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Discussion Starter · #1 ·
Hi guys

I have a question about disc brakes, specifically a kit from tomsclassics on eBay. Before you tell me to search, I did and found this one:

http://www.fordmuscleforums.com/galaxie-pages/504919-info-discbrake-kit-4-62-500-xl.html (and another thread where the same user says the same thing)

The discs are 12” items from a 71 LTD. Does anybody know if these rotors (and associated calipers – they’re from a 78 Chev truck) will clear the inside of a 15” rim? My rims are US Racing Mag 15x7s with a bore centre that’s larger than my drums, and thus my stock 15” rims. I’d hate to buy them from the other side of the world for them not to clear my wheels… any input greatly appreciated!
 

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Discussion Starter · #3 ·
I don't suppose you know how big your hub centres are, do you? Mine are definitely "bigger" than stock. Do you think they're the same size as your ones? And are your Crown Vic rims 15s or 16s?
 

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I've been following some of these brake upgrade posts for awhile and I have a few questions. When you folks are talking about hub size / diameter, are you talking brake rotor diameter? I have a 66 Gal with aftermarket 15 X 8 rims and am concerned that my new pretty / shiny wheels won't fit due to this "hub size". Isn't the hub the part that the drum or rotor mounts to? If yes, then couldn't you just use a smaller rotor?

Don't mean to sound ignorant or stupid...but I'm ok with confused!!
 

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Discussion Starter · #6 ·
I think that 15" rim is one part of it.

This particular kit uses 12" rotors, which I believe are actually 11.75", but are frequently rounded up and referred to as 12". Those should clear the inside lip of a 15" rim by themselves. And as long as the caliper isn't enormous, that too should fit. But I wouldn't try it with a 14" rim.

The bigger issue is the hub centre. The centre bore diameter of my old stock 15" rims is as near as makes no difference 2 1/4". That fits snugly over the brake drum hub. My aftermarket rims have a larger centre hole; I haven't measured it yet (they're on the car, it's tricky!), but I reckon it's a good 1/4" wider all the way around. Which is to say the centre hole does not fit snugly on my hub - not that this really matters if the lug nuts are done up tight and proper!

The rotors on these kits usually have a larger hub diameter as they use later-model rotors, which is why they usually say "must use 15" or larger rims", or "must use disc brake rims". The kit I'm looking at has a 2 3/4" hub diameter on the rotors - ergo my stock rims wouldn't fit over them, but likely my aftermarket ones would/will. I'm just trying to be sure of this before I order a kit from the other side of the world - can't do the DIY kits because parts they require can't be bought over the counter here, so it's the full kit or nothing for me.
 

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A proper fit of the rim to the hub is essential as the weight of the car is supported by the hub, not the wheel nuts. I've experienced the total destruction the almost brand new mags where I didn't pay attention the a snug rim fit. Almost costed me my Lincoln too.
 

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Regarding your wheel size: I'm running 12.2" Wilwood brakes with 15" Tork Thrust 2 rims. They fit but just barely. I think you'll be fine.
 

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Hi guys

I have a question about disc brakes, specifically a kit from tomsclassics on eBay.
Then go onto eBay, and send Tom a message. He would be the first I would ask. Same goes for any other item being sold - ask the seller or manufacturer.

As for the hub question - there are three sizes of hubs (where the bearing is in the center of the rotor that the little grease cap fits into), which are 62.0mm, 63.4mm, and 70.3mm. The 62 was primarily 1960s small and mid-size, the 70.3 for full size early and late, and the 63.4mm for small and mid-size after about 1973. Measure yours to verify what you have before wheel or brake shopping.

