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View Full Version : power brake booster size (enough??)


OX1
12-18-2016, 07:27 AM
My parts 60 has a booster/MC that looks very close to this.

http://www.squarebirds.org/vbulletin/attachment.php?attachmentid=13376&stc=1&d=1480488692

My plan is front disk (which are not granada, but look very close to that setup, maybe later 70's T-bird??) and stock rear drum.

It appears to me this is a pretty small booster. I did get to drive my parts car on/off trailer and up and down driveway.
It does have 4 wheel disk and brakes felt great, but that was
at very low speeds.

Wondering what the largest booster someone has fit? Not from a kit, I don't care how much fabrication it will require.

I have an extra new NOS dual diaphram from a 93 F350 (may be overkill, but hate to waste time on smaller booster
that will not be adequate). It is huge, but works pretty well on my 79 bronco that weighs 6000+ lbs and has 43" tires on super heavy steel beadlock wheels.

jopizz
12-18-2016, 11:03 AM
That appears to be a standard 8" booster which is what you need for disc brakes. Anything larger isn't going to give you any better performance.

John

simplyconnected
12-18-2016, 02:21 PM
That picture is Marcelo's car, using a two-stage 8" booster. The two-stage boosters are easy to spot because they have that 'step' in them. I believe this is the largest booster you can fit. It is the same diameter as the OEM 10" (single stage) but a bit longer.

Believe me, if a two-stage 10" would fit I would recommend that over the 8". Here's the deal... We rarely ever do panic stops. We normally give just the right pedal pressure to stop properly. Too little braking will cause a collision and too much can get you hit from the rear (and aggravate your passengers). So we size the booster to deliver the maximum boost needed, up to and including locking up the brakes in a panic stop.

In my experience, the two-stage 8" does get you there. I would NOT recommend the two-stage 7". Yes, it works but not enough for me, in my humble opinion. Some of our members are happy using the OEM 10" on disk brakes but that (in my opinion) offers poor performance. The original drum brakes Squarebirds were borne with are downright dangerous, even with an original booster. I see 'dealer installed' trailer hitches on Squarebirds. I'm sorry but without disk brakes, that makes my skin crawl.

Let me say it this way... After experiencing OEM, then retrofitting to disk, the difference in performance is so profound I cannot say anything good about original brakes. - Dave

OX1
12-19-2016, 10:25 AM
OK, I looked at the parts car again and it is exactly that booster shown in the pic.
If that is good enough, I will use it. (just for kicks though, I am
going to break out that booster and see if it even fits under hood,
which I suspect it won't).

I will add though that every car/truck I have converted to HB, has been
a phenomenal improvement. Part of that was weight of vehicles and/or
oversize tires. The other half is I am very light and probably just don't push
as hard as many others. :eek:

Appears that MC is a 4 wheel disk GM (corvette??) master.
Any of the 70's car or truck FORD masters fit up to that booster
(again, even if fab work required)?

Also, does that booster have an adjustment rod internally?

Finally, do we know what that booster is out of, or is it
made just for some kit?

simplyconnected
12-19-2016, 12:41 PM
The booster is a 'universal' two-stage 8" that sells for ~$80 at piratejack.net (MBM #8531). (http://piratejack.net/universal-8-dual-diaphragm-booster/) Ford or GM style master cylinders fit this booster.

The M/C is a "MC1322H - GM Universal Cast Iron Master Cylinder (http://piratejack.net/gm-universal-cast-iron-master-cylinder-3-8-ports/) w/four-3/8" IFF ports and 1" bore" that sells for $55 at piratejack.net.

The combination proportioning valve, (PV2 GM-style # 25509419 Replacement Disc Drum Combination Valve (http://piratejack.net/gm-disc-drum-proportioning-valve-brass/)) sells for $59. The electrical 'idiot light wire' costs another five bucks.

