Rear Disc Conversion (What Master Cylinder?)

ultrastang · May 15, 2007

Protowrxs said:
So I assume this is true on a 1969 Disc/Drum MC as well then?

Has anyone used an 86 SVO MC on a 1969 booster?

I have stock front 69 disc and SN95 rears going together using Ultrastang's brackets. I already have a variable porp valve installed but am not sure on exactly which MC I will need.

Good thread for sure.

-Stephen

I don't know the exact dimensions of the stock '67-'70 Mustang brake boosters, but I do know that they are VERY close in size to the '87-'93 Fox 5.0L brake boosters.

The photo below shows a '90 Mustang GT 5.0L brake booster in a '68 with an '84-'90 Mk VII 4-wheel disc MC mounted to the booster, (same thing as '84-'86 Mustang SVO MC), I had to radius the left front corner of the Mk VII MC's snout, but as you can see, it is mounted between the booster and the shock tower and the MC isn't touching the shock tower.

I don't know if this setup would work on the '65/'66 models, because of the shape of their shock towers, but the '67-'70 Mustangs share pretty much the same engine compartment/shock tower configuration.
http://img379.imageshack.us/img379/2716/foxboostermkviisn95mc00ey9.jpg

http://img266.imageshack.us/img266/513/mkviimc001hg5.jpg

Left front edge of Mk VII MC's "snout" radiused. http://img379.imageshack.us/img379/1258/mkviimc002sc7.jpg

http://www.ultrastang.com

Protowrxs · May 15, 2007

Wow.. It looks like on my 69 with a stock booster there is only 7 1/2" from the booster face to the tower. I'm not sure how I could get the extra length to work without notching the tower. Fun fun...

Looking for more options I guess.

-Stephen

gsxrken · May 15, 2007

Protowrxs said:
Wow.. It looks like on my 69 with a stock booster there is only 7 1/2" from the booster face to the tower. I'm not sure how I could get the extra length to work without notching the tower. Fun fun...

Looking for more options I guess.

-Stephen

Check this thread out:
http://forums.vintage-mustang.com/showtopic.php?tid/1459960/

Protowrxs · May 15, 2007

gsxrken said:
Check this thread out:
http://forums.vintage-mustang.com/showtopic.php?tid/1459960/

Thanks... looks like something to give a try.

BTW - I PM'd you at 1969Stang.com.

-Stephen

ultrastang · May 15, 2007

Protowrxs said:
Wow.. It looks like on my 69 with a stock booster there is only 7 1/2" from the booster face to the tower. I'm not sure how I could get the extra length to work without notching the tower. Fun fun...

Looking for more options I guess.

-Stephen

I have customer, in Washington state, who has the same SN-95 V6/GT rear disc bracket setup that you got from me.

He was asking me about MCs when he was trying to put the parts together for this swap, and said that his '68 has the factory '68 power brake booster. I told him that the '94-'04 V6 4-wheel disc MC should work, since the SN-95 V6 MC is 7-3/8" long. He got the V6 MC and it did fit in his '68 on the stock booster. Picture of Ron68's MC setup; http://img261.imageshack.us/img261/725/ron68sn95reardiscs5dd1.jpg

The ports are metric and they exit on the passenger's side of the MC, but it did fit his stock booster in his '68 with a 351W.

This is a photo I took 3 years ago when I used this same SN-95 V6 MC on the "guinea pig" '65 fastback I was trying to figure this rear disc swap out on; http://img480.imageshack.us/img480/5433/65050jh3.jpg

http://img514.imageshack.us/img514/9887/kieths65053vw9.jpg

Obviously, the 2.3L Fox booster I used in the '65 is much "flatter" than your stock '69 booster, but this just gives you an idea that the MC works.

http://www.ultrastang.com

Protowrxs · May 15, 2007

ultrastang said:
I have customer, in Washington state, who has the same SN-95 V6/GT rear disc bracket setup that you got from me.

He was asking me about MCs when he was trying to put the parts together for this swap, and said that his '68 has the factory '68 power brake booster. I told him that the '94-'04 V6 4-wheel disc MC should work, since the SN-95 V6 MC is 7-3/8" long. He got the V6 MC and it did fit in his '68 on the stock booster.

Excellent - I think I'll go that way. Actually I have no issues with the ports being on the other side, it will makes things easier to plumb for the porportioning valve and line lock in the long run.

Thanks guys!
-Stephen

Jimmys66 · May 16, 2007

torino420 said:
Yea it is 15/16" from what i've read, i dont recall are you using a booster or not?
I'd love to see a pic of this MC mounted directly to the firewall.

Other option im looking at is a 88 daytona mc that is a 7/8" bore but would prefer a ford part but just not finding what i need at the moment.