Also, there are two different common mounting methods - hub-centric and lug-centric. Hub-centric has the wheel center fit the hub snugly and the hub carries the load, while the nuts just hold it on. Lug-centric has a looser center hub hole and the lugs (studs) use a different shank and nut style to center the wheel on the bolt circle. Your manual will tell you what system your car uses, as the lugs, nuts and wheels must all match that system. Finally, you need to know even if using the same wheels, as to balance them with new tires requires the shop use a hub pilot for hub-centric wheels, or stud pilot for lug-centric ones for proper centering and balancing. You wouldn't want a lug-centric wheel and tire balanced slightly off-center by it's hub, or vice-versa.

David


David

 

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Discussion Starter · #10 ·
Then go onto eBay, and send Tom a message. He would be the first I would ask.
I did - that's how I found out what components the kit uses. :)

As for the hub question - there are three sizes of hubs (where the bearing is in the center of the rotor that the little grease cap fits into), which are 62.0mm, 63.4mm, and 70.3mm. The 62 was primarily 1960s small and mid-size, the 70.3 for full size early and late, and the 63.4mm for small and mid-size after about 1973. Measure yours to verify what you have before wheel or brake shopping.
Interesting, thanks for that. Mine should be 70.3, then. But I will take a wheel off to be sure.

Also, there are two different common mounting methods - hub-centric and lug-centric. Hub-centric has the wheel center fit the hub snugly and the hub carries the load, while the nuts just hold it on. Lug-centric has a looser center hub hole and the lugs (studs) use a different shank and nut style to center the wheel on the bolt circle. Your manual will tell you what system your car uses, as the lugs, nuts and wheels must all match that system. Finally, you need to know even if using the same wheels, as to balance them with new tires requires the shop use a hub pilot for hub-centric wheels, or stud pilot for lug-centric ones for proper centering and balancing. You wouldn't want a lug-centric wheel and tire balanced slightly off-center by it's hub, or vice-versa.
Also interesting. The lug nuts I used for the mag wheels are different to those used on stock rims (as recommended by the manufacturer). The tyre shop balanced them up for me and I guess they did a good job because there's no indication that they're unbalanced on the car at any speeds I care to drive.

But good info. I really should invest in some hub inserts for the wheels, I suppose, just to be safe.
 

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Discussion Starter · #11 ·
It's taken me a while, but I've measured my wheels and they have about a 70mm centre hole. So that's good. Ordering the full kit this week (as per the link above) so once I get it and fit it all up I shall report back on how it all goes.
 

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Discussion Starter · #13 ·
$360 via FedEx. Still the cheapest full kit available. Priced up the Scarebird one and buying parts from RockAuto and all that... about $250 more expensive landed. I just don't want to bugger around with bits and pieces,
Not worth the risk...
 

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And it looks like ozoiler on AFF isn't coming back with answer too quickly either. :(

Do you have a link for the exact kit you are getting?
 

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Discussion Starter · #18 ·
Sorry the link is a different kit. He has one for a 65. Yeah, serious shipping, but with the current exchange rate it's not that horrendous. Ok, it is, but I've learned to deal with it...!
 

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Discussion Starter · #19 ·
Let me clarify on how much more cost effective this kit is than other options… my requirement is to upgrade the master cylinder to a dual bowl power assisted unit, and add discs if possible.

100% drum brake overhaul (front only), plus new power master/booster

Dearborn - $780 plus $330 shipping TOTAL $1,100
Rockauto - $390 plus $420 shipping TOTAL $810
Pick up bits through eBay Australia - $1,025 plus $250 shipping (lots of vendors) TOTAL $1,275

Disc conversion, incl power master/booster and prop valve

Scarebird (plus Rockauto for all the bits) - $515 plus $635 shipping TOTAL $1,150
Dearborn - $LOTS plus $LOTS shipping TOTAL $LOTSx2
This kit - $599 plus $360 shipping TOTAL $959

So this was presented to my wife (who almost died from shock) and I convinced her that the cheapest disc option would be by far the best use of funds, especially given that my car is a daily driver and I’m in charge of taking the kids to and from daycare (and next year it’ll be school).
 
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