73 Soft Pedal Learning Process

[Steve340]

The pictures were not great but the drums seemed scored and have some weird marks.

 

[Challenger RTA]

The proportion valve does go bad

 

[Ricks72Chlgr440]

Yikes, my 72 Challenger was tough to stop because it had manual brakes with self adjusters.

However, it did stop. The pedal was just high and hard with little feel compared to the regular power brake cars I usually drove.

I am going to bleed but first I am going to see what adjusting my power booster pushrod wil do. It is a brand new booster; I am not sure the shop did the adjustment when they put the MC on. I don't have the tool so I am going to figure out a way to measure the MC bore depth. I want to do this with the MC in the car. At least this will eliminate the possibility this is the issue.

I had an A body car with power brakes that I replaced the MC in. The pedal went almost to the floor before the brakes engaged. I pulled the master away from the booster and lengthened the pushrod. Worked great for a couple of days. As I was driving once after that and applied the brakes the brakes locked up tight. I shortened the rod a little and all was good. Think the master still had some air and the rod was just a bit too short. My experience anyway!

 

[Challenger RTA]

Classic Industries, a rear brake adjustable proportioning valve,

Post a picture of the brake parts that are installed.

 

[Cav73]

Post a picture of the brake parts that are installed.

If you go to post #4 in this thread, on page 1, I have provided photos already that may be helpful. Please let me know if you need additional photos. There are a couple of the metering valve and the Wilwood adjustable proportioning valve I had installed.

Right now the fluid level in the MC is good - I thought it might be leaking into the booster. But it has held steady for a few days since I topped it off. I have a booster pushrod gauge coming and once it gets here I will separate the MC and booster and make any needed adjustment with the guage, and check for leaks.

I remembered recently that I bought this MC a long time ago and provided it to the resto shop that did the brakes.

I last fired up the car and moved it a week and a half ago. At that time, I verified that I do have brakes - it is just that they do not grab until my foot is very close to the floor. For that reason I suspect the booster pushrod. But I won't know until I take a look at it.

 

[Cav73]

I had an A body car with power brakes that I replaced the MC in. The pedal went almost to the floor before the brakes engaged. I pulled the master away from the booster and lengthened the pushrod. Worked great for a couple of days. As I was driving once after that and applied the brakes the brakes locked up tight. I shortened the rod a little and all was good. Think the master still had some air and the rod was just a bit too short. My experience anyway!

Thanks on this! I ordered a booster pushrod gauge because I want to try and get it right the first time and not have to take it apart again. What I am seeing online is necessity to make sure there is a .010 gap, and I have feeler guages for that. Hopefully I can just move the MC forward without screwing up the lines. If the MC is leaking, well that is another story. And of course the fluid could damage the rubber parts in the booster.