Need help finding master cylinder brake line reducer

Need help finding master cylinder brake line reducer

I bought a new master cylinder from NAPA and new break lines a while back. The thread in the maser cylinder is a 3/8-24 thread while the line I have that goes from the proportioning value to master cylinder is 1/2-20 thread. Has anyone ran into this. I can find reducers that go from 1/2 female to 7/16 male but not 1/2 male to 3/8.

I'm also a little concern about the master cylinder being right.

Any help would be appreciated.

thanks

I went out and measured mine, power disc/drum, the front fitting is 1/2 and the rear is 3/8.

I believe the drum/drum master cylinder is 3/8 and 3/8. The bowls for the drum/drum are also the same size.

ran into the same problem got my reducer at autozone not sure the size I just kinda sized it up in my head

So apparently Cardone mixed up the boxes and sent the wrong master cylinder but no longer make the correct part. I also have the problem that the 1973 is different from the 1971-72 master cylinders. still trying to figure it out.

sdstang

I believe the difference is the size of the bore. The early Power disc with Drum brakes had the 1 inch M/C Bore. The after, " 7/1/72" M/C has the 15/16 inch bore. A larger-diameter master cylinder will displace more fluid volume than a smaller-diameter unit, but will create less line pressure. The result is a harder pedal requiring more braking effort.



Source: Ford Master Parts, Copyright May 1975

Here is the early model Master Cylinder C8ZZ--2140-B

http://www.macsautoparts.com/ford_mustang/ford-mustang-master-cylinder-new-dual-chamber-before-7-2-1972-for-power-disc-brakes.html

mustang7173

sdstang

I believe the difference is the size of the bore. The early Power disc with Drum brakes had the 1 inch M/C Bore. The after, " 7/1/72" M/C has the 15/16 inch bore. A larger-diameter master cylinder will displace more fluid volume than a smaller-diameter unit, but will create less line pressure. The result is a harder pedal requiring more braking effort.

Source: Ford Master Parts, Copyright May 1975

Here is the early model Master Cylinder C8ZZ--2140-B

http://www.macsautoparts.com/ford_mustang/ford-mustang-master-cylinder-new-dual-chamber-before-7-2-1972-for-power-disc-brakes.html

mustang7173

Click to expand...

Thanks for clearing this up. I was hung up on the 15/16 vs. 1" bore.

-Jim

sdstang, I went through the same thing for my '73 with power brakes, disk up front, drums in back. 3 or 4 different parts stores told me they could get the right master cylinder with no problem. They all ordered it. They all gave me different master cylinders. Some needed an adapter/reducer on the front, some on the back, they were just all over the board. That was the case even though all of them took the time to identify it as power brakes, disk fronts, drum backs, 1973, etc.... Finally, I took the closest one and used an adapter that connects the brake line to the master cylinder. It was as close as I could get.

I think you hit the nail on the head. Cardone (and I assume other rebuilders who market the rebuilt master cylinders) just do not take the time to distinguish the subtle differences when they get the cores in. I was warned of this and was told if you keep sending it back and keep ordering it again you will eventually get one that was the right core to begin with and you will not need the adapter. I gave up after 4 tries. I still have my original, but I'm using a rebuilt one with one adapter as described above.

I'm surprised that NAPA didn't have the adapters.

Locally, they're the only ones that had the proper ones for my '98 Expedition brake lines (no Autozone, Carquest or Advance). Had 'em behind the counter in an assortment box, had to ask for them.

Same problem I have now.

My original MC was leaking a bit, primary (front brake) 7/16 and secondary 1/2. I ordered one, Dorman M36445 (made in China), primary is 7/16 and secondary 3/8. I try to find locally a 1/2 female by 3/8 male, but here no chance.

Anyway, My front brakes are rebuilt, new seals, clean pistons, beautifull pair of second hands calipers, and new kit (thanks Eddy) with a leaking MC.



