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Discussion Starter #1
I have a 69 FB that I noticed before I put her away for winter storage that the rear Pass. brake drum was locking up. I did not really get into finding out why.. I did adjust them a few times and it did not seem to help. I noticed the paint on the drum was burning off and one of the shoes was cracked. I did not feel like working on it in the freezing cold weather. Now that it is time to enjoy the mustang again I need to figure out what is going on. All the shoes and hardware including the wheel cylinders were replaced about 7 years ago. Seems like a long time, but considering the car is not a daily driver and is stored in the winter everything appears to be in good shape. The drums are old and could stand to be replaced. I am thinking it might be a bad wheel cylinder. What do you guys think? Is there a good way to test this? Any suggestions on how to track down the problem. I don't want to just throw a bunch of money at replacing parts that don't need replaced. I don't think it is the porp. valve as my brake warning light is not on. Like it had been in the past before I replaced the valve.. Thanks for any hints on what to look at!
 

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If they are not adjusted too tight causing a drag on the drum which is heating the drum and shoe to crack.
Then I would look into the possiablity of a partually plugged brake line or wheel cyl is in need of cleaning/rebuild.
Your discription of the oneside locking leads me to think the shoes are not retracting fully after being applied.
Is the shoes cracking on the tops? Yes... then look into the weak springs/sticking wheel cyl.
 

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Is this a front disc brake car? I ran into issues when I got my '68 going that ended up being a proportioning valve that needed rebuilt. It would pass pressure to the rear but not allow the pressure to bleed back correctly. I would agree a pinched or plugged brake line could do the same thing.

With my car, the rear driver side was what dragged.

Just another idea.
 

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Discussion Starter #5
Well from the factory it was not a front disc car. I have added Granada discs up front. And at that time I rebuilt the Granada Prop. valve. I guess I can bleed the brakes and see how much fluid i am getting when pumping on the problem wheel cylinder. I'd think it it was a plugged line the amount of fluid would be less?
 

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Discussion Starter #6
Is this a front disc brake car? I ran into issues when I got my '68 going that ended up being a proportioning valve that needed rebuilt. It would pass pressure to the rear but not allow the pressure to bleed back correctly. I would agree a pinched or plugged brake line could do the same thing.

With my car, the rear driver side was what dragged.

Just another idea.
Did this allow your brake warning light come on? That's what happened to mine before I rebuilt it..
 

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Plugged line yes, but if the line is staying pressurized no. Also if it were plugged would it be braking at all? Meaning it wouldn't push the shoe at all.. let alone staying locked up.
 

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Did this allow your brake warning light come on? That's what happened to mine before I rebuilt it..
My memory was I did not have any light come on. I had replaced literally everything else in my car, and the funny thing was at first when I started driving it, it was just fine. Then after a few weeks it started dragging.

The proportioning valve was the only part of the braking system that hadn't been replaced so I decided to take it apart and rebuild it. I think sitting 20 years in a barn, it had crud and after brake fluid going through it it loosened the rust up in there??

It has been fine since.

Good luck with your issue. I messed up a brand new pair of shoes having that wheel drag all the time.
 

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I have a 69 FB that I noticed before I put her away for winter storage that the rear Pass. brake drum was locking up. I did not really get into finding out why.. I did adjust them a few times and it did not seem to help. I noticed the paint on the drum was burning off and one of the shoes was cracked. I did not feel like working on it in the freezing cold weather. Now that it is time to enjoy the mustang again I need to figure out what is going on. All the shoes and hardware including the wheel cylinders were replaced about 7 years ago. Seems like a long time, but considering the car is not a daily driver and is stored in the winter everything appears to be in good shape. The drums are old and could stand to be replaced. I am thinking it might be a bad wheel cylinder. What do you guys think? Is there a good way to test this? Any suggestions on how to track down the problem. I don't want to just throw a bunch of money at replacing parts that don't need replaced. I don't think it is the porp. valve as my brake warning light is not on. Like it had been in the past before I replaced the valve.. Thanks for any hints on what to look at!
Many of the brake springs are made in China, Mexicao etc regardless of the label....5-7 years is about max on them.
 

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If you've checked and/or replaced all the basic, brake shoes reasonably adjusted, ebrake maybe not even connected to help troubleshoot and you're still smokin shoes then your problem is a collapsed rubber brake hose on your rear axle. This happens way more than folks know. Rubber hoses collapse from the inside and you NEVER see it. This has happen to me on 3 cars. One was a caliper sticking but nothing wrong with it. Another way is you try to bleed a line and not much comes out. I had a SHO that both rear rubber lines collapsed at same time. Couldn't bleed either side. Easy enought o prove out.
 

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Wow, I'm feeling old here.

Drum brakes lock up when there is a brake fluid leak from the wheel cylinder. It doesn't take much at all. The pads soak up the fluid and skreetch... Normally, you really can't get the fluid out of the linings, unless you bake them very hot or torch them but nowadaze, they are so cheap just replace them after you fix the wheel cylinder.

Btw 7 years is a long time if you don't replace the brake fluid or drive the car a lot. I try and do mine every other year or so. Brake fluid absorbs water and I bet you will find tiny pits in the wheel cylinder.

M
 

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Discussion Starter #13
Cool lots of good suggestions here for me to check out.. Thanks guys. I'll plan on flushing the fluid as well. More to come when I get a chance to dig into them..
 

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Discussion Starter #15
Yeah will do.. I am thinking I might rebuild both rear brakes right now. I am heading down to Lake of the Ozarks this weekend. They have a Mustang salvage yard down there. I am thinking I can find a decent set of drums there. Pick them up have them turned and clean them up. New springs\hardware and shoes hopefully I'll be good to go. Of coruse before I drop all that money I plan on checking what kind of fluid I get from bleeding the rear brakes. I'll post back..
 

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Sorry for reviving a dead thread but I've got a 65 coupe with front disk and rear drum and the right rear brake is EXTREMELY touchy (like you barely press the brake pedal and that wheel locks up) when its cold. After making 3-4 gentle stops the right rear brake stops being touchy and functions correctly. Any ideas on what this could be?
 

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Could be a leaky axle seal contaminating the brake lining. Brake gets hot and burns up the fluid and it stops until it gets wet again.. spray brake cleaner on shoe lining and backing plate then drive, if it goes away for a while then fix seal and buy new shoes
 

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Correct me if I'm wrong, here. I may have missed it on the other posts on this thread. First thing you check for a problem like this is; have you positioned the primary, ie short shoe, to the front. Having the secondary, ie long shoe, at the front will cause this problem. Also, be sure to size the new shoes to the drum.
 
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