71 power brake vacuum booster problems - The 1947 - Present Chevrolet & GMC Truck Message Board Network

farmsweet · 12-19-2012, 08:42 PM

Okay I just finished installing my engine and was wondering if anyone out there had an idea on how to get more vacuum for my power brake booster. I already installed the summit vacuum canister but it ant helping much. any ideas would be much appreciated.......thanks
71 c10 bbc 468 cu with a mother thumpr cam

Lee H · 12-19-2012, 09:03 PM

Electric vacuum pump. Summit has these also.
Posted via Mobile Device

GASoline71 · 12-20-2012, 12:13 AM

Only way you'll get more vacuum out of that engine is to run a different cam.

Or by chance, you need a dedicated vacuum line to the booster (or canister in your case) If you "T" the vacuum line and use it for another accessory (like the tranny modulator) you'll get even weaker vacuum to the booster.

Gary

farmsweet · 12-20-2012, 05:47 PM

thanks guys ....I will check out the electric pumps at summit or maybe take the booster off and get a master cylinder off a bb corvette.

PanelDeland · 12-20-2012, 07:53 PM

You could also check out the Hydro-boost set up.It will use pressure from the PS pump and not require any vacuum.There is a thread on it if yo're interested.

68gmsee · 12-20-2012, 09:08 PM

Quote:

Originally Posted by farmsweet

thanks guys ....I will check out the electric pumps at summit or maybe take the booster off and get a master cylinder off a bb corvette.

If you drive it around a lot -especially around town -you won't like it without power brakes. Been there. Go with electric or hydro boost (if you have power steering) as mentioned above if you have to.

hugger6933 · 12-20-2012, 09:21 PM

Your best option is the hydro boost one.

hugger6933 · 12-20-2012, 09:32 PM

Also, before you blame the cam size I know the mutha thumpas are pretty big, just check with some carb cleaner and make sure you don't have a vaccum leak. Almost every comp cam I ever ran made fairly decent vaccum and that one is designed to sound bad more than be bad [from what I gather from the advertising]. Another point to be made IF the cam is indeed large enough that it is killing the vaccum, it is also gona be bleeding off a lot of needed compression in the big block, but I'm sure you thought all of that out when planning the build. If I have stepped on toes or told you a bunch of stuff you already know I am sorry. Some people go to the cam page and are bottom pagers, meaning they go to the bottom of the page and order the biggest cam no matter what their set up is. They may get some thing large and huge when all they needed was a little more lift. That is the biggset mistake a lot of first timers in the hot rodding truck building hobby make. Getting WAY too much cam for a near stock setup. Rant off and like I said check for leaks if you havnt thought of it and look int ooa hydro boost if all is well. Jim

nra4life · 12-21-2012, 03:22 AM

I agree with hugger. If the cam is too mild, the engine won't quite live up to its full potential. If the cam is too hot, the engine won't do anything well. To err mild is far better than to err wild.

*bk2life* · 12-21-2012, 04:14 AM

mutha thumpr has big over lap/exhasut dur, your guna have low vacuum. you cna use a vacuum pump, but if have the oppertunity hydro boost will never let you down, and has amazing brake pressures, and gives you alot of room for header install

12-19-2012, 08:42 PM	#1
farmsweet Registered User Join Date: Oct 2012 Location: Madison Posts: 9	71 power brake vacuum booster problems Okay I just finished installing my engine and was wondering if anyone out there had an idea on how to get more vacuum for my power brake booster. I already installed the summit vacuum canister but it ant helping much. any ideas would be much appreciated.......thanks 71 c10 bbc 468 cu with a mother thumpr cam

12-19-2012, 09:03 PM	#2
Lee H Registered User Join Date: Jun 2010 Location: Upland Ca Posts: 4,150	Re: 71 power brake vacuum booster problems Electric vacuum pump. Summit has these also. Posted via Mobile Device __________________ 1972 C10 SWB, Air, PS, PB, 350/350THM. Second owner. 1965 Corvette roadster, 44K miles, 327/365 SHP, 4 speed, side exhaust, knockoffs, teak, second owner (bought in 1970), Have ALL numbers matching components. My frame off restoration thread: http://67-72chevytrucks.com/vboard/s...d.php?t=556703

12-20-2012, 05:47 PM	#4
farmsweet Registered User Join Date: Oct 2012 Location: Madison Posts: 9	Re: 71 power brake vacuum booster problems thanks guys ....I will check out the electric pumps at summit or maybe take the booster off and get a master cylinder off a bb corvette.

12-20-2012, 07:53 PM	#5
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,992	Re: 71 power brake vacuum booster problems You could also check out the Hydro-boost set up.It will use pressure from the PS pump and not require any vacuum.There is a thread on it if yo're interested. __________________ 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"

12-20-2012, 09:21 PM	#7
hugger6933 Registered User Join Date: Oct 2008 Location: Marianna Arkansas Posts: 7,280	Re: 71 power brake vacuum booster problems Your best option is the hydro boost one.

12-20-2012, 09:32 PM	#8
hugger6933 Registered User Join Date: Oct 2008 Location: Marianna Arkansas Posts: 7,280	Re: 71 power brake vacuum booster problems Also, before you blame the cam size I know the mutha thumpas are pretty big, just check with some carb cleaner and make sure you don't have a vaccum leak. Almost every comp cam I ever ran made fairly decent vaccum and that one is designed to sound bad more than be bad [from what I gather from the advertising]. Another point to be made IF the cam is indeed large enough that it is killing the vaccum, it is also gona be bleeding off a lot of needed compression in the big block, but I'm sure you thought all of that out when planning the build. If I have stepped on toes or told you a bunch of stuff you already know I am sorry. Some people go to the cam page and are bottom pagers, meaning they go to the bottom of the page and order the biggest cam no matter what their set up is. They may get some thing large and huge when all they needed was a little more lift. That is the biggset mistake a lot of first timers in the hot rodding truck building hobby make. Getting WAY too much cam for a near stock setup. Rant off and like I said check for leaks if you havnt thought of it and look int ooa hydro boost if all is well. Jim

12-21-2012, 03:22 AM	#9
nra4life Registered User Join Date: Sep 2009 Location: Lee's Summit, Missouri Posts: 24	Re: 71 power brake vacuum booster problems I agree with hugger. If the cam is too mild, the engine won't quite live up to its full potential. If the cam is too hot, the engine won't do anything well. To err mild is far better than to err wild.

12-21-2012, 04:14 AM	#10
bk2life Account Suspended Join Date: Oct 2012 Location: phx, az Posts: 868	Re: 71 power brake vacuum booster problems mutha thumpr has big over lap/exhasut dur, your guna have low vacuum. you cna use a vacuum pump, but if have the oppertunity hydro boost will never let you down, and has amazing brake pressures, and gives you alot of room for header install



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