3/8 secondary, 7/16 primary







1/2 secondary, 7/16 primary

Any shop where I can find an adaptor?

Thanks for help.

Why not make up a new section of line to go from the proportioning block to the master cylinder with the right fittings instead of using adapters?

I didn't think about that, yet.

Why not. But It's more easy to add a fitting I guess? Or mabe can be more chance for leaks?

We got one from NAPA last year and it has the right size fittings and was in stock

I work at a napa and we have a large selection of brake adapter fittings and what i came up with is 2 adapters. One going for 3/16 inverted seat (3/8 - 24) to 1/4 inverted seat (7/16 - 24) which is napa part # 7828 and the other goes from 1/4 to 5/16 inverted seat (1/2 - 20) and the part number for that is a Napa # 7917. Please let me know if you need some other assistance i can pull out a book during some down time, hope that helps!

Oh yesxplain. that helps, just I'm confused about male, female, inverted, I know what I need but not easy to explain.

For example, on the Dorman 36445 I have in stock and would like to use, there are 2 red caps (protector), written on them 3/8 and 7/16.

Those size corresponding with the tool I need to screw them, I guess, I'm lost with that.

My english problem to understand details + english unit, that's not help me.

M2153 is my NAPA part number that interchanges from that Dorman number which has 3/8 - 24 Female thread as one inlet and 7/16 - 24 female thread on the other which translate to 3/16 and 1/4 inverted flair fittings respectively. the adapters i listed one goes from 3/16 to 1/4 the other goes from 1/4 to 5/16 which is 1/2 - 20 threads and those are bell reducer fittings meaning the go from a smaller male tread size to a larger female thread size. does that answer your questions by chance if not please throw some more at me ill see what i can do!

I need to read again your post, but anyway it's more clear

" 3/8 - 24 Female thread as one inlet and 7/16 - 24 female thread on the other ".

So, My original MC inlet are: 1/2 and 7/16.

The new MC is: 3/8 and 7/16.

What I need is an adaptor from 1/2 to 3/8.

Means, I need 3/8 by 1/2 (3/8 thread and 1/2 inlet), is that ok?

And why

1/2 is 5/16?

3/16 is 3/8?

I use to work with psi, barrels, inch etc... but for fittings, it's another story

Another question:

Which one is the primary and the secondary? I know the bigger bowl is for the front brakes.

The one I should buy:

http://www.raybestosbrakes.com/magnoliaPublic/raybestos/us/en/home/catalog/product.html?partNumber=MC36398

Brake tubing is measured by the diameter of the tubing itself. so a 3/16" brake line would be 3/16" on the outside dimension of the tubing. The nut that slides over the tubing would need to have threads larger than the outside dimension of the tubing because the tubing runs through the nut. So the "thread size" will be larger because it is the dimension of the nut that actually threads into the brake component (Master cylinder, wheel cylinder, caliper, etc.) The standard threads to tubing size is as follows

Tubing | Thread Size

1/8................5/16 - 28

3/16...............3/8 - 24

1/4.................7/16 - 24

5/16................1/2 - 20

3/8..................5/8 - 18

7/16................11/16 - 18

1/2..................3/4 - 18

5/8...................7/8 - 18

3/4...................1 1/16 - 16

7/8...................1 3/16 - 16

1......................1 5/16 - 16

So you needing to go from 3/8" to 1/2" threads the only way Napa can do it is with two adapters our Weatherhead supplier doesn't make a one piece connector. the two you would have to use are part numbers 7828 and 7917. I'm not saying its not made all i can say is that napa can only do it in 2 pieces

Tomorrow I will print out your thread size chart and keep it in my garage on the wall (and understand it).

Maybe this one is ok?

http://www.autoparts2020.com/rsdev/part_detail.jsp?PART_HDR_ID=1223270

Glad i can help. that one will work great by the way


scratch that that one wont work i just looked at it again