Master cylinder to booster question and maybe more as it goes on

[darbgnik]

Ok guys. So I am finally getting around to installing the disc brake kit I've had in boxes since before I started getting the body work done.

The kit is a Right Stuff Detailing kit, just for the calipers, spindles, rotors etc. I bought the master separately as well as one of the new reproduction dual diaphragm boosters. The master is a Rock Auto Centric 130.63055.

The piston on the master is sticking out past the flange 1/8" give or take. So the push rod in the booster, which is already adjusted as short as possible, contacts the piston before mating the master to the booster.

My question is: is that 1/8" sticking out part of the travel? Meaning if I push them together as is, is it going to be applying the brakes?

And if so, do I just shim the master away from the booster? As I cannot make the push rod shorter.

Thanks.

[PlainfieldCharger]

When I purchased my car it had that kit on it. I wanted an oem restore so I changed it out right away. It had a (home made) aluminum spacer to stop the rod from "applying the brakes" which it was doing by the way...as the rod was still tight...which it was caused me to have to fix right away..

[b5blue]

We are gonna need pics to understand what you have and what may be wonky.

[darbgnik]

When I purchased my car it had that kit on it. I wanted an oem restore so I changed it out right away. It had a (home made) aluminum spacer to stop the rod from "applying the brakes" which it was doing by the way...as the rod was still tight...which it was caused me to have to fix right away..

Thanks for the reply. Just to be clear though, the repro booster and the master were not part of a kit. I bought them separately and fairly recently.

I guess the basics of the question is, and I watched some videos of the subject and noticed on all the disc brake master cylinders, the piston was not flush with the mounting flange,  they all seemed to stick out at least an 1/8 inch. My question is, is this the resting position, and by pushing the piston flush with the mounting flange are you starting to apply the brakes?

As I mentioned previously, shortened all the way, the rod on the booster pushes the piston in at least flush. Meaning the piston on the master is depressed already an 1/8 or more when they're mated.

[John_Kunkel]

Some factory installations had a spacer between the booster and the MC; called a "hub" in the diagram below. P/N 2467578.

The type of MC that retains the pistons with a bottom screw will have the rear piston protruding from the MC body.

[PlainfieldCharger]

Even with the aluminum spacer I could not get mine adjust rod short enough either..the spacer installed was not thick enough to get adjustment. Hope this helps.

[b5blue]

Also the black steel reinforcement plate mounts between the booster and firewall. See if "The Ram Man" has one to sell.

[darbgnik]

Continuing on guys. Thanks for the responses.

I ended up digging up the MBM instructions. You know, the ones they didnt include with the booster.... Anyways, all I had to do was remove the jam nut on the booster rod adjustment bolt.  Now it's just a tad too short, but you are supposed to leave a gap.

Now to see how the rest pans out!