67 Cuda Brakes OUT!!!

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pastortom1

pastortom1

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Guys...........

I just flew to NY for a memorial service, and had planned to drive my 67 Cuda while there.

I took it for a spin to McD's for breakfast, and noticed the brake pedal was low.BUT, it seemed solid....just low......I figured an adjustment was in order, or I needed a little fluid.

I left Mc's, and went to the grocery store down the road.....as I parked the car, the pedal went even lower, and ended up on the floor....literally....all the way to the brake light coming on......I could still stop the car with a good push, but it was basically to the floor now.

I nursed it to the parts store and got some fluid........I removed the cover from the master cylinder, and it was down about a half inch or so.....I filled it, and expected to have a little pedal.......NOTHING happened.

The car will still barely stop with the pedal to the floor, so I doubt it's a leaky line......I figured there would be no pressure in that case, and the fluid would disappear............

So, do I have a bad master cylinder? I have NEVER had brakes act exactly like this before..........

What do you guys think? (it's standard brakes too.... no power) :read2:
 
I've had this happen a few times, not in a Mopar. Mine always happened after the car sat a few months. Seems the brake fluid messes with some seal in the M/C and then I had the problem you describe.

Replacing the M/C always fixed it. I wish they had stabil for brake fluid.

Just my 0.02
 
If the master cylinder is leaking on manual brakes, you should be able to see fluid leaking up under the dash where the pushrod comes thru. If there's a dust boot there just squeeze.........
 
6pktogo, you're right. One did leak at the pushrod. The other one did some weird internal bypass and never leaked. That messed me up some.
 
Sounds like you blew a wheel cylinder. Try looking at the back of each wheel for fluid. If the event you did blow one the best thing to do is replace both wheel cylinders on the same reservoir.
 
1 or 2 problems... Definately a tiny fluid leak somewhere that let the pedal go down. The spool valve in the master cylinder has now traveled past some wear/debrie in the bore causing it to fail internally. If you can find the fluid leak on in or out side of firewall it's all one problem right there. If not you'll need to find the leak and stop it
 
I think what you guys have said makes sense...........

The pedal was a little low the last time it was driven. Brakes worked, but the pedal wasn't right.........seems like a pin leak somewhere, wheel cylinder, etc.............

But it has been sitting for months and months, and it's the original 1967 master cylinder............It does seem like after the pedal faded that there is no resistance whatever.........not even from the master cylinder.........

I guess I'd better have the whole shebang done...........

What do you guys recommend for a master cylinder.........I'm wanting to keep the car as original as possible............it's a true survivor.

What should I do? :read2:
 
That is a dual line system so there is no reason to replace the master cylinder with anything newer or different from stock.
 
With the fluid level only being down a little, I would look at the master cylinder as the problem. That said, I would pull all 4 wheels and drums. Look for fluid on the inside of the backing plates. I also like to peel back the wheel cylinder dust covers, if there is ANY fluid between the boot and the piston, REPLACE THE WHEEL CYLINDERS,I replace them in pairs. If one front is bad I replace both fronts. Same on the rear. When all is said and done. If you can get a presure bleeder, I would flush the whole system. JMO
 
If it for sure the MC then you might want to upgrade to the newer, lighter, aluminum MC. I installed one on my cuda and it made a big difference in the brakeing of the car. Mine is non power.
 
Recommend overhaul of the master cylinder. Auto Zone has a M/C rebuild kit (on line) for ~ $30 for a '67 with drums. Get some fine steel wool, or use a small hone, to clean out the bore. Wash thoroughly before rebuilding. It's not difficult to do, though you do get the joy of bleeding the entire brake system when complete.
 
Whether you replace the MC or rebuild it, bench bleed it b4 you put it on. Most times you won't have to bleed at the wheels afterwards, maybe a little to be sure the air's out.
Bench bleed- Put it in a vice, fill w/ fluid, push piston in w/ screw driver or something, hold it in, cover outlets w/ fingertips, release piston. Repeat til air's out.
Waalaa, presto, done-o. (I hope so!)
 
Right you are about bleeding the MC, Speedthrills. I've done the bench bleed with short lenghts of tubing over the outlets re-directed to their respective reservoirs. When you get a solid stream of fluid with each pump, job done.
 
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