Customs Original 1951 Mercury 4-wheel drum brakes.

I just got a 1951 Mercery 4 D Sports Sedan and I the process of making it road worthy. The car is stock and original but has not run in over 10 years and then I'm not sure how well it went or stopped. Currently replacing all brake lines, metal and rubber, wheel cylinders, and the master with a dual unit (mustang II, 1976) using the Fatman Fabrications bracket. Will be installing 10 lbs Residual Valves in each system. There is no power unit so no power brakes.
Question - How well with this thing stop and did I make a mistake going with the original drum brakes and a manual dual master cylinder?

 

Just match the dual master cylinder bore with what the stock single master bore. I would also use a 4 wheel drum master cylinder, late 60’s Mustang or Nova. The Mustang II is a disc/ drum master.

 

I’m gonna run my drums.

It should stop like a 51 Mercury.

I’ve had a few ford trucks that used the same size shoes. Stopped fine.

 

I think the bore is the same and the Master cylinder I'm using is for the disk front, and drum rear, but I think the only difference is the size of the reservoir. It was the one recommended by Fatman Fabrications for their bracket. Do you know of any other difference between the dick/drum and drum/drum master cylinders other than the reservoir size?

 

I run my drums too!

 

Most of the dual master conversions on '49-'51 Mercs I've seen position the new master foreword and next to the left exhaust manifold. I would provide a good heat shield to protect the master.
The M11 master has a 15/16" bore which will result in slightly less pedal effort, but at the expense of more travel, so make sure you can can fully bottom out the master before the pedal bottoms out.
Check for an internal residual valve behind the rear outlet seat, which will save you installing a 10lb inline to the rears.
The M11 disc/drum master, as well as many others, work fine on a drum/drum system as long as the larger fluid reservoir feeds the front brakes.

 

I’m working on this.
Will test fit the engine before finalizing

 

Thanks for the great insight. Yes, the new unit is going in close to where the stock unit was and I do plan to install some type of heat shield. Now sure how to check for this "Check for an internal residual valve behind the rear outlet seat"? Thanks again.

 

I see your design has the lines coming off on the engine side and you are keeping the unit level compared to the Fatman Fabrications bracket. I'll have to see how things go when I get into the install. Thanks for the great photo.

 

1 inch bore like the original
With the lines on the inside I have room to level it out.
Still in the design phase

 

I had lots of brake fade, so for the cost of new drums and shoes I could purchase the disc brake conversion. I’m running the 1976 master cylinder with the fatman bracket. It’s been over 10 years and I haven’t had any problems.

 

You are doing some of the things I was thinking about. Good job.

 

I might go that way eventually but I have to get the thing up and running first. Thanks for the insight. I think for now I'll just go slow. With a whopping 112 hp slow might be my only option.

 

Some drum brake master cylinders have residual valves built in....

 

How can I tell if they are built in?

 

I would not worry about DRUMS. Semi tractor-trailer rigs still use drums. They stop.

Ben

 

Daily driver in Ca traffic to boot.......wow you're up to 20 posts .

 

To check for internal residuals, take a small diameter object and GENTLY insert into the outlet ports. If you feel resistance and cannot easily go into the bore, you found residual(s).

 

While I don't have a problem with drum brakes, Semi tractor have been moving to disc brakes for the last 10 years or so. The industry talked about disc brakes for probably 30 years and now it is happening.

 

THANK YOU and I'm glad I asked.

 

The 14,946 threads asking why my new brakes do not work, helped convince me to just rebuild the stock brakes on my 51 Coupe. It's simple and it works very well.
One of the main issues with drums is making sure the baking plate pads (the shoes slide on these pads and they need to be greased) are not grooved. Most of the time the grooves can be smoothed. If they are really bad, they need to be welded up and the pads restored.

 

See if a piece of wire will go thru the port in the master cylinder....If it goes thru no residual valves....

 

How long ago did you buy the fat man bracket? I was told they didn't make it anymore.

 

Took a lot of pictures of the fatman bracket last time I had it apart. Too bad i didn’t take any measurements. But it shouldn’t be to hard to make.