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

C&C Chevy · 07-11-2005, 01:37 PM

This is for my wifes car, but I figure hydrolic brakes are hydrolic brakes, right..

The pedal goes soft(to the floor sometimes!) after the car has been driven awhile. I've bleed the brakes (4 disc) and they work fine for awhile after start-up but then go soft. What's up?? I'm thinking a weak brake line, but how do I find out??

btw, the brakes always have pressure, I'll pull up to a stop and the pedal will start losing pressure and the car will roll if I'm not careful.

SSC's76 · 07-11-2005, 02:52 PM

Well a leak some where would be a sign. What kind of car is it? Yes it makes a difference. an example would be; If it's an ABS eqquipt GM with no signs of fluid leakage then the ABS unit has a stuck valve.

hobbz · 07-11-2005, 03:21 PM

do you loose fluid in your resvior but not see any leaks? if so prolly the master cyl

C&C Chevy · 07-11-2005, 03:31 PM

It's a 93 Accord. The ABS light has always come on but I was always told that it doesn't affect the line pressure, so I never got it fix. And this just started a few weeks ago, and the ABS light has been coming on for years.

I did have the master cyl. replaced a year ago. Maybe something there??

The pedal doesn't go straight to the floor like there is air in the caliper. It just kind of eases on down. lol..

apstguy · 07-11-2005, 05:08 PM

Probably a bad master cylinder.

**old Rusty C10** · 07-11-2005, 05:51 PM

prolly a bad master cylinder.. the abs unit is different that wont make the fluid leak ... and if you put a rebuilt in there its only as good as the rebuilder and kit put in there... sometimes a new one aftermarket is almost as cheap as a rebuilt one so check that out

red86chevy · 07-11-2005, 08:23 PM

I also have a '93 Accord and I had the same problem at around 110,000 miles. The master cylinder was bad. Hope this helps.

Jeremy

C&C Chevy · 07-11-2005, 08:28 PM

Does a bad master cylinder account for the brakes not working only half the time. I was thinking maybe a brake line was getting hot, as the car warmed up, and it started to fail. ???

C&C Chevy · 07-11-2005, 08:35 PM

Thanks 86. I guess that's the problem. The car has 170,000 on it, so I'm not to worried about putting alot of $$$ into it. Probably see if they can put another used cylinder on.

red86chevy · 07-11-2005, 09:27 PM

C&C Chevy mine has rear drum not disc. I'm not sure why it would only do it when hot though. Mine just started one day and did it hot or cold. I would still bet It's the master cylinder though.

Jeremy

*Zilverado* · 07-12-2005, 05:53 PM

Hey here's an original suggestion.... Master Cylinder...

OK, so it wasn't original.

07-11-2005, 01:37 PM	#1
C&C Chevy Registered User Join Date: Feb 2003 Location: Midwest City, OK Posts: 1,001	Brake problems This is for my wifes car, but I figure hydrolic brakes are hydrolic brakes, right.. The pedal goes soft(to the floor sometimes!) after the car has been driven awhile. I've bleed the brakes (4 disc) and they work fine for awhile after start-up but then go soft. What's up?? I'm thinking a weak brake line, but how do I find out?? btw, the brakes always have pressure, I'll pull up to a stop and the pedal will start losing pressure and the car will roll if I'm not careful. __________________ Robert Current: 1986 SWB Silverado 4.3 / TH400 Past: 1985 SWB Silverado 305 / TH350 - sold 1995 1987 1/2 ton Silverado - FI 350 / 700R4 sold 2007

07-11-2005, 02:52 PM	#2
SSC's76 No No Join Date: Jun 2005 Location: Pueblo Colorado Posts: 1,781	Well a leak some where would be a sign. What kind of car is it? Yes it makes a difference. an example would be; If it's an ABS eqquipt GM with no signs of fluid leakage then the ABS unit has a stuck valve. __________________ 1976 Custom Deluxe SWB Med FMB.3/4 Drop. Gen VI 454, Muncie HD 3 speed With Modified OE Hurst Shifter, 3.73 12 bolt, GMPP HO roller cam, Hooker headers, Performer intake with modified Q-jet, Accel distributor. Best 1/4 12.3 @108. Funnest run 19.84 @88 full 1/4 mile burn out. 1997 K1500 ext cab 5.7 stock except muffler

07-11-2005, 03:31 PM	#4
C&C Chevy Registered User Join Date: Feb 2003 Location: Midwest City, OK Posts: 1,001	It's a 93 Accord. The ABS light has always come on but I was always told that it doesn't affect the line pressure, so I never got it fix. And this just started a few weeks ago, and the ABS light has been coming on for years. I did have the master cyl. replaced a year ago. Maybe something there?? The pedal doesn't go straight to the floor like there is air in the caliper. It just kind of eases on down. lol.. __________________ Robert Current: 1986 SWB Silverado 4.3 / TH400 Past: 1985 SWB Silverado 305 / TH350 - sold 1995 1987 1/2 ton Silverado - FI 350 / 700R4 sold 2007 Last edited by C&C Chevy; 07-11-2005 at 03:32 PM.

