Bad Brake Booster? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

EyeH8the24 · 04-28-2008, 01:48 AM

when i crank my truck my pedal gets sucked to the floor and wont come back up ,itlocs the brakes down,if i take vacum line off it doesnt do this .i have had bad boosters before but never had this problem ...any input?

69halfton · 04-28-2008, 02:03 AM

...sounds kind-of weird to me. but it unplugging the booster from the vacuum makes it better, then thats what i would say the problem is.

EyeH8the24 · 04-28-2008, 02:05 AM

yeah i have never seen one pull the pedal to the floor and lock the brakes down...

**leddzepp** · 04-28-2008, 02:06 AM

Usually a bad booster causes the brake pedal to be difficult to depress...not vice-versa. But if disconnecting the vacuum line solves it, then it must be the booster.

Sinister · 04-28-2008, 02:23 AM

Could it possibly be the check valve?

EyeH8the24 · 04-28-2008, 02:27 AM

is the check valve internal?

**leddzepp** · 04-28-2008, 02:28 AM

Hmmm...maybe the check valve is shot, and allowing TOO much vacuum to be pulled on the booster?? This sounds very reasonable to me, and a heck of a lot cheaper to fix!

dieselarmy13 · 04-28-2008, 02:31 AM

The ckeck valve is the plastic thingy that your vacuum line hooks onto on the booster.

**leddzepp** · 04-28-2008, 02:32 AM

The check valve is the plastic piece that the vacuum line connects to on the outside of the booster.

EyeH8the24 · 04-28-2008, 02:33 AM

will try another check vale tomm then hope thats it ,it was working right one day ...get in it the next and was saying wth!

PanelDeland · 04-28-2008, 03:14 AM

???? Did you just replace something.I ask because I am wondering if maybe the pedal is slightly depressed causing the booster/brakes to activate.The brake light switch or the rod out of adjustment? Just some other things to check.

EyeH8the24 · 04-28-2008, 04:51 AM

i put the booster set up on a couple of months ago..and have driven the truck only around the shop as i was installing new engine and new 700r trans as well as swapping rearends..but it worked great till today.

67_C-30 · 04-28-2008, 05:27 AM

Are you going to be at Mike's tomorrow?

Longhorn Man · 04-28-2008, 06:28 AM

the check valve doesn't limit the vacume applied, it prevents the vacume from escaping.
It's a new one by me... but it about has to be the booster.

**leddzepp** · 04-28-2008, 09:21 AM

yeah, i know it's purpose is to prevent it from escaping, but it's worth a shot as weird as this problem is!!

bigblockorange · 04-28-2008, 11:27 AM

I had a similar problem with a pedal sticking I had to take apart my bracket and lever from behind my booster. I blasted all the parts painted them and never seized them. I then used seal grease and lubed the plunger shaft that is under the boot facing the firewall. This took care of my sticking problem. Good luck

EyeH8the24 · 04-28-2008, 08:25 PM

67-c30...i was goin to mikes but my kids had different plans for me ..lol

67_C-30 · 04-29-2008, 12:39 AM

Quote:

Originally Posted by EyeH8the24

67-c30...i was goin to mikes but my kids had different plans for me ..lol

I know how that goes!

Longhorn Man · 04-29-2008, 01:26 AM

bigblockorange, if you were to re-read the actual problem, you'll see that the pedal is not actually sticking, but getting sucked to the floor.

04-28-2008, 01:48 AM	#1
EyeH8the24 Registered User Join Date: Dec 2004 Location: beulah,alabama Posts: 1,075	Bad Brake Booster? when i crank my truck my pedal gets sucked to the floor and wont come back up ,itlocs the brakes down,if i take vacum line off it doesnt do this .i have had bad boosters before but never had this problem ...any input?

04-28-2008, 02:03 AM	#2
69halfton Registered User Join Date: Apr 2007 Location: King City, Ontario, Canada Posts: 974	Re: Bad Brake Booster? ...sounds kind-of weird to me. but it unplugging the booster from the vacuum makes it better, then thats what i would say the problem is. __________________ - Jason If you can turn, Youre not going fast enough. Favorite caption: first car to 200 mph in the 1/4 mile, no parachute, drum brakes all the way around.. ..back when men were men.

04-28-2008, 02:05 AM	#3
EyeH8the24 Registered User Join Date: Dec 2004 Location: beulah,alabama Posts: 1,075	Re: Bad Brake Booster? yeah i have never seen one pull the pedal to the floor and lock the brakes down...

04-28-2008, 02:06 AM	#4
leddzepp Moderator Join Date: May 2007 Location: Southern Cal Posts: 19,996	Re: Bad Brake Booster? Usually a bad booster causes the brake pedal to be difficult to depress...not vice-versa. But if disconnecting the vacuum line solves it, then it must be the booster.

