9" drum to disc conversion confusion

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72swinger619

72swinger619

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Start this out simply I have a slant six 72 dart swinger that I reatored and drove a few years and now I want to go to a 318 small block so my first preperation is to swap to front disc from stock 9" drums.
I have a set of 78 aspen spindles and caliper mounts for a supposed 10" ? Rotor . My ? S are can I even use these spindles cause one site says yes and others say no, both mention differences in geometry. And I do not want to do anything less than proper. So should I just buy the whole kit for 400 that comes with a body spindles and 113/4 rotors. Or build off the b body spindles also the person I got them fronk said they will fit my stock a arms on my 72 but all other sources have stated otherwise
 
I am doing an 8 cyl swap also. I was looking into converting the brakes. I found a 9" option. Scarebird has a kit that uses Toyota Previa rotors and they include a backplate. You just have to buy Chevy celebrity calipers and pads and a Caddy hose. It is all in the setup specs. https://scarebird.com/

They will be installed pretty soon. The engine is already in, just needs to get it running.
 
The Mopar expert at Mopar Action says that while the Aspen spindles are different, they will work fine. Maybe give a little more caster or camber. Can't remember which. You will need the upper control arms from the Aspen, and the lower ball joints.(new).
 
here are some articles that might help you make a decision:

http://ecihotrodbrakes.com/dodge_plymouth_discbrake_conversions.html

http://www.moparaction.com/Tech/archive/disc-main.html

https://scarebird.com/index.php?id=30

http://www.performanceonline.com/19...AR-DISC-BRAKE-CONVERSION-KIT-SWBKS6274-19537/

http://www.classicindustries.com/mopar/parts/md7685.html

http://www.moparmusclemagazine.com/...pp_0503_swapping_a_and_b_disc_brake_spindles/


The last one is the one I used. I bought some
73/74 Charger spindles (used) for $100.
'73 and up B body lower ball joint,
'73 Charger brake hoses,
New Orielly's caliper Part # 18-4067 & 68 A1Cardone
New brakebest disc brake pads, PN MKD84
'74 Duster/Demon Masterpro ball joint P/N K781 & K783
'74 Charger rotors P/N BD60319

I also had to buy the Moog offset upper bushing so the alignment guy could bring it into specs. BIGBLOCKDART.com will tell you all you want to know about the geometry of the components (that's one of the things I was worried about). But after the swap my '69 Cuda stops on a dime and gives you change. I don't even need rear brakes.


Hope this helps,
Treblig in Texas
 
I think that scarebird kit looks quite shady it doesnt have the authenic look or strength... anyhow I have gotten some 73 dart upper control arms with the bbj, I have the b body spindles backing plates caliper mounting brackets for 10" slide style calipers and all the hardware from the donor car and have spent so far $215. Now I am trieng to figure out what the deal is with the separate hub and rotor assemblies and where to get them. I saw a diff post where ppl were saying they are off a crown vic...then machined down or somethin .
 
furyus2 said:
The Mopar expert at Mopar Action says that while the Aspen spindles are different, they will work fine. Maybe give a little more caster or camber. Can't remember which. You will need the upper control arms from the Aspen, and the lower ball joints.(new).
Click to expand...


Can you post a link to the Aspen upper control arms? Everything I have read said you have to have the 1973-76 A-body upper control arms.
 
taken from one of the articles in my previous post:


