Technical Juice Brake Conversion, Issues, Help!

I am converting my '28 Model A to juice brakes. I am using the later Ford backing plates 46-48 and all the hardware that goes with them. Ordered new wheel cylinders and pads from Macs. I also had a bracket built that I found here on the HAMB... I cannot find the original thread though. I have attached pics of the master cylinder bracket. The one with the master cylinder is from the original thread and the others are my bracket.

I want to use a dual master cylinder with this setup.

What master cylinder do I need to use? Is there a certain diameter or spec I need to purchase?

Thanks
Vinnie

 

any dual reservoir DRUM brake master you can fab in will work. I am doing the same conversion on a 34 Ford.. Going to use one from a 68 chevelle

 

So different master cylinders don't have different pressure? That's good to know.

 

Yes, the bore diameter will make a difference in applied pressure, and in the amount of travel needed to make that pressure. You should be getting more replies shortly.

 

Find out the bore diameter of the stock master cylinder for a 46-48 ford master cylinder and find a dual drum/drum master with the same bore.

 

If you feel compelled to run a dual master cylinder, why not be period correct and use the 1962 Nash Rambler?



EBay Link-
https://www.ebay.com/itm/1962-AMC-6...382958?hash=item34095ce7ae:g:n78AAOSwOz5cwvqQ

 

I'd like to run a dual master cylinder for the extra safety. I prefer a modern day one. Just was asking if someone knew what modern one would be same diameter/pressure as the 46-48 Fords.

 

Thanks... That is what I am hoping... that there is a modern/new one with the same bore diameter/pressure. I figured this is the place to ask!

 

Then you need one with the same bore size as a '46 to '48 Ford. I don't know offhand what that size is, but it should be easy to find out.

 

Not looking to argue however-
I still run the stock single on my 1953 Chevrolet and have never had any trouble. I have had the car for ten years and average over 2,000 miles a year. I check brake lines and hoses and adjust the brakes regularly if I see an issue I fix it before I take the car out. Brake failures very rarely happen instantly they develop over time.

I don't understand the added safety theory of a dual master cylinder. If you lose a line on a single master you can pump the pedal to stop in an emergency.
When I was going to welding school I was driving a late 80's, Ford Ranger. I lost a brake line half a mile from the school.
I limped it in, however, I had to stop at a (long) light on a hill, the truck kept rolling back even with my foot on the brake I tried to pump the pedal. I had to ride the clutch to keep it from rolling.

Just after welding school, I had a 95 Chevrolet that I lost a wheel cylinder. Same thing I could not stop I had to pump the pedal to get stopped.

Both issues came from a lack of preventive maintenance.

I think everyone has the idea that you have full pedal and full stopping power if circuit fails. If that was the case you wouldn't need to bleed the front and rear circuits separately.

I have heard of people having far more trouble caused from using a dual master cylinder with drums, no brakes, brakes won't release ect...
Then someone avoiding a crash because of having a dual master.

 

Manual brake master cylinder for a '75 AMC Gremlin has an 1-1/16" bore same size as the single that was originally used with '39 up brakes.
Whatever master you use; make sure you have adequate pedal travel in case of failure. Otherwise, your dual master cylinder will be just an illusion of safety.

 

Isn't it early Mustang drum/drum master cylinder the one usually used for this?

 

correct

 

I have never tried the AMC M/C before. Thanks for the info

 

1967 Mustang manual master cylinder bore size is 1 inch, 7/8 inch with power brakes.

 

@RICH B
Any chance that you have a p/n for that 1-1/16" AMC m/cyl?
All I can find is 1" for manual drum/drum, which is what I'm using currently.
Thanks!

 

Try these numbers.
A-1 Cardone 10-1492 Raybestos MC36456

 

Ain't those for front discs?

 

^^^^^Thanks, Rich!
I poured over the Cardone hard cover catalogue this morning, and it showed that number, but no specs. Did you have good results with it?

 

I learned about this master from someone on the Ford Barn. I haven't used one of these yet; but I have used a E-250 (1-1/16") bore master to replace a 1" bore Mustang master stock pedal assy set-up that would not clear the floor when testing in one side failure mode in my '47. The E-250 is bigger physically than I like on the '47 and I plan to get one of these American Motors masters to replace it. I also have the 1-1/16" bore E-250 master on my '35 (with a '40 pedal assy) and it works very well. So I have been satisfied as the 1-1/16" bore size is the same as the early Ford masters and seems to work out good.

 

Disc masters have worked OK on drums for me; I just added external residual valves.

 

Only difference between disc and drum masters is the size of the reservoir, unless it has built in residual valves


Sent from my iPhone using H.A.M.B.

 

Much obliged, @RICH B

 

So I purchased the Cardone 101485. I thought it would work great, but the wishbone will interfere with the brake lines. So MORE questions...

- To use this master cylinder I would need 90 degree fittings coming out of it. Do they make them?
- Is there one (a different Cardone unit) with the same bore/stroke and same end where it bolts on? The bracket is already installed so need the same bolt pattern size.

I've seen some others Cardone ones mentioned in this thread... but how do I know if the bolts will be the same where it mounts?

Help me if you can!

Thanks
Vinnie

 

10-1373 might work for you; same 1" bore with porting on the opposite side.

 

Thanks Rich!

That's an American Motors according to Rock Auto. Would American Motors typically have the same mounting holes as a Ford Mustang? I think my original purchase was a 67 Ford Mustang.

 

And yes they make 90 deg fittings

 

Ok so I used a 1965 Mustang master cylinder as the fit was best. It's a single reservoir. Everything seemed to be going well bleeding the brakes and I believe all the air is out of the lines. BUT the pedal still goes all the way to the floor and never really got stiffer.

So do I need a residual valve? I did some searching and its seems I might need one... so questions:
1. Do I need it?
2. If so, 10lb?
3. Does it go in from brake lines, rear, or both?

Remember these are 46-48 drums all the way around, manual brakes.

Let me know.
Thanks!
Vinnie

 

Which Mustang cylinder did you get; '65 came in 7/8", 15/16", or 1"? 1" should work, although with a lower pedal to start with; the others not so much.
Should be a residual check in there; but who knows, these days.
Are your brakes adjusted good?

 

Brakes are all adjusted. It's a 1". CARQUEST MCA32900

https://shop.advanceautoparts.com/p/carquest-wearever-brake-master-cylinder-mca32900/10420740-P