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#1 |
Registered User
Join Date: Mar 2006
Location: San Ramon, California
Posts: 276
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Brake problems... Help please
I did the one ton brake conversion on my blazer. now that im driving it, the pedal goes almost all the way to the floor before it starts braking. but when it does start braking, the rears almost instantly lock up and it seems like the fronts do nothing. think this is a problem with the proportioning valve?
FYI the pedal is firm and does not go to the floor and stops the truck well when the vacuum boost line is taken off, so i know the m/c is good. Also, What are my options for proportioning valves?
__________________
My 1972 Blazer 5.3 E85/ NV4500 5spd 4x4 Work in Progress http://67-72chevytrucks.com/vboard/s...d.php?t=291482 ****SOLD!!!!!**** 1965 GMC 4X4 http://67-72chevytrucks.com/vboard/s...d.php?t=294727 |
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#2 |
Registered User
Join Date: Mar 2006
Location: San Ramon, California
Posts: 276
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Re: Brake problems... Help please
Could a mod move this into the p/u section so it might get more traffic?
__________________
My 1972 Blazer 5.3 E85/ NV4500 5spd 4x4 Work in Progress http://67-72chevytrucks.com/vboard/s...d.php?t=291482 ****SOLD!!!!!**** 1965 GMC 4X4 http://67-72chevytrucks.com/vboard/s...d.php?t=294727 |
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#3 |
Registered User
![]() Join Date: Nov 2007
Location: South Tx
Posts: 1,083
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Re: Brake problems... Help please
Sounds like there could be a couple of issues. You may not have gotten a good bleed on the front brakes..hence the pedal dropping to the floor. On top of that, you need to reduce the pressure in the line to your rear brakes....that's what's causing them to lock up too early. Depending on how original you want your engine compartment to be, an easy fix is one of these --> LINK.
It replaces your proportioning valve and lets you dial in the pressure to the rear brakes. You can also run your brake lights off the builtin pressure switch. I think CPP makes one too that you may even be able to pick up cheaper thru the forum vendor. Hope that helps. Last edited by AJs72K5; 03-01-2010 at 12:32 AM. |
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#4 |
Registered User
Join Date: Jan 2010
Location: houston, texas
Posts: 12
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Re: Brake problems... Help please
I have the same issue. i drove my Blazer the first time today and have the exact same issues. i am curious to the issue also. i changed over to the CPP brake booster with builtin propotioning valve. with no vacuum it is firm and stiff. when driving today it felt like the pedal also went all the way to the floor. bleed the entire system to make sure that the old fluid was gone. it was semi cloudy fluid and the new is perfectly clear. Hope some good ideas or advice happens here.
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#5 |
Registered User
Join Date: Feb 2003
Location: Santa Ana, CA
Posts: 2,191
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Re: Brake problems... Help please
Just thought I'd mention that the reservoirs are reversed on a 1 ton master cylinder. You need to replumb the master to prop valve lines so you are getting the right pressure and proportion to the front and rear cylinders. Otherwise, things will be jacked up. BTW, Inline Tube makes the prebent tube kit. I used them on my conversion and it worked perfectly.
Last edited by cleszkie; 03-01-2010 at 09:59 PM. |
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#6 | |
Registered User
Join Date: Mar 2006
Location: San Ramon, California
Posts: 276
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Re: Brake problems... Help please
Quote:
__________________
My 1972 Blazer 5.3 E85/ NV4500 5spd 4x4 Work in Progress http://67-72chevytrucks.com/vboard/s...d.php?t=291482 ****SOLD!!!!!**** 1965 GMC 4X4 http://67-72chevytrucks.com/vboard/s...d.php?t=294727 |
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