Lets talk about Master-Cylinders

[Edbert]

I know next to nothing about the variances in these, I know I want a dual reservior, it was stock in my year anyhow but beyond that I do not know what options I even have.

My car came stock with power disc brakes up front and small drums on an 8" out back. I have a new replacement of that factory MC and a factory replacement power booster. Since I added the 12.2" discs out back (on a 9" now) I bought a proportioning valve but have not plumbed that yet. I recently added 13" Cobra front brakes and figure the stock master cylinder may not be a good choice anymore.

Opinions on using the stock cylinder?

What about the aftermarket prop-valve?

Should I even use the factory distribution block on the fenderwell very near the MC?

I built my motor for torque instead of HP and should have plenty of vacuum, what about using a late model booster? Any advantages or disadvantges? I am using a late model alternator, transmission and starter; but each of them had a significant benefit to a stock style part.

Fill me in on boosters and MCs please

 

[5.0ina66]

You can use a GVM 4x disc MC, SVO Mustang MC, Conti/Mk7 MC, or 94+ GT MC. You can use a late model booster, and I've seen a '90GT booster in a 67. AFAIK, you need a proper 4x disc dist block. I wouldn't use the stock MC, even though I know some people have after removing the residual valves. The 4x disc MCs are bigger for a reason. (Namely, discs take a greater volume of fluid)
HTH
--Kyle
PS: You can see a great comparison of all factory MCs on Ultrastang's site.

 

[Edbert]

Sounds like the SN95-GT ones would be cheapest and easiest to find at the counter, any reason not to use a SN95 booster? Are all of these things universally mounted, as in, the same bolt patterns?

I went to Steve's website and could not find the MC info, do you have a link?

 

[DarkBuddha]

Kyle's is a darn good response, and I agree pretty much across the board. I think the key point is that discs require more volume, while drums require more pressure, which means you want an MC that will move adequate volume and has adequate volume capacity. With that in minde, don't ignore bore diameter as part of the equation. Anyway, you might wanna call some of the big brake companies like Baer, Wilwood, SSBC, etc. for their opinions. Otherwise, I think Kyle's suggestion of the '94-up GT or Cobra MC might be an excellent choice since it had a similar setup to your current setup. Besides, newer MC look totally custom.

As for a booster option, unless you're going with a system like Hydroboost, the only benefit of a newer vacuum booster is their slightly smaller size (compared to a vintage booster). If that is enough incentive, then do check out Ultrastang's site to see his install of a Fox body booster into a vintage Mustang. If you're interested in something tricker, check out Hydroboost.

As for the stock distribution valve, it may not be necessary to use it unless it has the brake light switch in it (which I don't think it does). If you do use it, just verify all of it's components and check if it has any valves (residual or otherwise). I would recommend an aftermarket proportioning valve. This is an excellent tuning aid for any brake system. It is usually plumbed into the rear line to help control rear brake lock up (which is more likely because of the weight transfer of our frontend heavy cars).

Hope this helps...

 

[DarkBuddha]

I went to Steve's website and could not find the MC info, do you have a link?

http://www.ultrastang.com/Ultrainfo.asp?Page_ID=15

Booster install: http://www.ultrastang.com/Ultrainfo.asp?Page_ID=16

 

[Edbert]

As for a booster option, unless you're going with a system like Hydroboost, the only benefit of a newer vacuum booster is their slightly smaller size (compared to a vintage booster). If that is enough incentive, then do check out Ultrastang's site to see his install of a Fox body booster into a vintage Mustang. If you're interested in something tricker, check out Hydroboost.

I'm starting to think I'll keep my booster then, simply to avoid removing/welding/modifying my pedals. Then I can get a gigantic volume aftermarket MC, made out of aluminum with a plastic cover too.

As for the stock distribution valve, it may not be necessary to use it unless it has the brake light switch in it (which I don't think it does). If you do use it, just verify all of it's components and check if it has any valves (residual or otherwise). I would recommend an aftermarket proportioning valve.

The stock PDB distro-valve has a switch in the top of it for the brake warning light in case either reservior/curcuit of the brake system gets too high or too low on pressure. Is that the brake light you mean or are you refering to the brake light switch on the pedal?

I honestly do not know the internals of that distro-valve. I can see a residual valve being used in there but I can also see it just being a splitter. Two lines in three lines out. The prop-valve I have is from Wilwood (makers of my 12.2" rear discs), I'll definitely need to rebalance the car some with it. Optimal device would be to somehow combine the functions of my adjustable prop-valve with the OEM distro-valve into one unit. Maybe someone like Lokar makes something like that....hmmm.

 

[DarkBuddha]

The stock PDB distro-valve has a switch in the top of it for the brake warning light in case either reservior/curcuit of the brake system gets too high or too low on pressure. Is thet the brake light you mean or are you refering to the brake light switch on the pedal?

I knew about the warning light, but I believe there were distribution blocks in some vintage fords that actually had the brake light switch built-in. I just couldn't remember if that applied to early Mustangs. I know my '70 block only has the warning switch.

 

[5.0ina66]

I knew about the warning light, but I believe there were distribution blocks in some vintage fords that actually had the brake light switch built-in. I just couldn't remember if that applied to early Mustangs. I know my '70 block only has the warning switch.

