I finally figured out that my brake pedal is not coming "up" because the push rod inside the master cylinder (or brake assist unit) is TOO SHORT. My brake pedal doesn't even hit the rubber stop under the dashboard, it's stopping because it's hitting inside the M/C I think. These are 4-wheel power drum brakes. This is probably not an original M/C as I haven't been able to ID the numbers on it anywhere (5480485).

What's up with that? Help is needed with this one.

Pete
68 convertible

I know in 1970, they had two different sized push rods. One was longer than the other. When I was rebuilding my master cylinder, the company which rebuilt it asked which type of rod I had. Not knowing that there was a difference, I said the stock one that came with the car. Then he explained there were two different sizes. If you look at the area where the rod goes to the master cyl., the long rod one has a deep hole where the rod goes into. The shorter rod has a very small dimple where the rod goes. Chances are you might need the longer rod for your application. You might want to try and call some brake rebuilding places or go to a junk yard and pull some m/c's off the cars.

I have just the opposite problem with mine the pedal comes all the way back up but it goes right to the floor to stop the car. the car stops but the pedal is to the metal. did 3 brake bleeds complete rear rebuild with new cylinders. no leaks anywhere. when i bleed the brakes the fluid does not "shoot out". but there are no bubbles. I guess my next thing is a new master cylinder.
I do not know where to go from here

Sounds like you guys need to trade smile.gif

Chester, you might want to bring the car someplace or rent what is called a Pressure Bleeder. There is a small container, similar to a keg, which is filled with brake fluid and connects to an adapter where your master cylinder cover goes. The "keg" has a bladder inside it which gets filled with compressed air only up to about 30 #lbs or so. I also see that you have a 69. 1969 and 1970 cars with disc brakes have a metering valve which in order to bleed the front brakes, you need to hold in the little button on the rear part of the metering valve. This valve is located directly under the master cylinder and looks like a round cast iron slug. It has one line that goes into the front of it and one that comes out the side. This could be your problem as to why you have no brake fluid "shooting out". To pressure bleed the system, hook up the pressure bleeder and then go about your normal brake bleeding process with the furthest to closest to the master cylinder. No need to worry about the level of the brake fluid as the brake fluid that is inside the "keg" keeps a full level in the master cyl.

Hope this helps.

graemlins/beers.gif

I was able to get some relief by getting under the dash and pulling the clevis pin out to free the brake pedal. I was able to turn the clevis out enough that it brought the pedal up to a reasonable height. I don't have a lock nut on that adjustment, and I'm guessing that over time, the rod in there just turned and turned until the pedal was low.

Now if only I could bleed brakes.