front brakes constantly sticking on 70 B body?
#619344
02/21/10 12:01 AM
02/21/10 12:01 AM
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Joined: Mar 2007
Posts: 254 Opelika, AL
JRs_Charger
OP
enthusiast
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OP
enthusiast
Joined: Mar 2007
Posts: 254
Opelika, AL
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Okay, the short version is, I have a 70 Charger with the original disc brakes up front.
The calipers are the original single piston style, and the rear brakes are the original drums. It was a factory power disc car, but someone has removed the brake booster and fitted a master cylinder from a 71-74 E body.
All the lines, calipers, and master cylinder all have less than a thousand miles on them. They are a few years old however, except for the master cylinder, it's new.
My problem is the front brakes drag constantly. Almost to the point where the left wheel cant be turned by hand once the car is jacked up. The right front isn't as noticeable, but it drags too.
Any ideas whats going on here? Aside from the deleted brake booster and the master cylinder from an E body, the rest of the brakes are as they were originally.
Any ideas where i should start looking?
I would appreciate any help, thanks!
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Re: front brakes constantly sticking on 70 B body?
[Re: JRs_Charger]
#619345
02/21/10 12:36 AM
02/21/10 12:36 AM
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Joined: Dec 2007
Posts: 18,157 Mass
DAYCLONA
I Live Here
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I Live Here
Joined: Dec 2007
Posts: 18,157
Mass
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As long as the master is a disk/drum unit it shouldn't matter in your application, unless your concern is originality,....seeing that your car was "converted" to manual disk, perhaps the swap isn't correct, linkage wise?,...sounds like residual pressure from the master is present,....are you able to pull the brake pedal up from it's current resting position?, if it's already against the frame stop, try disconnecting the pedal linkage, and jack the offending tire(s) off the ground and attempt turning,....BTW is the pedal push rod an adjustable threaded manual unit?
You got to do a little "diggin" and supply some more info
Mike
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Re: front brakes constantly sticking on 70 B body?
[Re: Hemiruss]
#619348
02/21/10 02:50 AM
02/21/10 02:50 AM
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Joined: Nov 2004
Posts: 9,312 SoCal
68HemiB
master
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master
Joined: Nov 2004
Posts: 9,312
SoCal
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I second the recommendation to crack the bleeder on the offending wheel when you find it dragging.
That will at least isolate it between something that is holding pressure in the system [if cracking the bleeder releases the brakes] versus a mechanical hangup of the piston, sliders, etc [if cracking the bleeder has no effect].
Down to just a blue car now.
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Re: front brakes constantly sticking on 70 B body?
[Re: 68HemiB]
#619349
02/21/10 09:53 AM
02/21/10 09:53 AM
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Joined: Nov 2005
Posts: 836 lancaster, new york
macmic87
super stock
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super stock
Joined: Nov 2005
Posts: 836
lancaster, new york
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my friends went through this situation last summer. it ended up being the proportion valve. now you say it is original and theirs was not, but there was a problem internally with a washer that was not of the right shape that let it act as a check valve and would hold the brakes (this problem was addmitteed to by the vendors at carlisle last summer). also here is a thread that may help to diagnose. https://board.moparts.org/ubbthreads/show...;gonew=1#UNREAD
Last edited by macmic87; 02/21/10 10:00 AM.
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Re: front brakes constantly sticking on 70 B body?
[Re: JRs_Charger]
#619353
02/21/10 05:21 PM
02/21/10 05:21 PM
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Joined: Sep 2005
Posts: 6,516 Santa Cruz, California
Lefty
master
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master
Joined: Sep 2005
Posts: 6,516
Santa Cruz, California
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Quote:
My problem is the front brakes drag constantly
In my experience that's usually caused by there not being a gap between the brake pedal rod and piston in the MC or booster to MC interface.
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Re: front brakes constantly sticking on 70 B body?
[Re: Lefty]
#619354
02/23/10 12:43 AM
02/23/10 12:43 AM
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Joined: Mar 2007
Posts: 254 Opelika, AL
JRs_Charger
OP
enthusiast
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OP
enthusiast
Joined: Mar 2007
Posts: 254
Opelika, AL
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Well, I finally had a few minutes to spend on it. I didn't get to check the proportioning valve, or the master cylinder, however I did notice a couple of things.
First off, cracking the brake bleeder showed that there was no line pressure on it. So I assume that the master cyl isn't sticking open now?
When I put a c clamp on the caliper piston to compress it, there was alot of resistance. It was a major pain to get the piston to go back in the bore. This was more prevalent in the left caliper than the right.
I bought the calipers as remans in 04, and the car has sat alot since. So Is it possible that these things are corroded on the inside maybe? Or something else I'm missing? The brake lines have less than 5000 miles on them, as does the 1 year old master cylinder. The proporting valve is the original and who knows what's going on inside it, i havent pulled it yet.
Thanks again for the help guys, I appreciate it!
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