Any Mustang II brake upgrades that keep the 4-lug bolt pattern?

[Cobra Dude]

Really don't want to switch wheels at this point, and honestly don't need more brakes on this car -- it stops quite well. But it just looks "pansy" since the stock Mustang II discs are smaller than the rear discs (10.5").

Or does anyone sell Granada rotors that are undrilled?

Cheers,
-Neil.

[G.R.]

Originally Posted by Cobra Dude

Really don't want to switch wheels at this point, and honestly don't need more brakes on this car -- it stops quite well. But it just looks "pansy" since the stock Mustang II discs are smaller than the rear discs (10.5").

Or does anyone sell Granada rotors that are undrilled?

Cheers,
-Neil.

"pansy" just 'cuz your front discs aren't the same size as your rears? You driving a concurs show car?

Sorry couldn't help it.

I've never seen undrilled Granda or other Ford rotors...but if they are available I'm sure someone here will know where to obtain them

[Rick Parker]

I believe the 5 bolt Ford pattern (generally 4.5") may be a larger diameter circle than the 4 bolt Mustang II. Measure from center to center across the center of the wheel for the 4 bolt pattern. You DEFINATELY need more brakes on a car with the engine you have. 9" rotors from a Mustang II just don't have the margin you need. Don't kid yourself.

[Cobra Dude]

Can't remember offhand which pads I have but the combo I have works really well -- I can lock up the tires repeatedly. No, I'm sure these brakes won't cut it on the track, but for street driving they do very well.

The problem with swapping lug patterns is that I'll need to change wheels. What starts as a $40 MC swap (leaking MC) with jump to $2400 if I have to swap to 5-lug with new matching wheels, etc, etc... ugh!

Yes, the 5-bolt pattern is on a 4.5"-dia circle, the 4-lug is on a 4.25"-dia circle. That's only 0.125" apart. I tried some calcs on paper and the only orientations that I can work out have at least one hole overlapping with another. That makes me a bit uneasy. But even if I let myself do this, I'm not sure I can use the existing MII hubs with the (re-drilled) Granada rotors, as their may be issues with the bracket placement/offset, etc.

-Neil.

[Ron61]

If I were you I would really be careful about any overlapping of holes as that is going to put stress on the others and they will start to wear. I saw that happen once and it was with Pinto rotors. Fortunately when the car started to shake and wobble so bad after he had driven it for a while, he pulled the wheels and the holes were starting to wear out.

Ron

[Cobra Dude]

Originally Posted by Ron61

If I were you I would really be careful about any overlapping of holes as that is going to put stress on the others and they will start to wear...
Ron

Exactamundo! That's why I'm feeling around for other options. Once company suggested I weld up and then re-drill the holes, but I think that'll be a lot of work, and end up costing more than it should.

[Ron61]

Yes, and also if you weld the holes and re-drill, you have to be sure that you don't have the balance off any at all. I know that you are trying to save money, but there is a point that even if you just drive the car, safety becomes an issue. Remember those Pinto engines weren't nearly as heavy as your engine is. Good luck with whatever you decide to try.

Ron

[NOSMS]

If there is interest we could put togather a break kit for the 4 lug. I would use a 12.2 X 1.25 Rotor and a 4 or 6 piston caliper. Let me know.

Something like in the photos


NOSMS

[Cobra Dude]

NOSMS, what would be the (ballpark) cost of such a kit? I'd need everything to convert from a stock Mustang II setup -- rotors, calipers, brackets, and lines if different. I assume pads will be from a different source.

[A Cobra guy]

I've got the Mustang II spindles on my car with 11" Granada rotors and some GM calipers. I have hated the setup since day one. (Way too much pedal preasure)
The rotors warped last season so it is finaly upgrade time.
I believe Wilwood has a kit for the 4 bolt wheels.
I liked Wilwood because they had so much info online as to exactly what would fit my car.

I kept searching around and came across www.HotrodsUSA.com.
In my case they have exactly what I wanted. 11.75" Wilwood rotors with 4 piston calipers and no change to the wheel offset. Watch out for these kits changing your wheel position. Many kits will move the wheel out 1/2" or more to make room for bigger calipers. The kit I found has a custom zero offset changing hub that is then mated to Wilwood parts. It is a 5 bolt patern so it won't work for you.

Wilwood and Summit had a good selection of kits and rotors.

If you find a 4 bolt 11" rotor you may want new calipers too. I spoke at length with the owner at Hot Rods USA. He realy seemed to know is stuff. He said the problem of high foot presure I was having was caused largely by the single piston GM caliper. Once you go to 2,4, or 6 pistions the caliper works with alot less effort. I hope he's right because I just ordered my kit 2 days ago.

Harvey

[Cobra Dude]

Originally Posted by A Cobra guy

I've got the Mustang II spindles on my car with 11" Granada rotors and some GM calipers. I have hated the setup since day one. (Way too much pedal preasure)

Is this a comparison from stock Mustang II's, or did you have this upgrade from the first time you drove your Cobra?

AFAIK, pedal pressure is not really due to number of pistons, but somewhat to total cross-sectional area of the pistons. Pedal pressure is generally controlled by 2 things ... the pedal lever ratio (which should be 1:6 or thereabouts) and the MC bore dia. If you have discs on the rears, you'll need a bit more fluid capacity, so a 1" or thereabouts bore should be good. Smaller bores will reduce the pedal pressure. As an example, on a Mustang, when converting from power to manual brakes, the bore is generally reduced to 7/8" or even 3/4".

I believe Wilwood has a kit for the 4 bolt wheels.

I had looked on there previously, but did not find any 4-lug kits. IIRC the pdf tech docs on the MII kits I pulled up all stated "5-lug only" right at the top. Any links?

I kept searching around and came across www.HotrodsUSA.com.
In my case they have exactly what I wanted. 11.75" Wilwood rotors with 4 piston calipers and no change to the wheel offset. Watch out for these kits changing your wheel position.

Similar for this site. I had been searching extensively before I posted here. Any links and/or part numbers you have (to 4-lug options) would be much appreciated.

Offsetting my wheel a bit is not a problem, as I think the wheels could use a bit of a shift to the outside to fill up the wheel well a bit more. However, I've never checked the scrub radius on this car, so not sure if an outward offset would cause noticeable tramlining or make it more stable.

Cheers,
-Neil.

[A Cobra guy]

Neil,
I looked back at the brake sites I had been visting. No 4 lug kits. Sorry

The car came from EM with the Granada rotors & GM calipers. Over the last 8 years I have learned alot about brakes (From a base line of about 0)
The changes I've made were smaller MC sizes and pads. Feel has gotten better but is still not good. It will be a month or more but I'll let you know about the 4 piston Wilwoods when I get them on.

Harvey

[Cobra Dude]

Yep, I tried every source I could find. Also called Wilwood last week (when this forum was down) and they verified nothing with 4-lugs.

My answer right now is that the MC and PV are swapped out, some new lines put in, and the car is mostly buttoned back up. Probably better this way as the brakes work well on this car, so I should not mess with it.

-Neil.

[NOSMS]

Sorry for the delay guys. I have been out of the loop for a few days. A complete break kit with a 12.2 inch rotor and a super light 4 pistion would run just under a thousand complete.

Let me know if you are interested