Power Brakes on a 66'?
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ultrastang
Founding Member
I've used the Fox 2.3L booster in a '65 and '66 Mustang, and a Fox 5.0L version in a '68.
The 5.0L version in a '67-up Mustang will work with a hydraulic clutch MC, but won't work with a hyd. clutch MC in a '65/'66 body. There just isn't enough room beside the booster for the hyd. clutch MC to mount in the stock hole location on the firewall in a '65/'66.
In the '65/'66 body, no matter which Fox booster style you used (9" diameter 2.3L or 7" diameter 5.0L), you would have to use a cable clutch if you have a manual transmission.
Fox 2.3L brake booster in a '65 Mustang:
http://www.ultrastang.com/Images/Scanned/June2002/01.jpg
http://www.ultrastang.com/Ultrainfo.asp?Page_ID=16
mrmustangman357
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- Feb 11, 2007
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Ultrastang, how does the 2.3L booster's power compare to a factory/aftermarket 7: booster? Would it have enough power for disc/disc? or is there a later model mustang booster that can fit and give good power? I am going to a cable clutch so I'm not worried about linkage fitment too much, just packaging issues and booster performance. My SSBC 7" isn't going to cut it
ultrastang
Founding Member
Ultrastang, how does the 2.3L booster's power compare to a factory/aftermarket 7: booster? Would it have enough power for disc/disc? or is there a later model mustang booster that can fit and give good power? I am going to a cable clutch so I'm not worried about linkage fitment too much, just packaging issues and booster performance. My SSBC 7" isn't going to cut it
The Mustang pictured in the following links had Granada front discs and Mk VII discs on the rear, with a Fox Mustang 2.3L booster and a Mk VII/SVO MC:
1. http://www.ultrastang.com/Images/Scanned/Steven/01.jpg
2. http://www.ultrastang.com/Images/Scanned/June2002/01.jpg
3. This was the first Mustang outfitted with the Mk VII rear disc conversion brackets I developed:
http://www.ultrastang.com/Images/Scanned/April2002/36-s.jpg
Both styles of Fox boosters work very well, and in most cases, much better than aftermarket ones.
http://www.ultrastang.com/Images/Scanned/Jan2003/002.jpg
The 9" diameter x 4¼" thick ("2.3L") booster was used in ALL Mustangs (4-cylinder and 8-cylinder) from 1979-1986. In 1987, a change was made to the 5.0L Mustangs and 2.3L convertibles. The boosters in those models went to the smaller 7" diameter x 6½" thick ("5.0L") boosters, while the 2.3L coupes and hatchbacks still had the earlier style 9" diameter ("2.3L") booster.
The 2.3L-style booster and Mk VII/SVO MCs were used in the first Mustangs to come with 4-wheel disc brakes --the '84-'86 Mustang SVOs, so this combination does work very well.
Some more Fox booster info from my website:
http://www.ultrastang.com/Ultrainfo.asp?Page_ID=16
ultrastang
Founding Member
Yep. That's about the size of it. If you had a '67-up Mustang, the stock '67-'70 booster or the 5.0L Fox booster would work with a hydraulic clutch MC, but with a '65/'66 body, you would have to use the cable. The cable should clear the shorties.
mrmustangman357
Member
- Feb 11, 2007
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What about using a cobra booster? http://cgi.ebay.com/ebaymotors/1993...ryZ33566QQrdZ1QQssPageNameZWD1VQQcmdZViewItem
I heard a lot of road racers like to use these for increased stopping power. has this ever been tried on an early car? Ultrastang, are you saying the 2.3L booster is a good choice for 4 wheel disc 65/66 cars, especially over the 5.0L unit? are any pedal mods required for the early cars? I saw your website for 67-up but can't find where the 65-66 needs modification (if any)
I heard a lot of road racers like to use these for increased stopping power. has this ever been tried on an early car? Ultrastang, are you saying the 2.3L booster is a good choice for 4 wheel disc 65/66 cars, especially over the 5.0L unit? are any pedal mods required for the early cars? I saw your website for 67-up but can't find where the 65-66 needs modification (if any)
ultrastang
Founding Member
I've never attempted a Cobra booster in an early body. It's a good bit bigger than the Fox 5.0L booster:
'93-'95 Cobra booster on left, Fox 5.0L/ (and 2.3L convertible) booster on right:
http://img523.imageshack.us/img523/703/cobravs50lbrakeboosterao9.png
The '93 (Fox) Cobra R was the first Mustang to use this booster (as well as the 13" Cobra 5-lug front rotors and 11.65" Cobra 5-lug rear rotors before they became standard-issue in the SN95 Cobras). The Fox body doesn't have a problem with clearance to the strut tower in regards to MCs, but the Fox bodies had to have a dent knocked into the strut tower to clear the larger Cobra vacuum boosters.
