Hey guys, instead of me having to get my rear axles redrilled from a 5x5.5 pattern to a 5x4.5 to match the MII rotors up front....can I just use some brake rotors from a late model truck with a 5x5.5 bolt pattern? or do they make aftermarket 5x5.5 MII rotors?

 

I am often surprised that many get concerned with different bolt patterns front and rear. I can't speak for others but it has been a long time since I mounted a spare and I never have had to on my 49 (on the road for 10 years and probably 60k miles including cross country). I may or may not even carry a spare. If I do I will carry a spare plus one wheel adapter. I happen to have a 72 9 " rear and a Jag IFS (chevy bolt pattern).
Am I the only one that sees it this way?

 

Oroginal MII rotors are small diameter (about 9 inches as I recall) and are probably not sufficient for use on a truck. They were barely adequate on the Mustang. You might be able to have some aftermarket kit rotors like GM or Granada (10-11 inch diameter) redrilled to 5x5.5 but the original MIIs aren't big enough. There may be some kit available that uses 5x5.5 rotors but that may be pricey...

As far as running without a spare goes...I haven't had a need for one in a number of years either but it still makes me feel better if I have one with me...

 

Most of the MII rotors I have read about have been the GM 11 inch.

 

Yeah I was just gonna run the different bolt patterns and bigger tires in the back but my dad was the one who was telling me "don't go with a different bolt pattern, its a hassle" I guess he means when dealing with rotating tires and buying new tires pluss he told me if I was gonna drive it everyday it is better to have all the tires the same.....but I don't think it would be that bad to run 2 different bolt patterns and tires

 

Classic Performance Products in Anahiem has a kit to switch to a 5 on 5.5 pattern. They are bigger rotors, calipers and a different caliper bracket. I don't remember the cost but it wasn't cheap. Works great though.
We had a customer once that had to have the stock steel wheel style with that bolt pattern.

 

If the two bolt patterns are small Ford (5x4.5) and GM (5x4.75) it's no hassle at all since most aftermarket wheels now have both patterns on the same wheel. But the 5x5.5 will always be somewhat of a hassle. There is a way to convert your nine inch to 5x4.5 that involves using left side only axles from a 73-up Torino, '77-'79 T-Bird, Cougar, LTD II, or Ranchero but I've never tried it.

 

This may be what would help?
Wheel Adapters|Lug Nuts|Wheel Spacers

 

I'm with CdnWillyG.

I have a 9 3/8 rear end with the 4.5 bolt pattern and have adaptors on the fronts to bring the pattern down from 5.5 to 4.5.

I don't rotate the tires (except from side to side) because the front and back tires are different sizes. But it is nice to only have one wheel size and know that the spare will fit on any of them.

Question: is the rear end you have with the 5.5 bolt pattern the stock rear end, or a 9" with the larger pattern? Only reason I ask is because if you are planning on a rear end swap to 9" that would solve the problem too (if you put one in with a 4.5 pattern). Or if it is a 9" maybe you could change out the axels to some with 4.5 pattern if that's possible.

 

i have it. ebc kit.bought them from fatman..it uses a billet hub, a jeep cj rotor with gm caliper.

 

Wilwood has a hub drilled for either 4.5 or 5.5 for the Mustang II. Don't see why you couldn't duplicate that with a competent machine shop.

 

What is the diameter of the Wilwood rotor? It is probably 10-11 inches which is wide enough on which to machine a 5x5.5 pattern. The stock MII rotor is only 9 inches in diameter and is not wide enough for that pattern...

 

ECI makes them: ECI Disc Brake Conversion Kits - Mustang II & Pinto

I contacted Fatman & they had me buy from ECI directly. The set-up comes with a 5x5.5 hub for the MII spindle (complete with bearings & seals), GM brake calipurs with a mount for them, and 11 5/8 rotors, which I think are actually a Dodge truck OEM rotor.

The stock steel 16" wheels don't enough clearance from the brake calipurs....the rivets in the wheels hit the calipur. I spaced the wheels out by 1/4" & they clear. Right now my chassis is just rolling stock, and I'm not planning on driving it that way....wheels with more clearance will be on my shopping list next year.

 

D4FZ1102A .. Brake Rotor-9 15/16" diameter / Fits: 1974/78 Mustang II & 1974/80 Pinto/Bobcat.

These cars came with 13" 4 lug, 4 1/4" bolt circle pattern wheels as original.

 

Hub is a separate unit. Rotor size varies. The rotor bolts to the back of the hub. I have seen 10 to 14 inches advertised.

I thought maybe you could have a good machine shop fill the existing holes and re-drill for the larger pattern.

I am taking the easy way out. With 18" wheels on the front of my truck the Wilwood brakes I want have 12" rotors and use the Wilwood hub and stock height spindle for Mustang II. With the Ride Tech control arms and air-spring it should be an improvement over stock MII hardware.

The front brakes have 4 piston calipers that are matched to the 4 piston, internal parking brake, 12" rotor Wilwood setup already in place on the rebuilt 9" rear end. This introduces a little bias to the brake system before even installing the proportioning valve.

As for the spare tire, I plan to get a Mustang space saver spare from a wrecking yard just in case. I have only had to change to the spare tire on any vehicle I ever owned probably 4 times in my life so far. I would hate to have the truck be the fifth time and not have a spare.