No booster. Manual Brakes. I still can't believe this combo was for a power brake car. It works great without a booster. Same pedal pressure as my manual drums.

torino420 · May 16, 2007

Anyway you can get a pic? I'll be glad to host it. I really want to see how this thing looks directly on the firewall.

edgars23 · May 16, 2007

This is a great read. Too bad I don't know too much about braking systems. I am learning everything on the go and this is a great thread for me.
I will eventually want to go to the SN95 brakes on my 67 coupe, it currently is an all drum car. What would the recommendations be for my situation? If anyone in my situation wanted to upgrade to complete sn95 brakes, what booster/mc combo should be used? any advantage to using the 2.3l vs. a 5.0l setup (booster that is)?
Does anyone know if there is a definitive write up on this subject? Showing step by step progress?
Not trying to hijack a thread, just figured it would be some great clarification for everyone that would like to try this mod.
-Edgar

Rusty67 · May 17, 2007

Why does everyone want to put in the newer style MCs ? I think they look terrible, but that is just personal preference. Is it a space constraint issue ?

ultrastang · May 17, 2007

Rusty67 said:
Why does everyone want to put in the newer style MCs ? I think they look terrible, but that is just personal preference. Is it a space constraint issue ?

There are a number of advantages to the "modern" MCs vs. the older MCs.

A '67-'70 Stock disc/drum power brake MC weighs 6 lbs. An SN-95 MC weighs~1½ lbs.

The modern MC doesn't rust. It's abou the same length as the stock cast iron MCs, and you don't have to take the top off to see how much brake fluid inside.

Taking the top off lets air and dirt get into the brake system --neither of which is a good thing to happen.

Rusty67 · May 17, 2007

The SVO MC is fairly light altho I know it has a huge bore size which is a little large for some applications. With a power booster I don't see it being too large for most large brake systems. I just hate the way the plastic tanks look.

gsxrken · May 17, 2007

Plastic tank looks fine right next to my plastic clutch reservoir 
Light is right.
Doesn’t rust.
Can eyeball the fluid level and color
But first and foremost: Fits between the 1969 booster and shock tower, unlike the 8-1/4 long SVO unit

Rusty67 · May 17, 2007

gsxrken said:
Plastic tank looks fine right next to my plastic clutch reservoir 
Light is right.
Doesn’t rust.
Can eyeball the fluid level and color
But first and foremost: Fits between the 1969 booster and shock tower, unlike the 8-1/4 long SVO unit

I understand looks are personal preference. The SVO MC is quite light as well as it is all aluminum. You should update to a more modern booster anyways. They work better, are smaller and have a better pedal feel.

Jimmys66 · May 17, 2007

torino420 said:
Anyway you can get a pic? I'll be glad to host it. I really want to see how this thing looks directly on the firewall.

Certainly. I'm a little picture posting stupid and don't have a host site. PM me your e-mail and I'll send you a couple to post.

ultrastang · May 17, 2007

Rusty67 said:
I understand looks are personal preference. The SVO MC is quite light as well as it is all aluminum. You should update to a more modern booster anyways. They work better, are smaller and have a better pedal feel.

The SVO/Mk VII 4-wheel discs aluminum MC is lighter than the conventional cast iron dual reservoir MCs, but the down side to the SVO/Mk VII MC is it's nearly 5/8" longer than most other MCs. This makes a big difference when you have a brake booster (depending on type), in that you MAY not have a enough room out in front of the booster for the MC to clear the back of the shock tower.

torino420 · May 18, 2007

Jimmys66 said:
Certainly. I'm a little picture posting stupid and don't have a host site. PM me your e-mail and I'll send you a couple to post.

PM Sent, thanks.

gsxrken · May 18, 2007

Rusty67 said:
I understand looks are personal preference. The SVO MC is quite light as well as it is all aluminum. You should update to a more modern booster anyways. They work better, are smaller and have a better pedal feel.

Two things- the SVO unit I had was iron with the iron bowls and steel lid, so they may not all be aluminum.

The other thing is that converting to a modern booster is a heavyweight solution when one can just get a shorter M/C like I did and the problem is solved. New ones are expensive, they have a different bolt pattern and pushrod deal, and the job is a nasty one. But on top of that, I also don’t recall ever hearing that newer ones work or feel any better. In my case, I have no issues with my pedal at all (although I also run a vacuum can to store extra vacuum).

My stock PDBs are excellent for the street and autocross loops; I only went with 4-wheel Wilwoods for 2 open track dates a year. Kind of silly when I read it in print- oh well.

Rusty67 · May 18, 2007

One of the main reasons I've heard everyone upgrading to the later model boosters is because of that "modern pedal feel". Maybe not all SVO MCs are aluminum, thats good to know.

The 2.3L booster swap isn't straight forward but there are other swaps that supposedly "bolt right in" for the most part (meaning no major modification neccisary).

bnickel · May 18, 2007

i found this master cylinder on the scott drake site that is for 4 wheel discs and looks just like a stock master and even has the lines on the correct side.

http://www.scottdrake.net/prod_deta...+::+Disc+Brakes+::+Disc+Brake+Master+Cylinder

Rear Disc Conversion (What Master Cylinder?)

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