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Discussion Topic:
dragging brakes
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Dustbowl |
02-12-2011 @ 6:08 PM
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Member
Posts: 74
Joined: Feb 2011
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I have 39 (i think) Ford juice brakes in my 36 Ford. For some reason I don't understand, the front brakes start dragging when I am driving. The problem is intermittent; it comes and goes. It must be happening to both front wheels as I don't find the car pulling on way or another. The brake shoes are fairly new, the hydraulic system seems in good condition. Brake adjuster is fully retracted on both wheel. Inspecting with wheel off does not show anything amiss, that I can see. Back wheels turn easily so I guess there is no abnormal hydraulic pressure. Has anyone else experienced this problem? Suggestions?thanks
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alanwoodieman |
02-12-2011 @ 8:32 PM
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Senior
Posts: 868
Joined: Oct 2009
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what process did you use to adjust them?, 39 to 41 or 42 had several adjustments for each shoe, also is the large shoe on the front or rear of backing plate in the rolling direction, also check to make sure the master cylinder is retracting fully, if not it will cause the brakes to drag. Adjust the brakes in a warm condition, I know it seems nuts but brake drums/brake shoes expand when they get hot. Just some things to check
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TomO |
02-13-2011 @ 9:03 AM
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Senior
Posts: 7256
Joined: Oct 2009
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You might not have enough free play in the brake pedal. It should be between 1/4" and 1/2" and measured with the floorboards and mat in place. Your anchor bolts could also be out of adjustment, causing the bottom of the shoes to drag.
Tom
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Texas40 |
02-13-2011 @ 9:29 AM
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Member
Posts: 66
Joined: Oct 2009
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How old are your front flex hoses from the junction block to the wheel cylinders. I have seen old ones that accept the hydraulic pressure from the master cylinder going into the wheel cylinders but restrict the pressure release from the return springs once the master cylinder is relaxed. Everything seems normal except pressure is still exerted inside the wheel cylinder to the shoes.
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supereal |
02-13-2011 @ 10:37 AM
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Senior
Posts: 6819
Joined: Oct 2009
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If the problem arises after driving for a while, it is almost always due to the master cylinder. As said above, it is necessary to have some pedal "free play" to allow the piston to retract far enough to allow the ports between the cylinder and the reservoir to be opened. Also, master cylinders have a valve built into them to maintain some residual pressure so you don't have to pump the pedal each time you apply the brakes. If time and/or contaminated fluid has caused this valve to stick, or otherwise fail, pressure will be built up, first in the front brakes, which are closest to the master cylinder. I've seen this build up grow until a vehicle can't be moved. The cure is a replacement of the master cylinder. Carry a wrench with you, and if the brakes begin to grab, open one of the bleeder screws just a bit to allow some fluid to come out, then retighten. If the brakes release, you have confirmed the cause laid out above.
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