Rear drums on '74 Dart Sport. What would cause one of them to ocassionally lock up and slide? Also sometimes has a severe shudder on braking.

Jerry

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There's a difference between ignorance and stupidity.
Ignorance is not knowing any better.
Stupidity is knowing, yet doing it anyway.

Shudder is usually warped rotors. Premature rear lockup is a brake bias problem if there are no other mechanical faults like out of round drums, leaking seals, etc.

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Joshua

You can also get a lockup problem if the shoes are out of adjustment.

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

What is this?

_________________
There's a difference between ignorance and stupidity.
Ignorance is not knowing any better.
Stupidity is knowing, yet doing it anyway.

Years ago my first four wheel drum Dart would go through spells of premature rear wheel lock-up. I discovered that the adjuster plugs were missing courtesy of my local garage, and moisture would cause grabbing for the first few stops of the day. This would be more pronounced when a wheel cylinder was leaking, or wet weather conditions were present.

My solution was to learn how to service my own brakes.

Brake Bias is just that, a bias of braking effort to one wheel or axel where a greater force is applied to one wheel or axel over an other for what ever reason causing an unbalance.

Some reasons causing this condition could be hydraulic pressure differences side to side from crimped line, sticking piston in wheel cylinder, different coefficient of friction on the drum due to leaking oil, or moisture build up. Poorly adjusted brakes, broken parts, dirt, different tire pressure side to side...

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Any brake fluid or gear oil on the shoes will cause this.

Brakeleen the shoes after fixing the fluid leak.

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Yeah....Im the one who destroyed this rare, vintage automobile.....

brakleen will not resurrect brake linings that have been saturated with oil. the oil will continue to leech out from inside the linings through heat cycles and reglaze the surface. the linings must be replaced when this happens.

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I've been calling it as i see it for my entire life and that's not about to change. Take it or leave it.

Brakleen will allow you to get organized . Brakleen will get you to the next paycheck.

These are slant cars.

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Yeah....Im the one who destroyed this rare, vintage automobile.....

let's ask jerry.

Jerry, are you so hard up for cash that you cant spring the extra $40-60 for a set of shoes?

are you comfortable driving your kids around with less than perfect brakes?

why else would he ask the question, sandy. Brakes are brakes, do the job right and cry once. slant cars are NOT the cars you want to be riding in when you hit something.

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I've been calling it as i see it for my entire life and that's not about to change. Take it or leave it.

Lets not order new shoes/parts till we take it apart.....this is an occasional problem

Lets take it apart soon and diagnose the source of the problem. (brakleen before reassembling)

Lets put it back together after we are done and go to work in the morning. (Its an occasional problem)

Lets order the parts, if we need any, first thing.

Lets try to get it fixed properly soon......if it needs it.

Lets try to offer useful, non-threatening advice. Not everything is a big huge deal. Its an occasional problem.

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Yeah....Im the one who destroyed this rare, vintage automobile.....

lets also not halfass a brake job on a car that hasnt the best brakes and crash safety to begin with. Respectfully...

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I've been calling it as i see it for my entire life and that's not about to change. Take it or leave it.

Let's let him do the brake job before you can't piss anymore? Please!..

TF

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Even in moderation i am excessive!

You're both (all) right: brake shoes that have been contaminated with oil or grease or brake fluid must be replaced; it's not a "see if brake cleaner will clean 'em up okay" kind of deal; it won't. And this is definitely a safety-critical situation; cutting corners isn't okay.

But it's certainly possible to get this across without whacking anyone upside the head with a rolled-up newspaper, and there's also a good enough chance the rear brakes might be locking for a reason other than contaminated shoes, that if the rear shoes were replaced in recent memory and time isn't so pressing that the repair can be dragged out a little longer, then new shoes don't necessarily need to be on the first parts shopping list (though good quality brake cleaner — I like red-label Brakleen — definitely does).

Best to save the whacking-upside-the-head tone for those who read and willfully disregard straightforward safety advice presented in a non-scolding manner.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

you got it; that is exactly what i was doing, and how my posts progressed.
as a token of my respect for this forum i have removed certain words from my sigline in the hopes that a certain other member will also remove the profanity from theirs in the interest of this family-oriented forum.

jerry be sure and let us know how your brake job turns out.

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I've been calling it as i see it for my entire life and that's not about to change. Take it or leave it.

Well, much to our satisfaction the problem seems to be fixed. Aaron and I pulled the rear brake shoes and decided it would be best to replace them. The front shoe on the left was worn thinner than the one on the right, and all four of them had hairline cracks running vertically down their centers. There did not appear to be any fluid leaks on either side, so the pads looked untainted. The drums were not scored or glazed, so we did not have them resurfaced, we simply went over them a little with some sandpaper.

I did not mention it, but the odometer just recently rolled over 26,000 miles. After replacing the the shoes, we bled the brake lines, adjusted the brakes, and went on a couple of test drives before Aaron headed back to college for his last two weeks this semester. All systems seem to be "GO".

Thanks for eveyone's input,
Jerry

_________________
There's a difference between ignorance and stupidity.
Ignorance is not knowing any better.
Stupidity is knowing, yet doing it anyway.