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04-27-2007, 09:29 PM
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#1 |
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Registered User
Join Date: Apr 2007
Location: Ontario
Posts: 3
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Weird brake problem
This is my first post on your site, nice site too I might add. Has alot of great info.
I have a 69 930 (1 ton) that is suffering from a weird brake problem and am unable to nail it down. The problem is the rear brakes provide almost all of the braking and when its wet out the thing is just a nightmare to drive. The master cylinder has been changed and all the lines bled many times so air is not the problem. It will also brake straight so a bad flex line is not really an option as well. I took a picture of the booster master cylinder set up just in case what is on there is not what it should be. Thanks a bunch Jason |
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04-27-2007, 09:36 PM
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#2 |
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Registered User
Join Date: Mar 2005
Location: San Bernardino, CA
Posts: 57
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Re: Weird brake problem
Does the booster have a leak? If it did your idle would fluctuate when you pressed on the brakes. Also what about the slave cylinders on the drums.
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04-27-2007, 09:51 PM
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#3 |
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Designated A-hole!
Join Date: Mar 2003
Location: South Mississippi
Posts: 36,450
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Re: Weird brake problem
Did you do anything with the shoes on the front brakes? Are they adjusted correctly, are the adjusters installed correctly? How do the wheel cylinders look?
BTW Welcome to the board from South Mississippi! 
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"If it ain't broke, fix it 'til it is!" Being stupid ain't illegal.  We're Still Debt Free Except for the House!!! www.daveramsey.com 70 GMC SWB Stepside project "Green Booger" soon to be 6.0l/4l80e 93 S-10 "Poppaw's Truck" |
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04-27-2007, 09:55 PM
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#4 |
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its all about the +6 inches
Join Date: Jan 2001
Location: Hilliard Ohio
Posts: 2,693
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Re: Weird brake problem
Sounds like the front shoes need adjusted.
A bad booster is out of the question, and on the daul diaphram booster, you'd more likely idle funny, but still have power assist... I lost an engine to a bad booster on my one ton due to that. |
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04-28-2007, 09:02 AM
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#5 |
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Hellasick
 
Join Date: Jul 2006
Location: Death Moans, IA
Posts: 876
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Re: Weird brake problem
How old are the front brake hoses? They could be swollen almost shut. Even though they bleed, just not enough volume getting through.
__________________
I keep two MAGNUMS in my desk. One's a gun, and I keep it loaded. The other's a bottle and it keeps ME loaded. I'm Tracer Bullet. (Calvin and Hobbes) This life was a test. It was only a test. If this had been an actual life, you would have received instructions on where to go and what to do. RED meat is not bad for you...FUZZY BLUE/GREEN MEAT is bad for you!!!!!!!!!!!!! BUILT FORD TOUGH WITH CHEVY STUFF--sticker at Goodguys |
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04-28-2007, 09:20 AM
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#6 |
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Registered User
Join Date: Jun 2006
Location: Raleigh, NC
Posts: 7
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Re: Weird brake problem
incorrect proportioning valve?
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04-30-2007, 09:52 PM
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#7 |
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Registered User
Join Date: Apr 2007
Location: Ontario
Posts: 3
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Re: Weird brake problem
All the front brakes are new and have been adjusted,checked and checked again.
Idle is good and like was mentioned the booster itself should not cause troubles with the front but not the rear. The flex lines are one possibility but the only thing is both front wheels provide the same braking force. (will check to see if there weather checked and may just replace them to rule them out). The proportioning valve is the thing i keep looking at. Can anyone tell me if that valve in the picture I provided is what should be used on this vehicle or has someone installed the wrong unit? Thanks for the replys Jason |
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04-30-2007, 09:57 PM
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#8 |
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Post Whore
Join Date: Aug 2005
Location: Owensboro KY
Posts: 11,905
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Re: Weird brake problem
That prop valve looks nothing like the one on my truck but since my truck has discs up front that probably doesn't help you.
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Drew '71 Chevy 350/TH350 Hugger Orange Currently just a rolling frame, body work soon to follow!!! Check out my Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=212927 Daily Driver: 1997 Chevrolet S-10 with more gears than pistons 
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05-01-2007, 07:38 PM
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#9 |
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Registered User
Join Date: Apr 2007
Location: Ontario
Posts: 3
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Re: Weird brake problem
I am 99% sure that the set up for disc/drum is different for drum/drum.
Jason |
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05-01-2007, 07:48 PM
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#10 |
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member #16
 
Join Date: Dec 1999
Location: Yuba City Ca.
Posts: 3,618
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Re: Weird brake problem
That is a distribution valve on your truck, and is the right one for your truck if you have drums all around. . It separates your front and rear systems and houses the warning light. Disc brake systems use a prop valve to proportion front to rear balance.
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john http://67-72chevytrucks.com/vboard/showgroups.php board vendors  http://www.flickr.com/photos/1745471...7602865984234/ Last edited by john; 05-01-2007 at 07:50 PM. |
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05-01-2007, 08:51 PM
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#11 |
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Registered User
Join Date: Mar 2007
Location: Ben Wheeler,Texas
Posts: 992
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Re: Weird brake problem
maybe stupid....what about the valve on the side of the booster?Also, can the distribution valve be bad?? My '69, before I replaced the rear drums pulled hard to the right, found the right front wheel cyl. was leaking. FIXED right?? Nope! Not until last week when I swapped my rear axles to five lug and put NEW drums on. My rear brakes would also lock up on me if I had to make a hard stop,before I replaced the rear parts I mentioned. I would check your adjusters on the rear,mine were nearly all the way out,even with new shoes the PO had put on. Some machine shops will turn them even if they are past the safe zone...
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05 2500HD 6.0 excab 69 LWB-Gone but not forgotten! 68 Dodge Charger 383/727 69 Dodge Charger-440/4spd |
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