How to diagnose and fix brake issues?

Michael_

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Stock 1969 Dodge Charger R/T 440/727 with disks up front and drums in the rear.

When braking at ~ 40mph plus the rear end pulls to the right side instead of going straight.
The car WOULD get away from me when hard braking at higher speeds.

I've never worked on brakes.
How can i figure out what's wrong?

How likely is it that only the rear drum brakes need adjusting/service?
I have no idea how they work, though. (Need to look it up)

What exactly does the proportioning valve do?
Does it only regulate the front/rear or also left/right brake power?

Yes, i will take a look in the service manual aswell.

I THINK the shop that did the necessary work to register the car in germany (back when i bought it) replaced the brake hoses
but i will check if they look old or new as i read somewhere they can restrict flow when they age which you can't tell from the outside.

To me it looks like the driver side drum brake isn't as effective as the passenger side.
But i'm not 100% sure and i have no idea why.
 

62 Dart Convertible

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Proportioning valve only limits pressure to the rear brakes and has no effect on left/right.
I'd say it sounds more like you have a seized slave cylinder.
If it were me, I'd jack the rear up, take off wheels and slide off the brake shoes.
Have somebody else apply brakes gently while you watch the slave cylinders and see if they move. I'm betting the drivers side is stuck.

Or that perhaps the shoes on the drivers side are saturated in brake fluid or diff oil and not able to apply the friction....
 

davek

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could one of the adjusters be to tight or in wrong?
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bm02tj

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Find a dirt or gravel road or parking lot with nothing to hit then do a couple hard braking stops and look to see what skids first and last
 

MoparLeo

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Just like the first thing to do if have an addiction and want to fix it is you have to admit you have it. Bravo for you for admitting that you do not know about the brake system. This is the most important system on any car. If it doesn't work properly, someone gets hurt or worse.
The brake system should be inspected by someone with more than just a little knowledge about it and a book.
Find a reputable shop that services brake daily. You want to have the people with the most experience working on this system. Not someone practicing with your safety.
The car is 54 years old and some of the brake system components could be that old as well. Everything has a limited life.
The most common cause of one rear wheel locking up is a fluid leak on the shoes. It could be a wheel cylinder or an axle seal. You could just remove the rear wheels and drums and will see it right away.
Now servicing it is another matter.
Always use the highest quality parts you can. Get experienced help, proper information materials, proper tools and don't cut corners. Do it right or don't do it.
Your brakes have to be dependable so price is a secondary concern or should be.
I know parts for American parts are more expensive in Europe but then you have a car that is also very expensive on both side of the ocean.
learn the basics before you ask about things like proportioning valves and such. Even people experienced on these car don't always know what everything does. And that is a part that rarely needs servicing unless it is badly corroded internally. If it is, likely the entire hydraulic system needs to be replaced anyway.
 

PlymCrazy

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Michael,
How long have you owned the car? Has this brake issue always been present during that time? If so, I agree with Dave K something may be installed incorrectly. However if the brakes worked fine at one point and this issue just arose then it's very likely you have a failed component such as a wheel cylinder(as 62 Dart mentioned) or oil seal causing more/less brake function on one side as opposed to the other. - Nick
 

PlymCrazy

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Could also be a seized caliper up front as well. This would likely cause some drag while driving it and the steering may pull to one side or the other even without applying pressure to the brakes.
 

Ron H

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I had an issue with the self-adjuster on the left rear wheel a few years after I had replaced all the hardware. The star lever wasn't fully contacting the star wheel. After trying to get it set properly, still had uneven contact. Replaced the self-adj hardware and solved the problem.
 

Don Frelier

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Proportioning valve only limits pressure to the rear brakes and has no effect on left/right.
I'd say it sounds more like you have a seized slave cylinder.
If it were me, I'd jack the rear up, take off wheels and slide off the brake shoes.
Have somebody else apply brakes gently while you watch the slave cylinders and see if they move. I'm betting the drivers side is stuck.

Or that perhaps the shoes on the drivers side are saturated in brake fluid or diff oil and not able to apply the friction....
If it pulls to the right then it's likely (but not certain)the problem is the left rear not functioning correctly or possibly the right side is locking up to easily.
Both sides need to be inspected.
The left side could be loose adjustment, wheel cylinder stuck or oil on the shoes.
The right side could be a broken retaining pin or a rusted drum or incorrectly installed hardware.
 
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