Front drum brake issue

[Examrp]

I’m having an issue with the front drum brakes on my 63 Dart, they are getting tight after driving several miles. The brake pads are pushing off the top pin and causing the pads to drag on the drum. To fix the problem I crack the bleeder value the wheel cylinder pistons will move back in and then the pads are in the correct position again. I have new brake components (Cylinders, pads springs etc.) and I continue to have this issue.

The picture that is included, the pad is pushed off the pin just a little bit. It usually is off further.

Any idea on why it would be pushing away and not pivoting on the top pin.

Thanks

 

[RustyRatRod]

Do you have the leading and trailing shoes in the correct positions?

 

[cudamark]

I'd say your master cylinder piston isn't returning back all the way when you release the pedal. Wrong length push rod?

 

[Bewy]

Should have a residual line pressure valve for that era of drum brakes, usually located in the outlet of the m/c if it is the original single m/c. It maybe faulty, holding excessive pressure. Odd though that it only affects one brake shoe. Weak return spring [ white ]?

The right hand brake shoe. Might be the pic, but the lining seems to have a gap between it & the shoe.

 

[RedFish]

If the brakes were properly adjusted the shoes wouldn't move near so far to make brakes. A flexible hose failed internally can act like a check valve restricting fluid travel.

 

[Examrp]

Thanks for the thoughts. The shoes are in the correct position. I will check the lines to see if some thing is restricting flow.
i do have a new master cylinder.

Thank you

 

[Inertia]

Do you have to pump the brake pedal a coupla times to get resistance on the pedal, or is the pedal firm, and very close to the top on first push?

 

[Examrp]

Do you have to pump the brakes to get resistance on the pedal, or is the pedal firm, and very close to the top on first application?

The pedal will get very firm after driving awhile. That is when i know that the pad is not in the correct place.

 

[Inertia]

The pedal will get very firm after driving awhile. That is when i know that the pad is not in the correct place.

I Read that, now please answer my questions. Thnx.

 

[67Dart273]

The pedal will get very firm after driving awhile. That is when i know that the pad is not in the correct place.

I think this is an incorrect assumption. I think you have something in the system retaining pressure. Either the master is unable to return, releasing pressure into the reservoir, AKA wrong/ misadjusted pushrod, whatever that might be, restriction in the system or something so bad it is sticking.

Try, after you have driven far enough to create the problem, crack the master cylinder tubing, or better the wheel bleeder, and see if you have a release of fluid under pressure

I would think this could even be something old / gummed up such as in the warning light piston

I supposed it could be that a shoe is warped, made wrong or more likely lining. Maybe the shoes were "arced" that is ground on an arcing machine and someone got one of them clamped in wrong. Only way to tell that I can think of is closely compare those shoes to the other side, after trying to eliminate other causes, and then gamble on a new set of front shoes.

 

[cudamark]

Thanks for the thoughts. The shoes are in the correct position. I will check the lines to see if some thing is restricting flow.
i do have a new master cylinder.

Thank you

Stock single master cylinder, or, upgraded dual? Either way, do as 67dart273 posted.....take the brake line loose at the master cylinder for the front brakes to see if the wheel cylinder pistons allow the shoes to return to their post. An easy way to test this is to have your car on a slight slope where the brakes are hot and tight and the car won't roll on it's own. Place a wheel chock a few inches from a wheel and release the e-brake and have the car in neutral. Crack the brake line loose at the master cylinder. If the car now rolls toward the wheel chock, the master cylinder is holding pressure. If the car still doesn't move, there's restriction somewhere else further downstream in the lines.

 

[str12-340]

please, pads on discs, shoes on drums. Thanks

 

[Demonracer]

Just because the MC is new does not mean that the piston is not returning to the neutral position when you step off the pedal.

 

[clementine]

The 4 min mark


just an idea

But then look at 18 min mark....

 

[MoparLeo]

Show a picture of the entire brake assembly.
Properly adjusted the shoe can't come off of the top anchor pin. There should be very little shoe movement when adjusted properly they will drag slightly.The play is taken up at the bottom of the shoes the tops should have very little travel.
It actually looks like a part is missing.
There is supposed to be an oblong washer that holds the top of the shoes against the anchor pin.
Look in section 5 of any Factory service manual showing front drum brake diagram and you will see the part.

 

[str12-340]

It actually looks like a part is missing.

yep... absolutely correct!!!

 

[townsend]

Just discovered something interesting.
The oblong washer or as Chrysler calls it a plate does not appear in the Chrysler parts catalog for Valiant and Dart cars with 9 inch brakes until 1968.
So it looks like the plate that holds the top of the shoes against the anchor pin was not used on the early A bodies.
If you take a close look at the Valiant pictures of the brakes in the 1963 factory service manual, the plate is not there.

 

[Inertia]

I'm pretty sure there is no oblong washer/plate on the early? 9"".
There is no shoulder for that piece to sit/center on like the 10 inch.