11" to 12" rotor swap

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AdamR

AdamR

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While Im pricing brake parts whats needed to swap to the 12" rotors ? Calipers, brackets and rotors only ?
 
12" aftermarket, or the later model 11.75" mopar rotors?

If its 12" aftermarket, you'll need caliper brackets, calipers, rotors, and maybe also new brake lines and an adjustable proportioning valve to get the rear brake bias right. Some of those kits also recommend a new master cylinder. You'll also have to make sure you get the right kit for the type of spindle you have, some work on drum spindles, others on disk spindles.

For the later 11.75" mopar rotors you need '73-76 spindles, new rotors, and caliper brackets. The calipers are re-used, and the brake lines can be made to work if routed properly. At least on my Challenger the bias was actually improved since it was too far rear-biased to begin with, so you probably won't need an adjustable prop valve if you already have disk brakes. If you've already got 73-76 disk brake spindles, this is a piece of cake, and the braking improvement is very noticeable. Even on a big 'ol e-body. :D

And for either application you should probably replace your wheel bearings while you're at it unless you've already done this recently.
 
Yes the 11.75: pieces. What cars used these originally? I all ready have the 73 and later discs on the car.
 
11.75" rotors were available on late 1970s B - bodies, including 1977 - 78 Cordobas/Magnums, as a couple examples.
 
Did this swap not too long ago myself. You can get the bracket from any of these cars...

CHRYSLER CORDOBA(1976 - 1979)
CHRYSLER NEW YORKER(1979 - 1981)
CHRYSLER NEWPORT(1979 - 1981)
DODGE CHARGER 1976
DODGE CHARGER SPECIAL EDITION(1976 - 1978 )
DODGE CHARGER SPORT1976DODGECORONET(1975 - 1976)
DODGE CORONET BROUGHAM(1975 - 1976)
DODGE CORONET CRESTWOOD(1975 - 1976)
DODGE CORONET CUSTOM 1975
DODGE MAGNUM XE 1979
DODGE MONACO(1977 - 1978 )
DODGE MONACO BROUGHAM(1977 - 1978 )
DODGE MONACO CRESTWOOD(1977 - 1978 )
DODGE ST. REGIS(1979 - 1981)
PLYMOUTH FURY(1976 - 1978 )
PLYMOUTH FURY SALON(1977 - 1978 )
PLYMOUTH FURY SPORT(1977 - 1978 )
PLYMOUTH FURY SPORT SUBURBAN(1977 - 1978 )
PLYMOUTH FURY SUBURBAN 1977
PLYMOUTH GRAN FURY(1980 - 1981)
PLYMOUTH GRAN FURY SALON

I bought these rotors on eBay, pretty good price and quality rotors.

http://cgi.ebay.com/ebaymotors/1975...s?hash=item334c9ffd61&_trksid=p4506.m20.l1116

The brackets are on eBay all the time, usually around $100. Or you can just find one of the above cars in your local wrecking yard.

Here's a picture of everything I used, notice I needed the spindles and I used the "pin" type brackets instead of sliders.

Also, I hope those are 15" rims on your car. These won't fit with 14" rims.

IMG_3766copy.jpg
 
I've got the pin type calipers on my Valiant with the 11.75 rotors. The thing stops way better now. But, yes, you gotta have 15" wheels.....

Rev.
 
AdamR said:
No, They are 14s. Glad you mentioned that, LOL
Click to expand...

Yeah, all the car's that ran them had 15's. They actually barely clear 15's, I wouldn't be surprised if there's a 15" rim out there that would interfere with the caliper.

As you can see, they do a good job of filling up a 15" rim!

IMG_3809copy.jpg
 
72bluNblu - the list that you posted, is it to be a "complete" list of available donors? It lists the '80-'81 Gran Fury which is an M body. Would other years of M bodies work? It would be great if my '88 cop car could donate these pieces to my project...
Thanks,
C
 
That list is just what RockAuto shows under "applications" for an 11.75" rotor, not really sure if its all inclusive or not. My guess would be that there are some discrepancies. Some M bodies did have the 11.75" brakes, but I don't personally know of any applications after '81. An '88 Gran Fury uses a 10.97" disk, in fact the same one listed for a '73-'76 a body, same goes for a Chrysler 5th Ave. So, according to the part #'s at Rock Auto some of the '88 cars COULD donate rotors, but I don't think any of them had 11.75" rotors.
 
Thanks blu, I will check into this further. I do know that the rotors are huge compared to the '75 parts car (Duster)...
C
 
I got mine from a 78 cordoba at pick n pull. I think I paid about 30 bucks for the brackets.
 
Here are mine viewed through 17" Torqlites. I got the Brackets from a Cordoba enthusiast named Barry for $30 + shipping. PM me for his contact info, if needed. The rotors are the ones from iRotors on eBay, $135 shipped. Calipers just unbolted and rebolted back on, no problems.

