DragStuff

I've heard of people using Dodge type master cylinders for their disc brake set-ups. The word is they're just like a Strange unit without the price tag. Anybody have any info on this?

We have an article in the tech section -

http://www.dragstuff.com/techarticles/R ... CylPN.html

Thanks. Any special modifications to get them into a non-Chrysler application?

For a chevy you'll have to slot the mounting holes a little bit. You should also make certain you have some kind of pushrod retention device, you don't want the pushrod to drop out if it's too loose.

John, I unthreaded the push rod so it fits snugly how much play should be in teh rod if any?

I set mine up with just a tiny amount of play, not much. Did you rig up something to retain the pushrod to prevent it from coming out of the master cyl just in case something loosens up? That's important!

John, I unthreaded the rod and reset the locknut, do I need to safety wire it? I'll try pulling the brake pedal out to make sure its in there snug enough.

I do have another question. My dad has a 71 nova, 4 wheel drum brakes. Is there a cheap way to convert to disk? Will the Mopar master cylinder work on the drums? Is it worth it to convert to disk?

As I mentioned, some method to positively retain the push rod in the master is a VERY good idea, lacking one has lead to lots of wrecks. For example, car does a huge wheelstand, car slams down hard but driver decides to run it out the back then realizes no brakes. The firewall etc. flexed enough to drop the rod out. Unexpected stuff can happen. That's why a retainer is very good idea. OEM stuff has a little rubber boot thing that does this. I made something more sturdy. This is just a piece of steel strap with a hole drilled in the middle of it with clearance so the push rod will pass through without rubbing. It would not hurt to put a little blue loctite on the pushrod nut, safety wire might be a real bitch to work with in that location.

Regarding the drums on your dad's car, typically most people switch to disc to save weight, especially if you're using racing type thinner rotor type brakes. I'm not sure what the savings would be, it's been an long time since I weighed drums.

The stock car guys have some cheaper methods to do the swap, but you won't save as much weight. They use the Malibu metric style calipers (wilwood makes these in aluminum now) and stock car rotors with stamped steel hats for the rear. These often use a weld on bracket caliper bracket. There are less options on the front, I'm not sure there is a "cheap" way to swap those over to something light.

You can go pretty darn fast with drums, they will work fine other than the heavier weights.

What's he do with the car?

Note to Self: Make a new one of these out of aluminum

My dad plans on dragging the car. Its a 406/th350 10bolt, I am guesstimating the car to be in the low 11's. Its a 71 nova. We just gutted it, put in an 8pt cage, frame connectors, then fixed a whole lot of stuff, body mounts where original, so we switched to aluminum. Fuel Cell. His current Master cylinder goes straight to the floor, he has to pump it quick to stop, so that needs changed before the trip to the track. I put the dodge MC on my car, was thinking of doing the same on his, but didn't know if it would work with the drums. We changed all the replaceable parts on the drums and ran all new lines, again, the old ones looked stock.

I really like the bracket idea, I do believe that is what I will do.

Hey John, I hate to bug you again on this topic, but could you detail this swap. I got one of these master cylinders coming in tomorrow going into a '68 Camaro with a front Wilwood disc set-up. If you could, exactly what is slotted and what are the dimensions of your retention device? Could you show a few more pics?

MMAX wrote:Hey John, I hate to bug you again on this topic, but could you detail this swap. I got one of these master cylinders coming in tomorrow going into a '68 Camaro with a front Wilwood disc set-up. If you could, exactly what is slotted and what are the dimensions of your retention device? Could you show a few more pics?

The mounting bolt holes on the master cyl are slotted a little bit to fit the studs on the firewall. A good round file, or a carbide bit in a die grinder will open it up pretty quickly to fit the mounting studs.

I don't have dimensions of the retention strap or more photos of that, sorry. It's really not that fancy, just a piece of steel with a hole big enough for the pushrod to fit through and bent with an offset to space it away from the firewall maybe 1/2" or so. You don't want it too tight of a hole, just small enough that the pushrod can not move out of the master cyl if it gets loose, or the MC sticks.

Well, I got her done. Had to slot the holes on the new cylinder quite a bit. Didn't really enjoy standing on my head to get the strap in place, but it looks like it should work.

MMAX wrote:Well, I got her done. Had to slot the holes on the new cylinder quite a bit. Didn't really enjoy standing on my head to get the strap in place, but it looks like it should work.

You should try it with a full funny car cage in the car, what fun! lol Good to hear you got it in there.