First the business, '66 Dart, 9" drum brakes, all new shoes (summer), new master cylinder (summer), and bled the fluid (also summer).

My issue is that when I apply the brakes the car pulls to the left (and turns the steering wheel). The harder I apply the brakes, the more aggressive the pull, also is intensified by lower speeds. Also, my front driver-side wheel locks up (but none of the others) under heavy braking. I'm assuming these are directly related, both issues caused by my front driver-side shoes being out of adjustment. The question is why? They have been progressively getting worse shortly after summer (the car had an issue with pulling before the any work was done) and now it is quite noticeable.

I also have another brake system issue which may be the cause to the (mis)adjustment of the brakes. Since I've owned the car, it has had an issue with the pedal falling half way to the floor when being depressed. Bleeding the brakes fixes the issue but only temporarily. Now, my old master cylinder did go bad, so I thought that was causing air in my brake lines. However, over time the issue persists with this new master cylinder.

I'm starting to think I have a small air leak somewhere in the lines or possibly a wheel cylinder. Does this sound likely to anyone? And is there a best way to find such a leak? Would I start by replacing a wheel cylinder or two (I'd probably change the front passenger side first, then check the back two)?

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'66 Dodge Dart

Probably have a leaking wheel cylinder on wheel that locks up.

Pull both front drums, inspect for fluid leaking and contaminated shoes, inspect both hard & soft lines feeding front brakes for leaks. Also check fluid level in master cylinder.

If shoes are contaminated you will need to replace them.

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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 tips on finding where the leak might be? Last time I tried search for one I came up empty, the shoes and drums looked normal, and I didn't see anything wrong with the lines (though it was just a quick once over).

Should I have someone depress the brake pedal while I look?

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'66 Dodge Dart

NO!
Not when the break drum is removed. You will pop out the wheel cylinder pistons, and generate a big mess.

Look for gummy black stuff on the break shoes & drums, damp dust & wetness around rubber boots on wheel cylinders, and damp looking dust along break lines.

Look for crimped hard lines, and defective soft lines. If you haven’t replaced the soft lines, rather, rubber flexible lines, in the last ten years it is time to replace them.

Is the fluid level in master cylinder much lower in one chamber than the other. This could indicate a leak, or worn shoes on one axel. Generally front brake shoes wear much faster than the rear shoes.

One other item to inspect: have you installed the shoes properly? By that, is the primary shoe (the shoe with shortest lining) in the proper position, that is, facing to front of car. In other words, when looking at your break shoes with the drum removed, the shoe with the short lining faces to front of car, and the longer lining faces to rear of car.

If one mixes up this primary-secondary placement, the break will grab with vigor.

All this is outlined in the Factory Service Manual with pictures.

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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

I've only had the car just over a year so no clue when the soft lines were replaced.

As for black gummy stuff or dust that appears to be wet, didn't see any last time I had the drums off. I did noticed some slightly darker looking dust on the rear brakes from the side with the bleed valve, but the valves were nice and tight.

I just remembered another possible issue. When I replaced the shoes I noticed that the adjuster was bent. The metal piece that spins the adjuster star was bent and not making contact, so I bent it back as close I could. I don't remember which wheel it was on but I'll check to see if they are working. Has anyone had an issue similar to this? Is the exact angle of this metal piece very important?


I followed the FSM when I replaced the shoes, so I don't believe that is the issue.

I guess I'll wait for some of the snow to clear away and get a better look at the brake lines. Then take of the drums and see if I can't spot anything...

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'66 Dodge Dart

It would be a good idea to replace the front wheel cylinders to see if that solves the problem.

Also, inspect the front strut rod and strut rod bushings, a broken strut rod or degraded bushing will cause the car to pull when braking.
DD

A wheel that's out of adjustment will actually lock up easier than a wheel that's in adjustment.

See if the adjuster are about the same length side to side.

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

That sounds like it would take some special tools and a whole lot of new skills (I've never done any suspension work). Lets hope it doesn't have to come to that. Regarding replacing both front wheel cylinders, any reason why not just one (on either side)? Also, any particular recommended part or just whatever the local auto store has?
I had an alignment done less than 6 months ago and the car drives nice and straight (as long as I don't brake).

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'66 Dodge Dart

I was talking about the brake adjusters not alignment.........

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

Wow, I must be loosing my mind, I have no idea why I thought you meant alignment. Oops!

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'66 Dodge Dart

You can get brake hardware kits (springs, adjusters, shoe studs, etc.) for not much moolah. Replacing wheel cylinders in pairs is a good idea. If one cylinder has failed due to age or corrosion, the other is not far behind in crapping out. Cylinders are not expensive.

Inspect the rubber flexible hoses for cracks, stiffness, corrosion, and chaffing. If you find any of these conditions change them out. Your brakes are only as good as the weakest link. Also where you have a 66, you don’t have duel master cylinder. So if one of the brake components fails, the whole system fails, unlike the duel system for 67 and up that provides one axel braking if some part fails.

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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

After a careful inspection today it appears that my front driver side wheel cylinder is on its way out. Since this is my first wheel cylinder replacement a few questions...

Should I bleed the brakes after replacing the cylinder or is that not needed?

The when disconnecting the brake hose, how much fluid will come out (if any), should I be ready to catch it?

The FSM mentions using "sealer putty" around the wheel cylinder. Gasket sealer or is there something special I should be using?

The FSM also mentions several torque specs, how important is getting these right on? I don't think my torque wrench will work well for the space constraint.

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'66 Dodge Dart

If the fluid is old, might as well bleed everything. Otherwise just the wheel cylinder is fine.
It will drain the system if you don't cap it off. I usually use vacuum caps.....
That's new... (or old ?) never bothered with anything here.
What's the spec? I've never used a torque wrench, just go by feel...

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

The flexible lines should have a date code on them unless they are real old, in which case, replace them.

If it were my car, I would replace both front wheel cylinders, and bleed all four cylinders as brake fluid attracts moisture, and should be flushed every several years. As the fluid ages it becomes darker in color to darn close to muck if real bad. Moisture is the prime cause of cylinder failure, it causes pits, and helps to rot the seals along with father time.

Before you round off, and wreck all your bleeder valves, and fittings, pick up a bleeder wrench, and a tubing wrench. These are special wrenches needed to take apart a brake system. You might as well get them now before starting work.

You will need a length, say a foot or so, of clear flexible plastic tubing, and a small can to drain the freshly bleed old fluid into. Using clear tubing allows easy viewing of color & air bubble movement during the bleeding.


Bleeding sequence:
Starting with the wheel most distant from the master cylinder, in other words; first bleed right rear, second left rear, third right front, and lastly left front.

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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

What in the world is a bleeder wrench (other than a very small box-end)?

Thanks for all the info, but I've bled my brakes before (as stated above), all I really needed was answered by Ed, thanks Ed!

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'66 Dodge Dart