Yes, boosters have adjustment rods on the input end (3/8" rod w/jam nut) AND the output end (metric screw w/jam nut)because not all master cylinders are machined exactly the same.
All these parts total ~$200. Let's talk about your firewall bracket. Have you got one? And to round out this installation you will need brake line and IFF nuts (7/16" and 3/8") all for 3/16" brake line). If you use your OEM brake light switch, you need a tee (3/8"-IFF x 1/8"-NPT x 3/8"-IFF). There are a few more incidentals, depending on what you already have. Wheel hoses and the rear end hose (three in all) must be changed as well.

We'll talk further about what you're missing. In the mean time, let's see a picture of your booster and your master. - Dave

OX1
12-19-2016, 08:00 PM
This is the setup I have

http://luxjo.supermotors.net/60%20T-BIRD%20PARTS/ORIGINAL/BRAKE%20BOOSTER.jpg

Thanks for all that info on the parts. Will probably
use this proportioning valve, since I am very familiar
with it on many of my other fords.

http://piratejack.net/1960-70s-ford-proportioning-valve/

Not sure on master, pretty sure my 78/79 broncos all
had 1" MC stock. Probably have one of them kicking
around new or near new.

http://www.partsgeek.com/gbproducts/MC/4953-07019993.html?utm_content=MC&utm_term=1978-1986+Ford+Bronco+Brake+Master+Cylinder+Dorman+78-86+Ford+Brake+Master+Cylinder+1985&utm_source=google&utm_medium=ff&utm_campaign=PartsGeek+Google+Base&gclid=CO33iqnIgdECFdaIswodupIIZQ&ad=47362750812
MC

Only thing left to find out is if that setup will fit with 430.

OX1
12-20-2016, 10:50 AM
Just for kicks, I plopped F350 booster under the hood to see
if it would fit. It appears show stopper, for almost any
booster, is the shift arm on lower end of steering col.
sticking almost straight up in park.

This particular booster has a mounting surface that
angles booster heavily upward, which could help if that
shift arm was re-configured sticking out at a lower angle
(which could make the geometry change enough the
actual trans shift pattern, no longer aligns with
indicator).

Anyway, this is is dual diaphragm, 10" dia by 7" thickness
and accepts the ford 70, early 80's MC's. I doubt I'll use it,
as the one I have from the kit appears to fit, seems to work
well enough for most, and is relatively cheap to replace.

Pics just for fun. EDIT: (changed pics to links, since I forgot this board does not allow bigger pictures)

http://luxjo.supermotors.net/59%20T-BIRD/60%20DISK%20BRAKE%20CONVERSION/F350%20BOOSTER/20161219_201025.jpg
http://luxjo.supermotors.net/59%20T-BIRD/60%20DISK%20BRAKE%20CONVERSION/F350%20BOOSTER/20161219_201058.jpg
http://luxjo.supermotors.net/59%20T-BIRD/60%20DISK%20BRAKE%20CONVERSION/F350%20BOOSTER/20161219_201128.jpg
http://luxjo.supermotors.net/59%20T-BIRD/60%20DISK%20BRAKE%20CONVERSION/F350%20BOOSTER/20161219_201256.jpg
http://luxjo.supermotors.net/59%20T-BIRD/60%20DISK%20BRAKE%20CONVERSION/F350%20BOOSTER/20161219_201416.jpg

simplyconnected
12-20-2016, 01:47 PM
Henry, we have been here before. Some of our power brake retrofit threads are so long it would take you a whole day to read through them all. After all is said, many of our members have successfully retrofit their Squarebirds with power disk brakes that work beautifully.

I started this quest because at the time there were NO kits available for Squarebirds. I thought it peculiar that every other car seemed to be covered but NOT Squarebirds. With the help of other members, we determined the SB firewall mounting for the manual brake master was too low (as you found out) for a booster.

The solution is to raise the bracket five inches. That in itself brings a 10" booster center to the height of a manual master. The next problem becomes, if we raise the booster then the brake pedal rod will also be five inches too low. The answer to that is to use a firewall bracket with a link or a lever. The brake pedal rod operates the center of the link and the top of the link operates the booster's input rod. Now we need room to operate the link.

