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#1 |
Registered User
![]() Join Date: Sep 2010
Location: Northport, Alabama
Posts: 1,353
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New Power Brake Booster - NOT BOOSTING !!!
. . . .
During my 1970 350's restoration, a new booster / master cylinder was installed and front disc's were added. I can hear the rush of air when the vacuum line is pulled off and the hose is connected to a good source. The pedal doesn't feel like "power brakes" - the truck stops a little better now, but that's probably because of the added front disc's. It just doesn't feel like what I remember power brakes in the 70's were like. Does anyone have anymore ideas of what to check ? . . . .
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. . . . Life is short . . . we only have, right now. . . . . My 70 C-10's BUILD THREAD: http://67-72chevytrucks.com/vboard/s...d.php?t=475526 Last edited by Steve Hafner; 12-04-2011 at 12:33 PM. |
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#2 |
Old Skool Club
![]() Join Date: Jun 2001
Location: Benton, AR "The Heart of Arkansas"
Posts: 10,880
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Re: New Power Brake Booster - NOT BOOSTING !!!
What about the push rod from the pedal to the master cylinder? Is there a difference between PB and non-PB rod? It seems I recall in some apps, that there is a difference. It may not be so, but it's just a question.
My truck had power brakes before the conversion, so I can't answer my own question. Who was your supplier? If it is ECE, give 'em a call. They were good to answer issues for me.
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Member Nr. 2770 '96 GMC Sportside; 4.3/SLT - Daily driven....constantly needs washed. '69 C-10 SWB; 350/TH400 - in limbo The older I get, the better I was. |
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#3 | |
Registered User
![]() Join Date: Sep 2010
Location: Northport, Alabama
Posts: 1,353
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Re: New Power Brake Booster - NOT BOOSTING !!!
Quote:
It was purchased at CPP ( Classic Performance Parts ) If know body else on here has any ideas, I guess I'll have to call them and see what they say. |
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#4 |
Registered User
Join Date: Oct 2005
Location: Overland Park, Ks.
Posts: 5,216
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Re: New Power Brake Booster - NOT BOOSTING !!!
I have the same thing. I bought mine from CPP also. It is a Delco Moraine new unit. I just have been liveing with it for 2-3 years now. It stops OK & has a good pedal but like you say it just doesn't feel like power brakes. Let us know what happens. They have a lifetime warranty.
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#5 |
Registered User
Join Date: Dec 2007
Location: Southington CT
Posts: 548
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Re: New Power Brake Booster - NOT BOOSTING !!!
got any pictures of your boosters? Is it a single or duel diaphragm?
Also might want to check the amount of VAC you have at the booster, might be building some pressure, but maybe not enough to take full advantage of the boosters ability. |
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#6 | |
Registered User
![]() Join Date: Sep 2010
Location: Northport, Alabama
Posts: 1,353
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Re: New Power Brake Booster - NOT BOOSTING !!!
Quote:
Thanks !!! I'll have to have someone check the vacuum for me. Here's a picture from CPP, where I bought it. Mine looks just like this and is for a disc - drum setup. That rod on the far right was adjusted to have a fairly low pedal. I'll attach a picture of the interior to show the pedals height too, it's not REAL low - just lower then it was with manual brakes. . . . . |
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#7 |
Registered User
Join Date: Aug 2009
Location: Alden NY
Posts: 2,705
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Re: New Power Brake Booster - NOT BOOSTING !!!
There is a small rod that goes from the booster to the back of the MC. It is adjustable. You must unbolt the MC (you should be able to leave your lines hooked to it) and move it forward enough to see the rod. The end of the rod can be adjusted out (5/16" wrench if I remember correctly) to increase the role of the booster. Too much out will have your brakes dragging. You have to adjust some, try it out, and maybe readjust. The inside pedal rod does nothing to adjust the booster.
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1961 C1 Corvette 1959 El Camino 350 TPI, 9" 4 w disc 69 Blazer K5 - sold July '20 2021 Durango RT 5.7 |
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#8 | |
Registered User
![]() Join Date: Sep 2010
Location: Northport, Alabama
Posts: 1,353
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Re: New Power Brake Booster - NOT BOOSTING !!!
Quote:
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#9 |
Registered User
Join Date: Jun 2011
Location: Green Cove Springs FL
Posts: 194
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Re: New Power Brake Booster - NOT BOOSTING !!!
Also, is your motor stock? A larger then stock cam will create less vacuum, and sometimes not enough to run power brakes
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68 SWB Fleet 383 |
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#10 |
Registered User
![]() Join Date: Sep 2010
Location: Northport, Alabama
Posts: 1,353
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Re: New Power Brake Booster - NOT BOOSTING !!!
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#11 |
Registered User
Join Date: Aug 2010
Location: Hoofddorp, the Netherlands
Posts: 582
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Re: New Power Brake Booster - NOT BOOSTING !!!
what brand brake disks and pads are you using? wrong pads will definitly give you that feel, like they're just not digging in or like you've burned you're pads.
the brake paddle will still feel rock hard, but there's just no responds.
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Feedback is always welcome! projects: 1969 Chevy C10 1950 GMC 100 1958 Chevy C60 Viking ratrod |
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#12 |
Registered User
Join Date: Feb 2003
Location: Santa Ana, CA
Posts: 2,191
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Re: New Power Brake Booster - NOT BOOSTING !!!
Did you upgrade your proportioning valve for disc brakes up front? If not, you need to do this to get the proper fluid flow to the front calipers.
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#13 |
Registered User
![]() Join Date: Sep 2010
Location: Northport, Alabama
Posts: 1,353
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Re: New Power Brake Booster - NOT BOOSTING !!!
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