With the early bodies, the problem is with the shock tower in relation to the MC. The booster and MC, combined, (on a '67-'70), has to have a combined length kept to within ~14½" overall to clear the shock tower. --'65/'66 Mustangs are near the same --maybe a little less due to the larger bulge of the lower portion of the shock tower compared to '67-up.
The 2.3L and 5.0L booster work about equally as well. The 5.0L booster is smaller in diameter, but is thicker than the 2.3L version. The 5.0L booster (in a '67-up at least), gives more room around it to install a hydraulic clutch MC, or to use the stock mechanical linkages (or even a cable clutch), you have to take the length of MC into consideration to clear the shock tower if using the (thicker)5.0L booster.
A 2.3L booster will not pose a problem with any MC, so long as the flange of the MC will bolt to the mounting studs of the booster.
Typical dual bowl Ford MC lengths are ~7½" long. This will fit in a '65-'70 Mustang with either style (2.3L or 5.0L) booster with no problems. A Mk VII/SVO MC, on the other hand, is ~8-1/8" long. This is too long to use on a 5.0L booster in a '65/'66, but I did get this combination to fit in my '68:
http://img503.imageshack.us/img503/5806/foxboostermkviisn95mc00cd5.jpg
I had to radius the left front edge of the protrusion on the tip of the Mk VII MC, and it's a close fit, but does not touch the back of the shock tower.
On a '65/'66 pedal, you would have to move the brake pedal pin downward ~ 1¼" and back 3/8" from the front edge of the pedal's upright to line up with the input rod of the 2.3L or 5.0L brake booster.
It's best to fabricate a reinforcement plate to weld to the front of the '65/'66's pedal support to add strength to the firewall to reduce firewall flex when the brake pedal is being applied. '67-'70 models have the advantage of an extra panel layer in this area for strength, and a plate is not as critical, but this is what the plate looks like that I made for my '68's pedal support --with the Fox booster's stud pattern drilled into it (2.3L and 5.0L booster stud pattern is the same) :
Reinforcement plate for '67/'68 Mustang: http://img513.imageshack.us/img513/2977/foxbrakeboostertemplateat1.jpg
Face of '67/'68 pedal support (unmodified on left, modified on right: http://www.ultrastang.com/Images/Scanned/Sept2002/12.jpg
Plate welded to face of pedal support:
http://img503.imageshack.us/img503/2629/68pedalsuppoert002fw6.jpg
Pedal support painted:
http://img513.imageshack.us/img513/6913/68pedalsuppoert003wi0.jpg
A plate for a '65/'66 would not look like the one I made for my '68's pedal support, but you get the general idea.
There aren't many choices for boosters that can be used with dual-bowl MCs on '65/'66 models that work as effectively as the Fox boosters. In the case of the '67-up Mustangs, a stock booster is obviously the easiest to install over the Fox booster, since they require no modifications to the firewall/pedal support, but at the time I did this conversion on my '68, I didn't have a stock '68 brake booster, but I did have a Fox 5.0L booster lying around.
ultrastang
Founding Member
On the theme of 2.3L boosters in a '65/'66 body...