Howard Prout has a '58 with A/C and a 430 MEL. He engineered a firewall bracket that raises the booster five inches and sets it out from the firewall another 5". He made two and had them chrome plated, one for his car and one that Ray Clark is currently using.

Since then, one supplier offers a kit with a proper firewall bracket, nearly identical to Howard's design. ABS only sells the bracket WITH a booster and master as a combination. It is ABS kit #9787. If you don't have a 1960 with a firewall booster you are limited to two choices; either buy the ABS kit or make your own bracket (like Howard did). Simply tilting the booster will not work because a dual diaphragm 8" booster is long but with a proper firewall bracket, it clears the snorkel on a 430 intake and the A/C plenum.

BTW, the booster in your recent photo's is NOT a dual diaphragm and it is different from two posts ago. - Dave

OX1
12-23-2016, 08:23 AM
I removed all my disk brake kit parts yesterday and
the brake pedal from the 60 parts car. I looked
through 5 or 6 of the largest disk brake threads,
you are right, lots of good info/pics in there.

First thing I noticed was the brake pedal had a
mechanism that appears to have been used with the
59 internal booster. I guess ford just left it on for
one more year since it doesn't hurt anything?

The next thing I looked at was pedal ratios. The
pedal is 13.5/2.25 or 6:1. The fulcrum bracket is
3.125/1.5, or 2.1:1. So the overall ratio is 6/2.1 or
2.86:1. I thought typical power disk/drum brake
setups where in the 3.5-4:1 range, no?

The bracket I have, which appears to have come with
the kit, only raises the booster up about 2 inches, so not
sure if that will be enough height (it fit in my parts 60,
but that has an AOD and floor shifter). The booster
size is 8", stepped down to 7" in the front.

I'm considering this combo, which is a dual 9-1/4 booster
and 1-1/16 master. I've always been partial to larger
boosters or hydroboost, and this may be the largest that
will fit. Also gets the the "ford appearing" MC that is at
least within a decade of SB's.

https://www.amazon.com/Cardone-50-3311-Remanufactured-Booster-Cylinder/dp/B000C4957S

BTW, that F350 booster is dual diaphram. Ford started
using dual diaphram on all half ton and up trucks in 1980.
Here is pic of a 79, 84, and 93 ford truck boosters.

http://luxjo.supermotors.net/GREEN_DILYSI/93%20F350%20BOOSTER/93F350_85F150_79_boosters.jpg


Henry, we have been here before. Some of our power brake retrofit threads are so long it would take you a whole day to read through them all. After all is said, many of our members have successfully retrofit their Squarebirds with power disk brakes that work beautifully.

I started this quest because at the time there were NO kits available for Squarebirds. I thought it peculiar that every other car seemed to be covered but NOT Squarebirds. With the help of other members, we determined the SB firewall mounting for the manual brake master was too low (as you found out) for a booster.

The solution is to raise the bracket five inches. That in itself brings a 10" booster center to the height of a manual master. The next problem becomes, if we raise the booster then the brake pedal rod will also be five inches too low. The answer to that is to use a firewall bracket with a link or a lever. The brake pedal rod operates the center of the link and the top of the link operates the booster's input rod. Now we need room to operate the link.

Howard Prout has a '58 with A/C and a 430 MEL. He engineered a firewall bracket that raises the booster five inches and sets it out from the firewall another 5". He made two and had them chrome plated, one for his car and one that Ray Clark is currently using.

Since then, one supplier offers a kit with a proper firewall bracket, nearly identical to Howard's design. ABS only sells the bracket WITH a booster and master as a combination. It is ABS kit #9787. If you don't have a 1960 with a firewall booster you are limited to two choices; either buy the ABS kit or make your own bracket (like Howard did). Simply tilting the booster will not work because a dual diaphragm 8" booster is long but with a proper firewall bracket, it clears the snorkel on a 430 intake and the A/C plenum.

BTW, the booster in your recent photo's is NOT a dual diaphragm and it is different from two posts ago. - Dave