I need a brake power booster.

CornerCarvin67

New Member
Dec 30, 2004
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Here's the skinny. I bought my car (67) with drum brakes front
and back. A couple years ago I put in the Baer disks front and
rear. I didn't use the dual master cylinder they gave me because
I already had a dual in there from the previous owner. I have no
clue if it was original or after market. I put in the kit and everything
works just fine. Well now I think I'd actually like to take advantage
of all that braking power by putting in a booster. Since I put in the
disks.... I pulled out the auto trans and put in a T5 with the Mustang
Steve cable clutch kit. It all works great. So... where can I purchase a
power booster to fit my application... no... I'm not digging in a bone
yard. It's ten degrees outside and you never know what you'll get
in a donor. The booster can come with a new dual master cylinder
or not... doesn't matter I guess. I just want to be sure that the
booster will fit MY application... ie: cable clutch, manual, disks, etc.

thanks for your time....
 
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CornerCarvin67 said:
The booster can come with a new dual master cylinder
or not... doesn't matter I guess. I just want to be sure that the
booster will fit MY application... ie: cable clutch, manual, disks, etc.

Any 9 inch booster should fit. You can get them from Master Power Brakes, SSBC, etc. If you have 4 disks, you would want a MC with a 1 1/8 inch bore. You also have to replace the pedal. You have to drill a hole in the bracket to relocate the mounting point and that is a major job. I just did a power disk conversion for my Wilwood 4 disk set up and if I could do it all over again, I would have got a JMC dual MC instead. I wish I knew then what I know now.
 
You can use a stock booster, but that requires a stock power brake pedal ($$$, and manual ones are worse!) Some other Ford boosters are bolt-in, with the manual pedal.

I've been considering the MII and 5.0 Mustang boosters for my 4xDisc/T5 swap, and I was told by a friend of mine that the 5.0 booster is a bolt in and you can use the manual brake pedal (they used an 87GT booster on his 68 project car with great success).

I'd use a Ford 4Xdisc MC, but be careful; the GT booster is ~7" long and the SVO MC is ~8", and you only have ~14" in between the shocktower and the engine bay, so that won't fly. IIRC, a Versailles 4xDisc MC is shorter, so maybe that's the ticket.

You could also use the 2.3 Fox booster and at 4.5" thick and 9" dia., it leaves LOTS of room for the MC. The MII MC is 7" dia and 5.5" long, so plenty of room as well.

Thinking about it, the 2.3 booster is probably your best choice as it's supposed to be a bolt-in for manual brake cars and leaves lots of room for the MC. The only downside to that booster is it covers up the clutch rod hole, but that's not an issue for you.
HTH
--kyle
 
Be sure to check with Steve, as his cable conversion doesn't leave much room to spare around the booster. I had to buy a smaller diameter booster to fit my application. I have a 66 which is a little smaller in engine bay, but I'd still check with Steve prior to buying any booster.
 
Here was Mustang Steve's reply....

I have a 67 power brake pedal (original ) and a new rebuilt Bendix booster that will bolt right on. This is the last one in stock and rebuilder says there are no more. It does not have the stamped steel plate that goes between the booster and firewall, though. Would have to either find an original or use one of my billet aluminum ones.
Pedal $100 Must have power brake pedal to get correct pedal ratio for power brakes.
Booster $250
Billet spacer $90
Template included
Shipping $15

So there it is... crap!! I have other things to buy before I drop 500 into my brake system. Can anyone add any positive or negative testimony to using the JMC master cylinder? Does is really work almost as good as a power booster set up? I need to know!!
 
I did the 5.0 Booster on My 69 Mustang Last year. Im running Granada Disc

Brakes in The front. I Found all my Info on the ultrastang website. I had

to do a little cutting and drilling on the firewall to make it fit. Instead of

Taking out the Manual Brake Pedal I Turned the Powerbooster Rod 180

Degrees and It attached to my pin on the the Brake pedal. I also swapped

out the Manual brake pedal switch for a power Brakes switch that went

right in. I could beleive how great the brakes worked after the conversion.

The pedal goes down 3/4 of inch before the brakes kick in. The best thing

was the booster cost me $12.00 on Ebay and It came with the master

cylinder that I sold back on Ebay for $7.00. I used a Granada Master

Cylinder. Hope this Helps you out.

Steve69
 
I beleive that the power brake switch takes less pressure to activate it.

It seems to activate the light better than the manual switch. I beleive

I Bought it at Napa for less than $10.
 
CornerCarvin67 said:
Yep... over my head. Guess I'll be looking to go a different route some how? Did you read my post in the other thread talking about the JMC master cylinder? Thoughts?

well, honestly, if Steve's tech is over your head, you don't need to be messing with your brake system to the extent you mention. Brakes are a 'safety of flight' item that HAVE to work right the first time, every time. Keep asking questions and understand what you are doing before you do something wrong brake-wise and injure yourself/someone else on the road. :nice:
 
Well maybe it's not so much over my head as I'm just probably too lazy to want to do it. After the last couple days of research and discussion.. I've gained a better understanding of the brake system. Point is... the power booster simply makes it easier to apply the braking pressure by usage of your foot. It doesn't enhance the amount of pressure the calipers create. I just wanted to be sure I was realizing the full potential of the fancy Baer kit I installed a couple years ago. If that means I have to use a little more of my 6'3", 260 pound arse to push harder.. so be it. I'm not racing two hour enduro events.... just autocrossing.

I was just in a conversation with a buddy about the size of the master cylinder valve. I think I see that they typically run 3/4 or 7/8. Do these different sizes greatly effect things? I understand that it increases or decreases the ratio of pressure between the MC and the calipers... but is that small diameter difference really noticable??

And no... the stuff that Steve has isn't really that bad... I used his cable conversion when putting in my T5 last spring. Like I said... just lazy and too busy with too many hobbies... not to mention kids... :)
 
basically you have it correct, power and manual brakes both get to the same point (lockup, eventually) by a slightly different route...the manual is more linear, more effort, and has better 'feel' (for some), the ramp is steeper for power (more leverage, less 'feel'). But the destination is the same. Most racers/trackers prefer manual b/c they can 'feel' the system work more, and can modulate it better...the additional effort is not a factor to them. But ultimately, if all is well mechanically, both systems will lock up the brakes at some point, at which time you no longer control the stopping point of the vehicle (now depends on your tires, friction, road surface, etc).

yes, the MC bore size makes a difference in pedal effort, and can in some cases make the difference in getting full pedal pressure to the calipers with reasonable effort.
 
CornerCarvin67 said:
So has anyone have opinions on the bore size as to what is better?


A poster here whom I generally consider to be an uninformed schmuck when it comes to tech matters actually gave the correct answer to you. Please see the first reply to your original question for the correct bore size you want with 4 wheel disk brakes.
 
Nice Jerry.... :)

Hey, is that 1-1/8 bore MC for if you have a power booster? Of if you just stayed with the manual set up? I've decided to not pursue the power booster idea. But I wouldn't mind optimizing my manual system. So I guess from what I've learned.. the only thing I can really do is get the best bore sized MC for what I have. Is there really a MC that works better than another? Why go with the pricey JMC unit if it won't perform than my current dual bowl MC? Looks don't really matter to me at the moment.

Hey... another question.... does anyone know if that factory distribution block mounted on the fender wall acts as a bit of a bottle neck on the system? Would it be more efficient to have a Tee there, for the front lines. And then the proportioning valve in the rear line.