07.jpg
 
72bluNblu said:
Yeah, all the car's that ran them had 15's. They actually barely clear 15's, I wouldn't be surprised if there's a 15" rim out there that would interfere with the caliper.

As you can see, they do a good job of filling up a 15" rim!
Click to expand...

Those look great! Much better proportions than on mine.
 
jimmyray said:
Those look great! Much better proportions than on mine.
Click to expand...

That's what I was thinking. That looks like a lot more than an extra 1" around the rotor. My calipers nearly touch the inside of the rim!

Maybe I'm totally wrong, but did you measure the rotors? Not all Cordoba's had 11.75" rotors, and it doesn't look like iRotor gives the dimensions on theirs (they also list for up to '83 on application, no 11.75's after '79-80 on the Cordoba).

http://cgi.ebay.com/ebaymotors/Chrysler-Cordoba-75-83-Drill-Slot-Front-Brake-Rotors_W0QQitemZ250454707992QQcmdZViewItemQQptZMotors_Car_Truck_Parts_Accessories?hash=item3a50438f18&_trksid=p4506.c0.m245&_trkparms=65%3A12|39%3A1|72%3A1171

Maybe its just an optical illusion from the distance/angle of the camera?
 
72bluNblu said:
That's what I was thinking. That looks like a lot more than an extra 1" around the rotor. My calipers nearly touch the inside of the rim!

Maybe I'm totally wrong, but did you measure the rotors? Not all Cordoba's had 11.75" rotors, and it doesn't look like iRotor gives the dimensions on theirs (they also list for up to '83 on application, no 11.75's after '79-80 on the Cordoba).

.....


Maybe its just an optical illusion from the distance/angle of the camera?
Click to expand...


He's got 17" rims and you have 15" rims. So he has more space in there.
 
autoxcuda said:
He's got 17" rims and you have 15" rims. So he has more space in there.
Click to expand...

True, but that should still only be an extra inch of space around the whole rotor. Just looks like more than that to me. :scratch:

Could just be the picture though, maybe a smaller lip on the rims too? I dunno, maybe I'm nuts. :dontknow:

I do know of at least one person that ended up with 10.87"caliper brackets that thought they were getting 11.75's based on the year/make/model of the donor car though, and we all know how honest everyone is on eBay #-o

I'm sure I'm wrong but I thought I'd mention it anyway, if it were my car and I was comparing those pictures I'd probably have to head out to the garage with a tape measure just to make sure. Maybe that's just me.
 
Great thread! just to clarify.to use the 11" rotors,you just need the caliper brackets & use the 73-6 a body disc spindles? The 11" rotors fit on the a body spindles w/o issue?
 
Sedanman said:
Great thread! just to clarify.to use the 11" rotors,you just need the caliper brackets & use the 73-6 a body disc spindles? The 11" rotors fit on the a body spindles w/o issue?
Click to expand...

Yep. I bought my 68 Dart with the LBP 73-76 A-body 10.75 disks.

All I did was get the 11.75 caliper adapters that fit my existing caliper type (pin or slider) AND get some good junkyard 11.75 rotors (they're like under $60 new). AND run 15" rims. That's it.

Don't need to bleed the brakes and you use the same old brake pads. Two bolts to get the the caliper off. Two bolts to get the caliper adapter off. And one bolt and a cotter pin to get the rotor off.

The 11.75 rotor take the same bearings as your existing 10.75 rotors.
 
72bluNblu said:
I do know of at least one person that ended up with 10.87"caliper brackets that thought they were getting 11.75's based on the year/make/model of the donor car though, and we all know how honest everyone is on eBay .
Click to expand...

I had the same concern about sizing. I e-mailed iRotors ahead of time for the specs, and they sent me the below, which was exactly what I received, except for the weight, which was off by +20 lbs.

FWIW,
my A-body 10.7" rotors weighed 22 lbs
the Cordoba 11.75" rotors weighed 27 lbs

08.jpg


24.jpg
 
jimmyray said:
I had the same concern about sizing. I e-mailed iRotors ahead of time for the specs, and they sent me the below, which was exactly what I received, except for the weight, which was off by +20 lbs.=P~

FWIW,
my A-body 10.7" rotors weighed 22 lbs
the Cordoba 11.75" rotors weighed 27 lbs
Click to expand...

Well there you go :-D! I think part of it is really just the difference in the pictures, a little angle and the distance of the camera make a big difference.

Cool info on the weights as well, I knew the 11.75's were probably heavier but I didn't know how close they were. Obviously different manufacturers probably have different weights, but I'd suspect they'd be in the ballpark.
 
Is there some were besides ebay i could find these parts?
I would like the beefed up HD adapter brackets.
 
I'm striking out on Ebay. Plus I have concerns the 11.75" package might not clear my 15x7 draglites. I hear clearance on aftermarket wheels is hit and miss.
 
Please school me on puttin the big disc brakes on a 67 barracuda with drums now. I don’t want to spend 1000 plus on the upgrade if I don’t gotta. Thanks
 
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