Ok, lets reverse this............

Maybe the rears are fine, and the problem is up front.

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

So? Manufacturers often carry different grades of shoes. Carquest has hard as rocks shoes in blue boxes and cheaper, much grabbier shoes in red boxes. All house brand stuff.

And I''l second emsvitil. You have the right size front wheel cylinders? Good master cylinder?

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Joshua

Did cylinder kits in the front. The parts fit the cylinders I had. Seems likely there the right size. All brake shoes came in the same color boxes. I have not sent the shoes to a lab for hardness testing. I've had brakes that you had to stand on to get them to bite. If it were a bite issue I would think I would need to stand on the brakes more to get the rears to lock, but it doesn't take much to lock them. I can't get on the brake hard enough to stop the car quickly without locking rears. What I am trying to say is that I am not in the hard braking zone yet and the rears lock. If the rears didn't lock I think I could get on them more and stop rather quickly. I am thinking about using a hose pinching tool on the rear hose and see if the fronts with bite in with normal hard braking. Now this can't be done without locking the rears.
A bit wordy but it should be clear what I feeling. Whats going on, I don't know.
MC has not been changed. Brakes worked OK but a liitle pull before I started.

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

My thinking is that the fronts aren't biting, you're not stopping and then you lock the rear in an effort to stop...........


Does a 67 have a single or dual master cylinder?

Might be the master if dual or the splitting T if not.


If its a dual master, I'd try switching the lines around and have the portion of the master that's currently doing the front do the rear and vice versa. If the problem swaps front to rear you know it's the master cylinder. If the problem fixes itself, it was probably the master and there was something blocking the front line until you switched it.


Did you get new front hoses? If not, they may be clogged

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

All new hoses. Yes dual MC.

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

I have decided to drop the drum brakes to bite the bullet and move to a disk system sooner than I really wanted. Thanks for the help. Still don't know whats wrong with them but that in the past now.

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

Its not in the past if the rears are not right.....

Did you happen to adjust these brakes before the panic stop testing?

Do you realise that 9" drums will never stop very well and that you may be locking up the rears in an attempt to get them to do things beyond their ability?

What is your plan for rear brakes when you get the discs?

Are you going BBP?

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

Putting in the 8`1/4 rear I have and going to BBP all the way around. Getting 4 new BBP wheels.

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

I'd put a pressure gauge on it to find out where there may be weak pressure. New parts don't mean good parts. If it's the MC, you'll have trouble with the disc brakes also. Besides the MC, I'd check pressure at the ends of all three brake hoses.
The piston in the MC is staged to apply pressure to the fronts first, that's why the front brake line is on the rear port. If the piston is frozen together, pressure will go to the rear at the same time.
You sure the park brake cable isn't sticking, as mentuioned in an above post, and removing freely? If it is parially on, it will act like the brakes are overadjusted.

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Slant Cecil

I have never used the parking brake. I am afaid to in case it sticks. Going to disk brakes I'll need a new MC anyways.

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

did u cut the drums?? (or have them done) How "rough" a finish on them? Ive had prop valves go bad and cause the same thing. As was mentioned before I dont think your car has one. Most 4 wheel drum cars did have a residual pressure valve built into the master. if holding too much pressure in the line it would take less to acivate the brakes when you hit the pedal.