07-11-2005, 05:08 PM	#5
apstguy LED King Join Date: Jan 2003 Location: Sacramento, CA Posts: 2,088	Probably a bad master cylinder. __________________ Tyler 1985 C10 305 w/ Bowtie OD TH700R4 3.42 LSD 202,000 miles 2006 Ford Focus ZX3 5-speed Stick 2016 Chevy Spark EV Gone: 2002.5 VW GTI 24v VR6 Gone: 2008 VW R32

07-11-2005, 05:51 PM	#6
old Rusty C10 Robert Olson Transport Join Date: Oct 2002 Location: recent transplant to NC USA Posts: 20,277	prolly a bad master cylinder.. the abs unit is different that wont make the fluid leak ... and if you put a rebuilt in there its only as good as the rebuilder and kit put in there... sometimes a new one aftermarket is almost as cheap as a rebuilt one so check that out __________________ Bob 1951 International running on a squarebody chassis "If a man's worth is judged by the people he associates himself with, then i am the richest man in the world knowing some of the fine people of this board" http://67-72chevytrucks.com/vboard/a...t.php?f=25&a=9 (you can review the site rules here!) PM Me for your vehicle/parts hauling needs in the North East US or see my Facebook page Robert Olson Transport Live each day to the fullest.. you never know when fate is going to pull the rug out from under you... I hate cancer!!

07-11-2005, 03:21 PM	#3
hobbz Registered User Join Date: Jun 2005 Location: ashland, ky Posts: 632	do you loose fluid in your resvior but not see any leaks? if so prolly the master cyl

07-11-2005, 08:23 PM	#7
red86chevy Registered User Join Date: Jun 2005 Location: sc Posts: 77	I also have a '93 Accord and I had the same problem at around 110,000 miles. The master cylinder was bad. Hope this helps. Jeremy __________________ 86 c-10 383 w/ sportsman II heads comp 286h cam Edlbrock RPM Performer intake Holley 750 th350 w/2400 stall 3.73 gears with powertrax No-Slip posi unit. Just broken in good. Will get a 1/4 time this week.

07-11-2005, 08:28 PM	#8
C&C Chevy Registered User Join Date: Feb 2003 Location: Midwest City, OK Posts: 1,001	Does a bad master cylinder account for the brakes not working only half the time. I was thinking maybe a brake line was getting hot, as the car warmed up, and it started to fail. ??? __________________ Robert Current: 1986 SWB Silverado 4.3 / TH400 Past: 1985 SWB Silverado 305 / TH350 - sold 1995 1987 1/2 ton Silverado - FI 350 / 700R4 sold 2007

07-11-2005, 08:35 PM	#9
C&C Chevy Registered User Join Date: Feb 2003 Location: Midwest City, OK Posts: 1,001	Thanks 86. I guess that's the problem. The car has 170,000 on it, so I'm not to worried about putting alot of $$$ into it. Probably see if they can put another used cylinder on. __________________ Robert Current: 1986 SWB Silverado 4.3 / TH400 Past: 1985 SWB Silverado 305 / TH350 - sold 1995 1987 1/2 ton Silverado - FI 350 / 700R4 sold 2007

07-11-2005, 09:27 PM	#10
red86chevy Registered User Join Date: Jun 2005 Location: sc Posts: 77	C&C Chevy mine has rear drum not disc. I'm not sure why it would only do it when hot though. Mine just started one day and did it hot or cold. I would still bet It's the master cylinder though. Jeremy __________________ 86 c-10 383 w/ sportsman II heads comp 286h cam Edlbrock RPM Performer intake Holley 750 th350 w/2400 stall 3.73 gears with powertrax No-Slip posi unit. Just broken in good. Will get a 1/4 time this week.

07-12-2005, 05:53 PM	#11
Zilverado Account Suspended Join Date: Nov 2002 Location: Winnipeg, Manitoba, Canada Posts: 798	Hey here's an original suggestion.... Master Cylinder... OK, so it wasn't original. Last edited by Zilverado; 07-12-2005 at 05:54 PM.



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