This booster work with dual reservoir master cylinder?

[Sir Patrick]

Wondering if I can swap out this single res to a dual res master cylinder- drums all around, while keeping the original booster?

And if I can, which one is suggested?

Thx in advance- not getting much reliably in my searches...

 

[Mike66Chryslers]

If you are sticking with drum brakes all around, you can keep that booster and swap masters. One for a 1967 C-body will work fine.

On the new MC, plumb the front outlet to the rear brakes. You can use a short piece of line with a union. Plumb the rear outlet into your existing distribution block, and plug the unused port on the block. There are also cleaner looking but more expensive plumbing solutions which involve replacing your distribution block.

 

[Snotty]

A lot of people will tell you to not do it. I did and have had no problems.

 

[Sir Patrick]

Awesome- Thx guys!

 

[Mike66Chryslers]

A lot of people will tell you to not do it. I did and have had no problems.

View attachment 370440

That is a disc brake MC. It does not have a residual pressure valve on the front circuit, which is needed for drums. Or else you swapped to discs but kept the drum booster. I did that before and my original 383 produced JUST enough vacuum to make the brakes work. Then I swapped-in my 451 which did not, and it was definitely dangerous, so I had to install a proper disc booster. So either way, don't do what you have done.

 

[Snotty]

Didn't take long....

Yes, I swapped to disks. Yes, it's been 12 years. No, I have had no problems.

 

[Mike66Chryslers]

Wondering if I can swap out this single res to a dual res master cylinder- drums all around, while keeping the original booster?

And if I can, which one is suggested?

Thx in advance- not getting much reliably in my searches...

View attachment 370439

BTW, I see that you are missing the metal heat shield over your rubber steering coupler and the rubber is starting to dry out and crack. It's relatively difficult to find replacements for these now, and heat from the exhaust manifold beside it will bake the rubber, so you should reinstall that heat shield or find another one sooner rather than later.

Somebody (Bouchillon I think) sells an aluminum replacement for the rubber one, but they aren't recommended for 65-66 cars. The steering column doesn't line-up with the steering box so you NEED the flex of the rubber coupler.

 

[Sir Patrick]

Ordered-

Advance Auto Parts - Down for Maintenance

 

[Mike66Chryslers]

Ordered-

Advance Auto Parts - Down for Maintenance

When you get the new MC, make sure it has the residual pressure valves installed in the outlets before you install it. I've got ones before that did not and I had to add them.

One of the outlet ports will have 1/2" and one 9/16" threads. In order to install standard-size brake line fittings, you'll need the following adapters (Weatherhead part numbers):
7909: 5/16" (1/2-20) male, 3/16" (3/8-24) female
7910: 3/16” (9/16-20) male, 3/16" (3/8-24) female

If you do the plumbing as I did, you would route the front brake circuit (rear outlet on the MC) to the rear port on the distribution block, where the rear brake line was removed from, because that uses a standard-size fitting. Then you's need to put a plug in the top port, where the old MC connected to. You also need a union to connect the front MC port to the rear brake line which was removed from the brass distribution block. The part numbers for these are:
131X4 1/4" inverted flare plug (for top of distribution block)
302X3 3/16" inverted flare union (plumb existing rear brake line to front port on MC)

 

[Sir Patrick]

BTW, I see that you are missing the metal heat shield over your rubber steering coupler and the rubber is starting to dry out and crack. It's relatively difficult to find replacements for these now, and heat from the exhaust manifold beside it will bake the rubber, so you should reinstall that heat shield or find another one sooner rather than later.

Somebody (Bouchillon I think) sells an aluminum replacement for the rubber one, but they aren't recommended for 65-66 cars. The steering column doesn't line-up with the steering box so you NEED the flex of the rubber coupler.

Thx man! I had no idea.

 

[Sir Patrick]

When you get the new MC, make sure it has the residual pressure valves installed in the outlets before you install it. I've got ones before that did not and I had to add them.

One of the outlet ports will have 1/2" and one 9/16" threads. In order to install standard-size brake line fittings, you'll need the following adapters (Weatherhead part numbers):
7909: 5/16" (1/2-20) male, 3/16" (3/8-24) female
7910: 3/16” (9/16-20) male, 3/16" (3/8-24) female

If you do the plumbing as I did, you would route the front brake circuit (rear outlet on the MC) to the rear port on the distribution block, where the rear brake line was removed from, because that uses a standard-size fitting. Then you's need to put a plug in the top port, where the old MC connected to. You also need a union to connect the front MC port to the rear brake line which was removed from the brass distribution block. The part numbers for these are:
131X4 1/4" inverted flare plug (for top of distribution block)
302X3 3/16" inverted flare union (plumb existing rear brake line to front port on MC)

Appreciate all that info for the install- you just saved me a ton of time, thank you.

