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

macblazer · 10-04-2008, 11:14 PM

ok...I've been banging this one around for a bit and I'm not sure what the deal is.

A little back ground.

1972 Chevy C-10 Cheyenne long bed
The entire brake system was replaced with new parts not long after I bought it. (new brake booster, new master cylinder, new front rotors, new front calipers, new rear drums, new rear pads and shoes. Basically everything except the lines from the front to the back)

About 4 months ago we pulled the old 350 out and tore it down.

The motor now has a 410 horsepower Edlebrock top end kit.
new heads, new intake, new sealed power high compression pistons, new camshaft, new rockers, etc etc. The only thing we kept was the block, the crank and the rods. The entire motor other than those is brand new.

Now to the issue.

The truck just doesn't seem to have the brake power that it should. I've heard people say that when you do a large amount of performance upgrades that sometimes you can run into issues the vacuum not being high enough for the vacuum brake booster.

the truck won't lock up the brakes anymore. I mean I can slam them to the floor and it will slow down and eventually stop, but it doesn't have the stopping power I would expect. It's almost like I'm just not getting the amount of pressure I would expect.

Any ideas of things I can check?

Heavy Evy · 10-04-2008, 11:39 PM

Somtimes bigger cams don't make enough vacum for the brake booster and alot of people run vacum canisters to compensate for the lost vacum, also there maybe air in the system you should try bleeding the brakes and the master cyl.

macblazer · 10-04-2008, 11:43 PM

Quote:

Originally Posted by Heavy Evy

Somtimes bigger cams don't make enough vacum for the brake booster and alot of people run vacum canisters to compensate for the lost vacum, also there maybe air in the system you should try bleeding the brakes and the master cyl.

Yeah I think I might take it back to my guys that I had do the brake system and have the bleed out the entire system.

It sat outside for about 4-5 months with the hood off and the engine out of it while we were rebuilding the motor so I wouldn't surprise me if some moisture got into the vacume booster.

Does any one have some suggestions on what kind of vacuum canister I should get for this truck if I wanted to try that?

**VetteVet** · 10-05-2008, 12:06 AM

See if this helps.
http://www.classicperform.com/TechBo...oubleshoot.htm

macblazer · 10-05-2008, 12:07 AM

Quote:

Originally Posted by VetteVet

See if this helps.
http://www.classicperform.com/TechBo...oubleshoot.htm

I'll check it out. Thanks!

PanelDeland · 10-05-2008, 06:07 AM

First thing I would do is check vacuum.If it's low then you may need a canister.If not you may just need to rebleed(shouldn't but....)You could also have a cracked or loose hose.I would check thosse before i threw $$$ at it.

Cyclone44 · 10-05-2008, 07:05 AM

Quote:

Originally Posted by PanelDeland

First thing I would do is check vacuum.If it's low then you may need a canister.If not you may just need to rebleed(shouldn't but....)You could also have a cracked or loose hose.I would check thosse before i threw $$$ at it.

10-04-2008, 11:14 PM	#1
macblazer Registered User Join Date: Jul 2008 Location: Austin, Tx Posts: 23	Brake Issue ok...I've been banging this one around for a bit and I'm not sure what the deal is. A little back ground. 1972 Chevy C-10 Cheyenne long bed The entire brake system was replaced with new parts not long after I bought it. (new brake booster, new master cylinder, new front rotors, new front calipers, new rear drums, new rear pads and shoes. Basically everything except the lines from the front to the back) About 4 months ago we pulled the old 350 out and tore it down. The motor now has a 410 horsepower Edlebrock top end kit. new heads, new intake, new sealed power high compression pistons, new camshaft, new rockers, etc etc. The only thing we kept was the block, the crank and the rods. The entire motor other than those is brand new. Now to the issue. The truck just doesn't seem to have the brake power that it should. I've heard people say that when you do a large amount of performance upgrades that sometimes you can run into issues the vacuum not being high enough for the vacuum brake booster. the truck won't lock up the brakes anymore. I mean I can slam them to the floor and it will slow down and eventually stop, but it doesn't have the stopping power I would expect. It's almost like I'm just not getting the amount of pressure I would expect. Any ideas of things I can check?

10-04-2008, 11:39 PM	#2
Heavy Evy born to lose Join Date: Sep 2008 Location: Salt Lake City, Utah Posts: 842	Re: Brake Issue Somtimes bigger cams don't make enough vacum for the brake booster and alot of people run vacum canisters to compensate for the lost vacum, also there maybe air in the system you should try bleeding the brakes and the master cyl. __________________ _____________________ '67 Chevy Belair Wagon 283 Powerglide '68 Chevy II Nova 2 door 350 TH400 Sold!! '71 Chevy C20 350 TH350 '71 Chevy C10 Burb 350 TH350 stolen totalled gone.... Burb Build http://67-72chevytrucks.com/vboard/s...d.php?t=475155 Nova Build http://67-72chevytrucks.com/vboard/s...d.php?t=498979 Wagon Build http://67-72chevytrucks.com/vboard/s...d.php?t=543052 Not giving a truck.

10-05-2008, 12:06 AM	#4
VetteVet Msgt USAF Ret Join Date: Jan 2005 Location: Kalamazoo, Michigan Posts: 8,718	Re: Brake Issue See if this helps. http://www.classicperform.com/TechBo...oubleshoot.htm __________________ VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative.

10-05-2008, 06:07 AM	#6
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,992	Re: Brake Issue First thing I would do is check vacuum.If it's low then you may need a canister.If not you may just need to rebleed(shouldn't but....)You could also have a cracked or loose hose.I would check thosse before i threw $$$ at it. __________________ 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" Last edited by PanelDeland; 10-05-2008 at 06:08 AM.



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