I think the brakelight switch in the dist. block was a 64.5-early 65 thing, because I saw something to that effect mentioned when Ultrastang or someone had to rig up this funky little thing with a microswitch on the brakepedal in a 65 to get the brakelights to work after a front disc/MC/dist. block swap.
HTH
--Kyle

 

[NasaGT]

This is a most excellent thread - thanks for the good info in here guys!

 

[68converted]

My '68 valve has the brake light switch built in. I pulled a dist. block from a 84' 4cyl. mustang that was still filled with good brake fluid. It also has the brake light switch on it and is an exact fit with the original switch clip. I went with a '70's Maveric MC because I only have front disc brakes. I even kept the old push rod so the pedal height is the same. You can find plenty of MC's that will work with your original set up. I like the Maveric MC because the lines exit to the fender side... the room is needed with my conversion. To get the original pushrod out, put the MC in a vise and hold a solid bolt or screwdriver in the hole that the brake lever attaches to... a couple of solid wraps on it and it will pop out. Just use the "new" pushrod retainer ring to hold the "old" rod in the "new" MC. Just thought I would toss out another option for you... Good luck. You will really like the big brakes!

 

[Edbert]

Does anyone know why the 65 and 68 had the brake light switch in the distro block but 66 and 67 had them on the pedal?

I cannot use the hyrdoboost as I'm not running a power steering setup.

I have the factory PDB front distro-block and the stock MC. UltraStang used a MkVII distro block and MC, and a 92-LX booster. I have the manual distro-valve but fear the prospect of plumbing all that when the original ones already fit. How heavilly recommended is the "upgrade"?

 

[Edbert]

Well, here's an update and another question. The GIANT Wilwood MC will not fit on a 67/68 (probably 69/70 too) with the factory booster. I read on UltraStang's site that the 4cyl Mustang/Zephyr used the smaller boosters while the V8 and convertibles from the same years used the bigger booster (about the same size as my '67 booster).

UlraStang said his pedal efforts and stopping power were both inproved by using the smaller 4cyl booster, but he was coming from a manual setup so I'm thinking....DUH! Do you guys think I'll be dissapointed with the performance by using the smaller booster? I checked around and I can get an ARI unit for $74.99 with e $16.50 core charge, or a CARDONE for 64.99/26.00, or a Bendix for 78.48/20.00. I am leaning towards the Bendix since I have at least heard of them...LOL.

I guess for less than $100 it is worth trying but I already have one and don't want to have TWO power boosters I cannot use.

 

[cardude]

subscribing...

 

[bnickel]

Edbert, another option to look at is the distribution block from a late 70's-early 80's trans am with 4 wheel discs.

 

[68restoman]

You may also want to consider going to a tandem master cylinder like the JMC unit. It's more money but you wouldn't need a booster or a proportioning valve...

68Restoman

 

[Edbert]

You may also want to consider going to a tandem master cylinder like the JMC unit. It's more money but you wouldn't need a booster or a proportioning valve...

There's a couple of guys here that have these, they are looking at removing them due to the extreme pedal effort. Kind of dissapointing to hear too, there was a thread yesterday about the JMC hydraulic clutch being problematic too.

 

[Jimmys66]

I'm looking to do this same brake swap but my set up is all manual drum. I'd like to stay with non-power brakes.

Will the pedal pressure be too hard with non power 4 wheel disk?

 

[68restoman]

There's a couple of guys here that have these, they are looking at removing them due to the extreme pedal effort. Kind of dissapointing to hear too, there was a thread yesterday about the JMC hydraulic clutch being problematic too.

I'm surprised to hear that. There's several guys from my local club that run them, including some very fast 427 powered Daytona Coupes. I think maybe people have trouble with them because they don't size the cylinders properly or try to do things they aren't designed for like running drums in the back. Below is a picture of one of our club cars with the setup, it's a pretty serious race car as you can see.

68Restoman

 

[5.0ina66]

I got so interested in putting power 4 wheel discs on my manual trans. 66, that I did some more research, and measured some stuff I had, and got measurments of some other stuff.

A V6/V8 MustangII booster and a SVO/Mk7/Continental MC will work on your car, as will a 5.0 mustang booster, or the 2.3 booster that you mentioned (since yours is an auto).

I know the stock 67 power disc MC & booster are 14" long, combined length, and 14" is about all the room you have. The stock booster is 7" diameter

The mustangII booster is 5.5" long and 7" dia.

The 2.3 booster is 9" dia and 4.5 long, and I dunno the dimensions on the 5.0 booster

The SVO/Lincoln MC is a hair over 8" long, whereas disc/drum MCs are right at 7" long.
HTH
--kyle

 

[Cbarton]

Well, although I don't have a lot to compare it too, I LOVE the JMC setup in my mustang. The brakes ARE firm, but not overly so in my opinion......but then I never had it with the stock brakes so....take it for what it's worth.....

Chris Barton

There's a couple of guys here that have these, they are looking at removing them due to the extreme pedal effort. Kind of dissapointing to hear too, there was a thread yesterday about the JMC hydraulic clutch being problematic too.