Excessive disc brake drag?
#1700054
11/17/14 03:41 PM
11/17/14 03:41 PM
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Joined: Oct 2003
Posts: 4,013 South Park, Pa.
68LAR
OP
master
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OP
master
Joined: Oct 2003
Posts: 4,013
South Park, Pa.
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I've asked this question before and never did get an acceptable answer. Stock drum rears Stock disc front end (A body spindles and calipers // B body rotors) Non power Stock master from '95 Dakota. (aluminum body, plastic reservoir) All pieces are in the stock location. Master is above the calipers and wheel cylinders. Problem is,.. It seem like there is excessive pad drag at the rotors. Any body have a solution for this problem??????? Thanks for any constructive input.
4 speed street legal. Best time 10.99 @ 124 mph on 93 octane pump gas @ 3926# total weight
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Re: Excessive disc brake drag?
[Re: 68LAR]
#1700055
11/17/14 03:45 PM
11/17/14 03:45 PM
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Joined: Jan 2003
Posts: 28,067 Irving, TX
feets
Senior Management
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Senior Management
Joined: Jan 2003
Posts: 28,067
Irving, TX
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The first question is how much drag do you get? There will be a bit of drag on them.
Do you have the springs installed over the pads? They help prevent unnecessary dragging.
In a properly designed brake system one inch of pedal movement only provides about .004" of pad movement. If the pads are too far away from the rotors you will end up with a soft or spongy pedal.
We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind. - Stu Harmon
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Re: Excessive disc brake drag?
[Re: feets]
#1700056
11/17/14 04:45 PM
11/17/14 04:45 PM
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Joined: Oct 2003
Posts: 4,013 South Park, Pa.
68LAR
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master
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OP
master
Joined: Oct 2003
Posts: 4,013
South Park, Pa.
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No springs on my calipers or pads. They are the slider type. Brake pedal moves about 1" max. Nice high hard pedal. I've had plenty of experiences with disc brake systems in my life time. My drag just seems to be a little more excessive than I've noticed on other cars. I realize that there will be a certain amount of drag with disc brake systems.
Since I'm working with a conversion brake system, is this inherent of going this route?
4 speed street legal. Best time 10.99 @ 124 mph on 93 octane pump gas @ 3926# total weight
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Re: Excessive disc brake drag?
[Re: 68LAR]
#1700057
11/17/14 04:52 PM
11/17/14 04:52 PM
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Joined: Jan 2003
Posts: 25,786 Rio Linda, CA
John_Kunkel
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 25,786
Rio Linda, CA
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Single-piston floating calipers depend on the distortion of the square-cut rubber ring to retract the piston ever so slightly, a small amount of disc runout helps...by nature they drag more than calipers with mechanical retractors.
If the rotors are really hot after a drive with minimum brake use there might be a problem.
The INTERNET, the MISinformation superhighway
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Re: Excessive disc brake drag?
[Re: John_Kunkel]
#1700058
11/17/14 05:20 PM
11/17/14 05:20 PM
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Joined: Aug 2005
Posts: 6,003 Salem
Grizzly
Moparts Proctologist
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Moparts Proctologist
Joined: Aug 2005
Posts: 6,003
Salem
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I pulled my hair out with the same issue as you, but all stock components. It STILL drags to much for my liking. Here is the thread, I start out just wanting to re-build a caliper, but if you read the whole thing it will at least give you an idea of what I tried. Help.
Mo' Farts
Moderated by "tbagger".
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Re: Excessive disc brake drag?
[Re: LAR_414]
#1700062
11/17/14 06:19 PM
11/17/14 06:19 PM
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Joined: Nov 2003
Posts: 36,040 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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I had 74 A sliders & one of em (LF) had what I thought was too much drag. I replaced it with a $15 rebuilt caliper & problem solved. It had significantly less drag than the one it replaced did
live every 24 hour block of time like it's your last day on earth
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Re: Excessive disc brake drag?
[Re: Paul_Fancsali]
#1700064
11/17/14 10:31 PM
11/17/14 10:31 PM
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Joined: Jan 2003
Posts: 15,355 Omaha Ne
TJP
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 15,355
Omaha Ne
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open a bleeder and see if it squirts fluid and then see if the drag is significantly reduced. If so now you have to establish why, 1. Internally collapsed hose 2. Wrong residual valve in the master 3. M/C pushrod too long.
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Re: Excessive disc brake drag?
[Re: Rick_Ehrenberg]
#1700066
11/18/14 01:53 AM
11/18/14 01:53 AM
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Joined: Nov 2003
Posts: 36,040 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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Rick is that correct or not correct that you want the one pad to have some side to side clearance (so it can float)? And the other pad you want to bend the end L tabs so you have to snap it into place on the caliper?
live every 24 hour block of time like it's your last day on earth
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Re: Excessive disc brake drag?
[Re: loaderpro]
#1700068
11/18/14 11:51 AM
11/18/14 11:51 AM
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Joined: Oct 2003
Posts: 4,013 South Park, Pa.
68LAR
OP
master
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OP
master
Joined: Oct 2003
Posts: 4,013
South Park, Pa.
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Let me take all the suggestions one by one. 1. Wheel bearings are adjusted properly. With no pads the rotors spin freely. 2. Brackets are brand new. Purchased from Dr Diff and installed last week. Had the same issue B4 that. 3. No residual valve that I'm aware of. Standard A Body to B body disc brake conversion. 4. Inside pad is floating on bracket. Outside pad snaps into caliper. 5. Everything you guys are suggesting is pointing to the calipers. I find that hard to believe, but facts is facts. Thanks for all the input.
4 speed street legal. Best time 10.99 @ 124 mph on 93 octane pump gas @ 3926# total weight
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Re: Excessive disc brake drag?
[Re: 68LAR]
#1700072
11/18/14 02:44 PM
11/18/14 02:44 PM
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Joined: Jan 2003
Posts: 28,067 Irving, TX
feets
Senior Management
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Senior Management
Joined: Jan 2003
Posts: 28,067
Irving, TX
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I'm still not sure what you call excessive drag.
Is there some way you can quantify the problem? Can you turn the wheel by hand? Can you spin the wheel without it stopping immediately upon release?
We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind. - Stu Harmon
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