'62-'72 A-BODIES (Dart, Duster, etc.)
If your car now has 9-inch drums, the first step up would be the 10" drums used on all '65-up 8-cyl cars. We frankly wouldn't drive an A-body over 40 mph with the 9-inch drums, for reasons having nothing to do with the brakes. The small ball-joint-to- knuckle bolts, which are loaded in shear, are known to snap, usually at the most inopportune time.
The 10-inch, ‘65-72 drums are a simple R&R bolt-on. You'll need a set of the 10" drum ball joints and the aforementioned larger bolts, of course. The next step up, incrementally, would be to use the factory 4-piston Kelsey-Hayes setup. This has the advantage (or disadvantage, depending on your point of view) of keeping the weird 4-inch bolt circle hubs. If you go this route, you'll still need to swap master cylinders and add a proportioning valve as we outlined in the main text. But these brakes aren’t cheap or common anymore, and are prone to piston siezing if left unattended for any length of time.
The ultimate swap would be the unicast rotors (either size) as outlined above. To do this, you'd need everything in our parts list plus a pair of upper control arms and all four ball joints from a '73-'76 disc-brake A-car. For factory sway-bar cars, the same caveats apply to the A-bodies as we outlined in the main text for the late-sixties B-cars. But then you’ll have brakes up the yazoo. Incidentally, this is what stops the famous Mopar Action “Green Brick”.
'73-'76 A-BODIES
These cars came in two flavors, drum and disc, with the drum cars being similar to the '72-down cars (see above), with the main difference being the use of the larger ‘73-up B/E-body inner wheel bearing. The disc-equipped cars already have unicast rotors, but they used slider-type calipers. The cheapo upgrade is just swap to semi-metallic pads (slider type) and be happy. You can also use the 11.75- inch rotors and yet keep your slider setup by simply using caliper adapters from a '76-up slider- equipped B-body (these were typical on the 2-door versions such as Cordobas). You can also go all the way to the less-likely-to- stick pin-type calipers. For this, just use the adapters on our parts list, along with pin calipers from a '73-up B-body. This is handy because the '73-up calipers use the same hollow banjo-bolt hose attachment method as the original slider calipers, and you'll be able to retain your original hoses.
'73-'75 B-BODIES (Charger, Satellite, etc.)
These cars are also factory equipped with unicast rotors, but they came with pin-type calipers. A change to the larger rotors requires only a simple adapter change (to the ones shown on the parts list) and nothing more. No knuckle or caliper swap is required. The calipers on these cars mount toward the rear of the car.
'76-UP B-BODIES (Cordoba, Fury, etc.)and ‘79-up R-BODIES (St. Regis, etc.)
This group obviously already has the big rotors, etc., as these are the primary “donor" cars for our swap. For H.D. runnin', though, be sure you've got the reinforced rotors and semimetallic pads, and you're ready to rock and roll. Cars equipped with slider calipers may, if desired, be converted to the K-H pin style via an adapter swap. Use the '73-up calipers (banjo-bolt hose type,) of course.
F-BODIES and SPINOFFS (Aspen, Mirada, Diplomat, etc.)
We're referring here to all Volarés, Aspens, Miradas, Diplomats, etc. These cars use the 10.87" unicast rotors and slider calipers. As we mentioned under the later-A-body heading, you can swap up to the 11.75" rotors by simply changing to the appropriate adapters. A changeover to pin-type calipers, if desired, also requires only an adapter change, being certain to use the '73-up style pin-type calipers.
‘65-‘73 C-BODIES
Early disc-equipped incarnations of these cars used Budd 4-piston brakes, later models had K-H pin type calipers. The K-H brakes are huge (1¼" thick), in fact, they are more closely related to D-truck and B-van brakes than they are to any other Mopar passenger car. C-body disc brakes can't swap to/from any other Mopar passcars, and vice-versa. They are, literally, a class by themselves.
Along with the rest of Chrysler’s models, C-bodies went to 1- piece unicast rotors in 1973 (actually, C-bodies made the sap in late '72). This necessitated a knuckle redesign. The result is simple: for good, lowbuck brakes, with ready parts availability, you need to find a junked (or parked, if you’re quick) 1973 (or late '72) disc-equipped C-cruiser, and take everything (incl. rotors, calipers, knuckles, hoses, adapters, etc.) You won’t need the control arms, since they are identical from 1965 thru ‘73. For cars now equipped with 4-piston brakes, you will, however, need to swap the lower ball joints; but this is a blessing in disguise: The needed ball joints are way more common (read: cheaper!)
Another option for C-bodies is the Scarebird kit, see Mopar Action's December, 2009 issue. This uses stock drum knuckles, lowbuck custom adapter brackets, and a clever mix of parts-store components.


Under the "F" bodies part you'll see some Aspen info on brake rotors and calipers.

Treblig in tex
 
Thats good info thank you yes ill be using the f spindles with 10" rotors and slide calipers im trying to choose a good rotor. I have seen one piece and also separate hub and rotor assemblies are the separate style better or worse than one piece performance wise cause obviously maintenance wisevseparate seems better as I will have this car till one of us expires .... and even then id try to revive her.
 
Oklacarcollecto said:
Can you post a link to the Aspen upper control arms? Everything I have read said you have to have the 1973-76 A-body upper control arms.
Click to expand...