04-28-2008, 02:23 AM	#5
Sinister Between Trucks... Join Date: Mar 2002 Location: Los Angeles, CA. Posts: 3,830	Re: Bad Brake Booster? Could it possibly be the check valve? __________________ Beat it to fit, Paint it to match... Last edited by Sinister; 04-28-2008 at 02:23 AM.

04-28-2008, 02:27 AM	#6
EyeH8the24 Registered User Join Date: Dec 2004 Location: beulah,alabama Posts: 1,075	Re: Bad Brake Booster? is the check valve internal?

04-28-2008, 02:28 AM	#7
leddzepp Moderator Join Date: May 2007 Location: Southern Cal Posts: 19,996	Re: Bad Brake Booster? Hmmm...maybe the check valve is shot, and allowing TOO much vacuum to be pulled on the booster?? This sounds very reasonable to me, and a heck of a lot cheaper to fix!

04-28-2008, 02:31 AM	#8
dieselarmy13 Phone's ringin Dude. Join Date: Mar 2007 Location: Colorado Springs Posts: 1,426	Re: Bad Brake Booster? The ckeck valve is the plastic thingy that your vacuum line hooks onto on the booster. __________________ I pitty the fool with only two headlights!! 2003 SILVERADO SS--THE NEW GIRL 1972 GMC--THE OLD GIRL

04-28-2008, 02:32 AM	#9
leddzepp Moderator Join Date: May 2007 Location: Southern Cal Posts: 19,996	Re: Bad Brake Booster? The check valve is the plastic piece that the vacuum line connects to on the outside of the booster.

04-28-2008, 02:33 AM	#10
EyeH8the24 Registered User Join Date: Dec 2004 Location: beulah,alabama Posts: 1,075	Re: Bad Brake Booster? will try another check vale tomm then hope thats it ,it was working right one day ...get in it the next and was saying wth!

04-28-2008, 03:14 AM	#11
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,993	Re: Bad Brake Booster? ???? Did you just replace something.I ask because I am wondering if maybe the pedal is slightly depressed causing the booster/brakes to activate.The brake light switch or the rod out of adjustment? Just some other things to check. __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil"

04-28-2008, 04:51 AM	#12
EyeH8the24 Registered User Join Date: Dec 2004 Location: beulah,alabama Posts: 1,075	Re: Bad Brake Booster? i put the booster set up on a couple of months ago..and have driven the truck only around the shop as i was installing new engine and new 700r trans as well as swapping rearends..but it worked great till today.

04-28-2008, 05:27 AM	#13
67_C-30 I have a radical idea! Join Date: Jan 2005 Location: Sweet Home Alabama! Posts: 6,513	Re: Bad Brake Booster? Are you going to be at Mike's tomorrow? __________________ '67 C-30 Dually Pickup 6.2 Turbo Diesel, NP435 ‘72 C-10 SWB , 350 4bbl, TH350 '69 C-10 SWB , 250 L6, 3 OTT '69 GMC C3500, dump truck, 351 V6, NP435 '84 M1009 CUCV Military Blazer 67 C-30 Turbodiesel build thread http://67-72chevytrucks.com/vboard/s...d.php?t=254096 My trucks http://s226.photobucket.com/albums/d...ediafilter=all Member of the 1-Ton Club!

04-28-2008, 06:28 AM	#14
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: Bad Brake Booster? the check valve doesn't limit the vacume applied, it prevents the vacume from escaping. It's a new one by me... but it about has to be the booster.

04-28-2008, 09:21 AM	#15
leddzepp Moderator Join Date: May 2007 Location: Southern Cal Posts: 19,996	Re: Bad Brake Booster? yeah, i know it's purpose is to prevent it from escaping, but it's worth a shot as weird as this problem is!!



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04-28-2008, 11:27 AM	#16
bigblockorange Senior Member Join Date: Jan 2007 Location: central pa Posts: 428	Re: Bad Brake Booster? I had a similar problem with a pedal sticking I had to take apart my bracket and lever from behind my booster. I blasted all the parts painted them and never seized them. I then used seal grease and lubed the plunger shaft that is under the boot facing the firewall. This took care of my sticking problem. Good luck Attached Images __________________ I guess you could say I’m not really lazy I’m just real good at doing nothing!!!!

04-28-2008, 08:25 PM	#17
EyeH8the24 Registered User Join Date: Dec 2004 Location: beulah,alabama Posts: 1,075	Re: Bad Brake Booster? 67-c30...i was goin to mikes but my kids had different plans for me ..lol

04-29-2008, 01:26 AM	#19
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: Bad Brake Booster? bigblockorange, if you were to re-read the actual problem, you'll see that the pedal is not actually sticking, but getting sucked to the floor.

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