. The soft rubber line that goes to the two rear drums could probably be replaced but no leaks. Now what do I do. It still does this. Do I need a new master cylinder? Thanks

HotRod

Stout72 · 09-09-2002, 06:34 PM

Pressure-wise, something let go in either your front or rear brake system. The brake light on your dash is wired to your proportioning valve, and alerts you to a problem with one of the systems. If a line or a hose let go, the brake fluid leak would be obvious. If you don't have brake fluid all over the place, then chances are you have air in the system or your master cylinder is leaking internally.

Bleed the brakes. Don't let the master cylinder run dry.

You can also check for air entrained in the master cylinder by having a friend SLOWLY press the brake pedal to the floor while you observe what's going on inside the master cylinder bowls. With the cover removed, you should see two little geysers appear, one in each bowl, when the pedal is depressed. No geysers = no flow = replace your master cylinder. If you get tiny bubbles, you could be sucking air from somewhere. Try bleeding the master cylinder, spend some time with it, it takes a while. Then gravity bleed both systems until you get good flow of brake fluid thru the bleeders. Good Luck.

09-09-2002, 01:00 AM	#1
HotRod929 Registered User Join Date: Mar 2002 Location: Bondurant, IA but in Worcester, MA for school Posts: 767	HELP Break Problems Well my breaks have been working perfectly. But the other day when I was coming down this hill that I allways go down I was applying the breaks slowly to come to a stop at the bottem. But all of a sudden my break peadel dropped about an inch or two and my break light came on on the dash and I had to push really hard to get the truck to stop. That was the first time it happened. Then when I was backing up to park and was applying the brakes slowly again the brake light came on again and I had to push harder to get it to stop. If I hit the breaks really hard it will lock up no problem. Its kinda scary to me and I hope its an easy fix. I was thinking it might be a bubble in the break line but how would it get in. It never did this before. Please help. BTW I have 4 wheel drums. Thanks HotRod __________________ 1970 Chevy C-20 350 V-8 Turbo 350 w/ shift kit Dana 60 w/ 4.10 gears AND Powr-Loc POSI New Additions: Summit Headers 135amp alternator Proform HEI Edelbrock 1406 600cfm carb Sunpro Tach Powr-Loc POSI Edelbrock Performer RPM Intake MSD 6A Ignition Box AIM: HotRod929 Visit My Site: http://1970chevy.netfirms.com/

09-09-2002, 08:56 AM	#5
HotRod929 Registered User Join Date: Mar 2002 Location: Bondurant, IA but in Worcester, MA for school Posts: 767	I looked for leaks but I didnt see any but ill look again. Do you just cheak the break fluid on the master cylinder on that big ugly thing on the right of the engine? How will i know if its full or no? It looks like a cap with that wire thingy holding it down. Zkast - Would a problem like you describe come up so suddenly since the breakes were perfect before? THanks HotRod __________________ 1970 Chevy C-20 350 V-8 Turbo 350 w/ shift kit Dana 60 w/ 4.10 gears AND Powr-Loc POSI New Additions: Summit Headers 135amp alternator Proform HEI Edelbrock 1406 600cfm carb Sunpro Tach Powr-Loc POSI Edelbrock Performer RPM Intake MSD 6A Ignition Box AIM: HotRod929 Visit My Site: http://1970chevy.netfirms.com/

09-09-2002, 04:28 PM	#6
HotRod929 Registered User Join Date: Mar 2002 Location: Bondurant, IA but in Worcester, MA for school Posts: 767	ttt __________________ 1970 Chevy C-20 350 V-8 Turbo 350 w/ shift kit Dana 60 w/ 4.10 gears AND Powr-Loc POSI New Additions: Summit Headers 135amp alternator Proform HEI Edelbrock 1406 600cfm carb Sunpro Tach Powr-Loc POSI Edelbrock Performer RPM Intake MSD 6A Ignition Box AIM: HotRod929 Visit My Site: http://1970chevy.netfirms.com/

09-09-2002, 05:22 PM	#7
HotRod929 Registered User Join Date: Mar 2002 Location: Bondurant, IA but in Worcester, MA for school Posts: 767	Ok...I checked the break reservour and it was pritty much all full. Checked the lines thoroughly and didnt see much. The soft rubber line that goes to the two rear drums could probably be replaced but no leaks. Now what do I do. It still does this. Do I need a new master cylinder? Thanks HotRod __________________ 1970 Chevy C-20 350 V-8 Turbo 350 w/ shift kit Dana 60 w/ 4.10 gears AND Powr-Loc POSI New Additions: Summit Headers 135amp alternator Proform HEI Edelbrock 1406 600cfm carb Sunpro Tach Powr-Loc POSI Edelbrock Performer RPM Intake MSD 6A Ignition Box AIM: HotRod929 Visit My Site: http://1970chevy.netfirms.com/

09-09-2002, 06:34 PM	#8
Stout72 Not my good side. Join Date: Mar 2002 Location: Fairfield, California Posts: 222	Pressure-wise, something let go in either your front or rear brake system. The brake light on your dash is wired to your proportioning valve, and alerts you to a problem with one of the systems. If a line or a hose let go, the brake fluid leak would be obvious. If you don't have brake fluid all over the place, then chances are you have air in the system or your master cylinder is leaking internally. Bleed the brakes. Don't let the master cylinder run dry. You can also check for air entrained in the master cylinder by having a friend SLOWLY press the brake pedal to the floor while you observe what's going on inside the master cylinder bowls. With the cover removed, you should see two little geysers appear, one in each bowl, when the pedal is depressed. No geysers = no flow = replace your master cylinder. If you get tiny bubbles, you could be sucking air from somewhere. Try bleeding the master cylinder, spend some time with it, it takes a while. Then gravity bleed both systems until you get good flow of brake fluid thru the bleeders. Good Luck. __________________ 72 Chevy K20 Custom Camper, 350/350, 4" lift, dual shock suspension front & rear. Daily driver and a work in progress. 00 Suburban LT 90 Camaro RS 79 Yamaha XS1100 Special (Ol' Reliable)

09-09-2002, 01:08 AM	#2
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Start by checkin the fluid level...then if it still actin up...bleed the brakes.

09-09-2002, 04:04 AM	#3
Fast68Chevy Account Suspended Join Date: May 2000 Location: IL Posts: 0	sounds like something blew, check under truck at all the drums to see if any fluid is leaking out from inside of any, and check all along frame rail back to the axle, and check all the wheel cylinder hoses too

09-09-2002, 08:33 AM	#4
Zkast Account Suspended Join Date: May 2002 Location: Olathe, Kansas Posts: 929	Double check for leaks.. then checka again. If you find nothing then chances are you have a master cylinder bleeding off internaly or leaking into the brake booster. Most master cylinders will have that same characteristic. Push slowly and the fliud bypasses the seals inside the MC. Push hard and it expands the seals causing it to hold.

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