 

[Davea Lux]

Wondering if I can swap out this single res to a dual res master cylinder- drums all around, while keeping the original booster?

And if I can, which one is suggested?

Thx in advance- not getting much reliably in my searches...

View attachment 370439

That is a midland drum brake booster that was designed for either single or dual or master cylinders. It has something like 25% less braking boost than the dual diaphragm booster used with disc brakes. The car will still stop with discs using this booster, just not as well as it should.

Dave

 

[Polara_500]

When you get the new MC, make sure it has the residual pressure valves installed in the outlets before you install it. I've got ones before that did not and I had to add them.

How do you check for the residual pressure valve?

 

[Mike66Chryslers]

How do you check for the residual pressure valve?

Shine a flashlight into the small holes in each outlet port. If you can see deep inside the MC then there isn't one, but if it looks like something is blocking the port then there is one. If you're still not sure, take an unbent paperclip or piece of wire and poke it into the hole. If it doesn't go in very far, then it's hitting the RP valve.

If the MC did not come with RP valves, you can install them, provided that the MC was made with press-in brass tubing seats. (I recently got a new Cardone MC that had the seats machined right into the cast iron so it was impossible to add an RP valve. Cheapskates! I'd need to install 10psi inline RP valves to use it.)

Thread a screw into the hole and carefully pry the seat insert out with some pliers.

The RP valve installs like so:

Then reinstall the brass insert and remove the screw. (In the following pic there is another RP valve sitting on the bench so you can see what they look like.) When you install the Weatherhead adapter I mentioned before, it will finish pressing the brass insert the rest of the way back into place. Just go slowly to make sure the insert is not in there cocked.

(Disclaimer: I stole all these pics for this how-to from other websites.)

Now you're going to ask where to get the RP valves. You could steal them from an old MC if you have one laying around. I asked at a local rebuilder's shop when I was getting a booster overhauled and he gave me some.

 

[Big_John]

The car will still stop with discs using this booster, just not as well as it should.

It should still stop, just there will be more pedal pressure. Possibly not a bad thing...

 

[Mike66Chryslers]

It should still stop, just there will be more pedal pressure. Possibly not a bad thing...

Make sure you can still lock the brakes up if you stand on the pedal. In my case I could not. A couple times I came close to rear-ending someone on the highway that cut in front of me. My brakes didn't have enough WOAH!

In this case it's a moot point. The original poster is just looking to upgrade his drum brakes to a dual reservoir drum MC for safety.

 

[Sir Patrick]

Shine a flashlight into the small holes in each outlet port. If you can see deep inside the MC then there isn't one, but if it looks like something is blocking the port then there is one. If you're still not sure, take an unbent paperclip or piece of wire and poke it into the hole. If it doesn't go in very far, then it's hitting the RP valve.

View attachment 370492

If the MC did not come with RP valves, you can install them, provided that the MC was made with press-in brass tubing seats. (I recently got a new Cardone MC that had the seats machined right into the cast iron so it was impossible to add an RP valve. Cheapskates! I'd need to install 10psi inline RP valves to use it.)

.

Residual pressure valves came with the master cylinder! Already installed. Used your method to check- thx. Glad...

 

[Mike66Chryslers]

Make sure the pushrod coming out of the booster is adjusted correctly. Get a small ball of plasticene, steal some PlayDough from your kids, whatever. Stick it on the end of the pushrod and then push the MC all the way onto the booster. Then remove it and see how much the plasticene is smushed. The tip of the pushrod should touch or almost touch the end of the piston in the MC but not be pushing on it. If it needs adjustment, hold the knurled part of the pushrod with pliers and turn the adjuster with a wrench. Then recheck.

Route the lines to the MC with it dry, then remove the MC and bench bleed it before installing for real.

 

[Polaraco]

Thanks Mike. I had some strokes and forgot a lot of stuff. After 6 years I'm finally getting back on my 62, I had an MSD EFI sitting in a box for 3 years I finally installed. I got a heck of a deal on it so I couldn't pass it up. Now I need to improve the stopping. I have 4 wheel disc, but it doesn't stop like it should.

 

[Polaraco]

Hey Mike. Have you thought about drilling a hole in the partition inside the master? You need extra fluid in the rears with 4 wheel disc. I was thinking about that, but drilling it too low as to maintain the dual integrity.