I have 10 3/4 front discs and 10 inch rear drums. I want to go with manual MC and I bought the 4 bolt to 2 bolt adapter. What is the proper diameter MC? I already have an aluminum 1 1/32 MC. Also with the adapter can I use the same pushrod or does it need to be longer?

Thanks

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Sweet Emotion

I am using a 1 1/32 aluminum master (IIRC I asked for a 79 cordoba ?) with the skinny A body 8 3/4" rear 10"x1 3/4" drums in the rear and the KH 4 piston calipers in the front on my 71 duster. Also using the ARengineering adapter.

I used the same rod as I had with the stock iron master (9" drums all around).

I like the firmer pedal feel. There is no "proper" MC diameter to use, just tailor the diameter so that pedal travel/firmness is to your liking

The bigger bore, the less pedal travel and firmer it is. The smaller bore, the more pedal travel and softer the pedal is. 15/16" is stock for 9" drums on A bodies, 1 1/32" were used in heavier cars and trucks with bigger breaks. I wouldn't go past 1 1/32" in a street car. I've heard of bore sizes all the way up to 1 1/8".

FYI, if your going to a parts store to pick up a master, using an applicaiton like 79 cordoba for a 1 1/32" unit, make sure to take a magnet with you. The original ones were aluminum, but the new aftermarkets were cast iron. Also, these new aftermarkets could of been turned in for cores, so you can get an iron rebuilt one as well. I would just splurge and spend the $100 for a new MP aluminum unit to avoid the parts store headache, it took me like 3 tries to get an aluminum one.

Thanks. I already have an aluminum 1 1/32 MC but I want to rebuild it. I pulled it from a JY and it has no pushrod.

First, I'm having trouble finding a rebuild kit.

Secondly, how do you get the pushrod out? My old 4 bolt cast iron MC has the pushrod but I'm having trouble getting it out. Is it seated with a rubber grommet? Do I just pull real hard or what?

Thanks

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Sweet Emotion

Pull really hard.

I used a aluminum MC from an '80 Volare with manual brakes. It worked fine with the stock '65 Dart push rod. The manual MC is differant then the power MC. It has studs attached to the MC. The readily available 4-to-2 adapter may not work correctly. I built mine from 3/8" sheet aluminum for $1.50 and a hour of my time.

The rubber bushing and the rubber push rod boot are not serviced seperately. You need to buy a MC rebuild kit to get those parts. Mine came from a rebuild kit for a '65 single pot master cylinder. I have not located a source for the spring that goes over the rubber boot.

Rebuilt master cylinders are like $20-30 from parts stores, are you sure your going to find a kit for cheaper then that?

Of the two or three master cylinders I bought from local parts stores, the rubber grommet holding the rod in came in a small bag in the box with the master. One of the bigger sites was reproducing these, magnumforce or bigblockdarts maybe?

To remove the rod, clamp the rod in a vice and hammer on the flange.

The MC that I used came from a non-running '80 Volare, hench free. The OE bushing was missing and the old one from my '65 had torn. The rubber boot from the '80 volare didn't work correctly and the '65s had detoriated over the past 35 years. The '80 doesn't have the boot spring and the '65s had rusted and broken into multiple rings. The $10 for the rebuild kit was worth it to me.

Do not pound on the flange! All you need to do is pull hard. They are not in that tightly.

I got the pushrod out by placing the shaft inside a loose vise such that the piston was beneath the jaws. I used a rag to prevent marring and I use an aluminum locking snap ring like the ones rock climbers use. I put the snap ring through the eye in the pushrod and the slipped a 4 foot pipe through the snap ring. Then using the leverage I pried upwards on the pipe and it came out.

I completely disassembled the aluminum MC and completely cleaned it up although it was pretty clean to begin with. I can't find the rubber seals for it so I'm reusing the old ones. We'll see if they last. Then I put the aluminum ARengineering adapter and the boot over the pushrod in the correct orientation. Then I stood up the MC with the piston facing upwards. I suspended the pushrod so it is in the piston receiving hole and I used RTV to glue the rod into the piston. This seems like the most rugged solution and believe me it's not coming out easily. It's flexible but because of the grooves in the piston and the pushrod it's definitely secure. Bottom line is I know where to get another aluminum MC if I need it. I know it's not the conventional way but I believe it will work. I tried using 5/16 rubber se as a grommet but it wasn't seating well so I opted for the high temp red RTV.

I will install it tonight.

Thanks

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Sweet Emotion

Correction I meant to say I tried 5/16 rubber hose for the grommet.

Also all the rebuilt MC's I have seen are cast iron and I want the aluminum one which is why I want the kit. Pep Boys is the only place that can get me a kit. It cost's 40 bucks and they actually list it as 1 1/32 diameter. But I'm on the cheap right now so I opted for the method described.

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Sweet Emotion

Pound and hammer are two different things....

And if all thats required is a hard pull, then the grommet wasn't doing its job because you would of easily been able to pop the rod out by prying up on the pedal with your foot.

You can do without the grommet alltogether. Even with no grommet, the brake light switch/bracket will prevent the pedal from coming up far enough for the rod to come out of the master cylinder. So unless someone carelessly pried up on the pedal hard enough to break the plastic switch or bend the bracket holding it, the rod isn't going anywhere.

I would NOT rely on the brake switch alone to keep the pushrod in the MC.
The switch bracket is only whimpy sheetmetal.
I've had my big foot accidentally get hooked under the brake pedal in a panic situation. Unexpected things happen under those condition. GET THE GROMMET.

Some years ago I was able to order it and a new boot from MaMopar but those parts may be NS1 today.

I have been told by several people to remove the residual valve from behind the flared tubing seat in each MC outlet. These were originaly in there to keep pressure on drum brake shoes even when not braking. They are not needed anymore because of the springs that are now in all drum wheel cylinders. Any one else know about this? I have not done it myself, but am getting ready to put disk brakes on the rear, and will want to remove the residual valve for sure. Another concern is that drum/drum applications had a residual valve for both front and rear, while disk/drum had the vlave only on the rear. When they rebuild these things, I am not sure how careful they are to match the application precisely. Do the rebuild kits include new flare seats for the out let fittings? I think the only serious car guys who use the residual valve these days are street rodders whose MC is down low on the frame. In this case they prevent the fluid from draining out of the lines and back into the MC.

My guess is that the newer MCs don't even have these valves to begin with. I have an unmodified 84 Dodge truck MC (disc/drum) on my '64 Dart with rear discs and have no dragging problem on the rears.

Lou

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