This is an installation I did on a friend's '65 fastback back in '04. It features a 2.3L Fox brake booster and an SN95 V6 4-wheel disc MC:
1. http://img116.imageshack.us/img116/134/65053dh3.jpg
2. http://img116.imageshack.us/img116/6596/65054go8.jpg
The reason for this adaptation was because I was designing some adapter brackets to adapt some '94-'04 SN95 Mustang V6/GT 10½" solid rotor rear discs to this fastback to go along with the factory 4-piston K/H front discs that were on it:
1. http://img117.imageshack.us/img117/8133/65010vt3.jpg
2. http://img116.imageshack.us/img116/2711/65038ys7.jpg
3. http://img117.imageshack.us/img117/5333/65046vl9.jpg
4. http://img116.imageshack.us/img116/3176/65057yo8.jpg
5. http://img116.imageshack.us/img116/2356/65060ao0.jpg
This is an installation I did on a friend's '65 fastback back in '04. It features a 2.3L Fox brake booster and an SN95 V6 4-wheel disc MC:
1. http://img116.imageshack.us/img116/134/65053dh3.jpg
2. http://img116.imageshack.us/img116/6596/65054go8.jpg
The reason for this adaptation was because I was designing some adapter brackets to adapt some '94-'04 SN95 Mustang V6/GT 10½" solid rotor rear discs to this fastback to go along with the factory 4-piston K/H front discs that were on it:
1. http://img117.imageshack.us/img117/8133/65010vt3.jpg
2. http://img116.imageshack.us/img116/2711/65038ys7.jpg
3. http://img117.imageshack.us/img117/5333/65046vl9.jpg
4. http://img116.imageshack.us/img116/3176/65057yo8.jpg
5. http://img116.imageshack.us/img116/2356/65060ao0.jpg
ultrastang
Founding Member
Do you know for sure the rear end has 3.08 gears? or is that what someone told you it is or is shown on the gear tag?
It could be that the tag is on the wrong rear end, or the gears were changed at some point and the old 3.08 tag reattached. --just speculating here.
My '03 Mach 1 has a manual 5-speed and 3.55:1 rear gears. At 70 MPH, the engine is turning ~2,000 RPMs. This is what makes me wonder if the gears in the rear you have have been changed? --or do you have really short tires?
Here's a link from my site that has some calculators on it, plus a formula that's written out to determin RPMs. You're welcome to check it out to maybe determine what you have.
If all else fails, you can pop the rear end cover off and count the teeth on the ring gear and the teeth on the pinion. Divide the ring gear tooth count by the pinion gear tooth count to get the ratio.
http://ultrastang.com/Rearinfo.asp?Page_ID=3
Iamdiffrnt
Member
No offense, but unless you've done something to upgrade your suspension, I don't think you would want to go faster than that anyways. I know from experience (and I'm sure a few folks on here would back me up) at 120 these Mustangs are pretty scary.
mrmustangman357
Member
- Feb 11, 2007
- 763
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ultrastang, is the bolt pattern the same for putting the 2.3L booster in a 65-66? My SSBC brackets put the booster off the firewall ~1.5". Would I have to drill the firewall and bracket to get the 2.3L booster on?
ultrastang
Founding Member
The stud pattern on the booster remains the same (of course), but the location on the firewall is not the same on a '65/'66 as on a '67/'68 (mounts lower on the '67/'68 firewall).
On the '65/'66 models, the top two Fox booster studs pretty much line up with the original top two holes in the '65/'66 pedal support. The main thing to do, when mounting a Fox booster to the firewall of whatever year model you have, is to center the booster's input rod between the two holes where the original MC used to mount.
ultrastang
Founding Member
Probably has a lot to do with what type of hydroboost unit you use.
As I've mentioned, in a '67/'68 body the stock booster or a 5.0L bootser will work with a hydraulic clutch, but in a '65/'66 body it doesn't matter if you have a 2.3L or the 5.0L booster, there isn't enough room beside the booster for the hydraulic clutch MC to mount in the hole on the firewall.
An SN95 Mustang GT/Cobra hydroboost unit will fit in a '67/'68 with no problems, but the overall length of the hydro unit and MC combined is a bit too much for a '65/'66 Mustang --the fittings exit out the bottom of the MC, and the secondary side brake line tube/fitting (the one closest to the front of the car), hits the shock tower.
This is a hydroboost unit I have from a '96 Mustang GT. It was given to me by a friend who bought it for his '65 Mustang. He could not get it to fit because of the interference with the driver's side shock tower, but it fits between the firewall and shock tower with no problems on my '68, because the towers don't bulge out towards the bottom on a '67-'70 like they do on a '65/'66 (you can see the hydraulic clutch MC mounted just to the left of the hydroboost unit):
1. http://img408.imageshack.us/img408/674/96mustanggthydroboostunuw3.jpg
2. http://img406.imageshack.us/img406/8031/96mustanggthydroboostunqh7.jpg
3. http://img505.imageshack.us/img505/3718/96mustanggthydroboostunso9.jpg
I guess. Are you talking about it being stable at high speeds? Kinda floaty like?
I'm one of those people who like to push the envelope, no stranger to high speeds and traffic etc..
Only when it's safe of course. At like 2am.
I've been 110 and it wasn't that bad. But thats not what these cars are built for anyway, more for torque.
