Brake problem, need help - The 1947 - Present Chevrolet & GMC Truck Message Board Network

69K10 Tank · 05-10-2004, 09:43 PM

Ok, so comming home from school my brake pedal went soft and all the way to the floor, but if i pumped it again i'd get brakes. Thankfully I only live about a mile from school and this started about 3 blocks from home. So once i got home my dad and I bled all the brakes and it still happens. Basically if I dont jump on the pedal, and just push steadily it will go all the way to the floor. If I push on it really hard really quick the pedal is firm, but still slowly goes to the floor. I'm kinda thinking its the master cyinder since i don't see leaks anywhere. I just got back from shucks with a new master cylinder and i'll put it on after i get home from school tomorrow (not driving, hitching a ride with a friend). Just wondering if there might be anything else or if you all think its the master cyinder too. Thanks (sorry this is kinda long and rambling, but i kinda needed to vent)

cdowns · 05-10-2004, 10:02 PM

yep sounds like the master cyl

Willy Prost · 05-10-2004, 10:04 PM

Yes, this sounds like a classic master cylinder malfunction.

Just don't forget to bench bleed the rebuilt master cylinder before you install it on the truck. Otherwise you won't be any better off after replacing the master cylinder.

Jeepster376 · 05-10-2004, 10:16 PM

It definately sounds like the master cylinder. Since from your description the problem came on rather suddenly, it sounds like one of the piston seals in your MC may have torn or broken. I would fix it as soon as possible, because if one of those seals comes loose you could have sudden complete brake loss. Ask me how I know.

69K10 Tank · 05-10-2004, 10:19 PM

Yeah, thanks guys. I'm going to put the new master cylinder on tomorrow after I get home from school. The truck is parked and i'm not driving it till I replace it. Thanks for double checking me guys. Jeepster, I don't want to think about what a total loss of brakes would be like, just hope the e-brake is set right. Thanks again guys

Gordo · 05-11-2004, 08:18 PM

Like Willy says, don't forget to bench bleed that new master before you install it. It will save you some trouble.

69K10 Tank · 05-11-2004, 08:42 PM

Thanks for all the advise, I just got the brakes fixed. I did bench bleed the master cylinder and once I got it installed, bled the brakes. Wow, I have brakes again. I'll have to bleed the brakes again tomorrow, need to firm them up just a bit more. Thanks again guys, man, I love this place

05-10-2004, 09:43 PM	#1
69K10 Tank Registered User Join Date: Aug 2003 Location: Olypmia, Wa Posts: 49	Brake problem, need help Ok, so comming home from school my brake pedal went soft and all the way to the floor, but if i pumped it again i'd get brakes. Thankfully I only live about a mile from school and this started about 3 blocks from home. So once i got home my dad and I bled all the brakes and it still happens. Basically if I dont jump on the pedal, and just push steadily it will go all the way to the floor. If I push on it really hard really quick the pedal is firm, but still slowly goes to the floor. I'm kinda thinking its the master cyinder since i don't see leaks anywhere. I just got back from shucks with a new master cylinder and i'll put it on after i get home from school tomorrow (not driving, hitching a ride with a friend). Just wondering if there might be anything else or if you all think its the master cyinder too. Thanks (sorry this is kinda long and rambling, but i kinda needed to vent) __________________ Cry havoc and let slip the dogs of war 69 K-10, 350, sm465, T221, 33" BFG A/T, drums all around (soon to be discs)

05-10-2004, 10:02 PM	#2
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	yep sounds like the master cyl __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

05-10-2004, 10:16 PM	#4
Jeepster376 Registered User Join Date: Feb 2004 Location: Massachusetts Posts: 269	It definately sounds like the master cylinder. Since from your description the problem came on rather suddenly, it sounds like one of the piston seals in your MC may have torn or broken. I would fix it as soon as possible, because if one of those seals comes loose you could have sudden complete brake loss. Ask me how I know. __________________ 72 Cheyenne Super 4x4 SWB

05-10-2004, 10:19 PM	#5
69K10 Tank Registered User Join Date: Aug 2003 Location: Olypmia, Wa Posts: 49	Yeah, thanks guys. I'm going to put the new master cylinder on tomorrow after I get home from school. The truck is parked and i'm not driving it till I replace it. Thanks for double checking me guys. Jeepster, I don't want to think about what a total loss of brakes would be like, just hope the e-brake is set right. Thanks again guys __________________ Cry havoc and let slip the dogs of war 69 K-10, 350, sm465, T221, 33" BFG A/T, drums all around (soon to be discs)

05-11-2004, 08:18 PM	#6
Gordo Registered User Join Date: Jan 2001 Location: Killingworth, CT. USA Posts: 3,378	Like Willy says, don't forget to bench bleed that new master before you install it. It will save you some trouble. __________________ 1971 C10 swb stepside 350/700R4/3.73posi (retired as of 4/22/03) 1998 S10 short bed 2002 S10 Blazer 1942 Oldsmobile 1958 Massey Harris Pony 1951 Wife Killingworth, Connecticut May those who love us, love us, any of those who do not love us, may God turn their hearts. And if God is unable to turn their hearts, may he turn their ankles so we may know them by their limping. A man who works with his hands is a laborer; a man who works with his hands and his brain is a craftsman; but a man who works with his hands and his brain and his heart is an artist.

05-10-2004, 10:04 PM	#3
Willy Prost Senior Member Join Date: Jan 2000 Location: Arlington, VA Posts: 398	Yes, this sounds like a classic master cylinder malfunction. Just don't forget to bench bleed the rebuilt master cylinder before you install it on the truck. Otherwise you won't be any better off after replacing the master cylinder.

05-11-2004, 08:42 PM	#7
69K10 Tank Registered User Join Date: Aug 2003 Location: Olypmia, Wa Posts: 49	Thanks for all the advise, I just got the brakes fixed. I did bench bleed the master cylinder and once I got it installed, bled the brakes. Wow, I have brakes again. I'll have to bleed the brakes again tomorrow, need to firm them up just a bit more. Thanks again guys, man, I love this place __________________ Cry havoc and let slip the dogs of war 69 K-10, 350, sm465, T221, 33" BFG A/T, drums all around (soon to be discs)



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