F body (Aspen, Volare) control arms will not fit. They are a very different piece.
You need either the 73-76 A body uppers or a set of ball joint adapters from Doctor Diff so you can use the earlier A body small ball joint uppers. No other stock UCA's will fit from any other MOPAR.

Spindles out only from the F, M, J and late B donor car for the disc brake swap.
 
72swinger619 said:
Thats good info thank you yes ill be using the f spindles with 10" rotors and slide calipers im trying to choose a good rotor. I have seen one piece and also separate hub and rotor assemblies are the separate style better or worse than one piece performance wise cause obviously maintenance wisevseparate seems better as I will have this car till one of us expires .... and even then id try to revive her.
Click to expand...

All the bbp rotors I have seen are one piece. The Kelsey Hayes 4 piston rotors were two piece.
 
Jimacuda said:
F body (Aspen, Volare) control arms will not fit. They are a very different piece.
You need either the 73-76 A body uppers or a set of ball joint adapters from Doctor Diff so you can use the earlier A body small ball joint uppers. No other stock UCA's will fit from any other MOPAR.

Spindles out only from the F, M, J and late B donor car for the disc brake swap.
Click to expand...

Thank you for confirming what I have always read.
 
You CAN use the F-body (Aspen) spindles, although they are not the ideal solution. They are taller than the A-body spindles, so angles between the upper and lower control arms won't be the same. Depending on who you ask, this is either a non issue (Steve Dulcich) or really bad (Rick Ehrenberg). In any event you'll need 73-up upper control arms with the larger ball joint, or tubular equivalents.
 
For years, it's been a common recommendation to use the '73-and-up A-Body disc-brake spindles as a starting point, and up until recently, this wasn't an issue. Now, however, the question is if you can find them, not where. Original A-Body disc brake setups are almost impossible to find in the yard as everything's getting crushed to make way for the profitable late-model wrecks. Of course, you can also use the identical '70-'74 E-Body disc spindles, but we all know there aren't any E-Bodies in junkyards.
http://www.moparmusclemagazine.com/...ing_a_and_b_disc_brake_spindles/photo_02.html

 Above, the B spindle is on the left.


So what are we to do? There's a fierce debate going on about the so-called B-Body spindle. This one spindle is actually used in all '73-and-up B-, F-, J-, M- and R-Body cars, which is a huge source for cheap disc brakes. Fifth Avenues and Diplomats are a common site in the junkyards, providing all the disc-brake spindles we could ever need. See the accompanying chart for a list of all the cars in this group.
The rumor is that these spindles cause poor geometry, binding balljoints and other problems, which will lead to the untimely demise of you and your car. Having used these spindles in various A- and B-Bodies with no problems at all, we decided to study the differences, analyze the geometry with some good software and document the honest differences. We're directly comparing the '73-'76 A-Body/'70-'74 E-Body disc spindles to the late B spindle. We'll simply call them the A or B spindle.
If you have a '63-'72 A-Body, you'll need new upper control arms from a '73-'76 A-Body, which uses the bigger K772 balljoint. Aftermarket tubular a-arms also use this bigger balljoint. Upon inspection, the first thing you'll notice is the height difference. The B spindle is about 3/8-inch taller than the A, and has a more shapely profile, making it 3 poundss lighter, helping unsprung weight. One other item of interest is the SAI, or Steering Axis Inclination. This angle is the major reason for self-centering steering on cars, more so than caster, and within limits, more is better. The A-Body spindle has a cast-in SAI of 7.5 degrees, while the B-spindle has an SAI of 8 degrees, further aiding in stability.

If you have a '63-'72 A-Body, you'll need new upper control arms from a '73-'76 A-Body, wh


To explain these differences, a little geometry background is required. There are many issues concerning front suspension, but we'll only touch on the major items that are affected by this spindle change.
Toe change can also be called "bump steer," and is the most commonly known term, and the least understood. All suspension systems exhibit some amount of bump steer, because the tie rod does not follow the same arc as the spindle in a double a-arm system. A strut suspension is much easier to work with, but that doesn't apply here. The goal is merely to minimize bump steer and to keep it within an acceptable range. Race car builders try for as little bump steer as possible, but it's basically accepted that it does not affect handling if kept below approx. 0.031-inch or 1/10 of a degree per inch of travel. Factory street cars have a much larger tolerance, usually double this amount. In basic terms, less than 1/16-inch of toe change per inch of travel is acceptable.
Also important to know is how toe-change affects the driver. In a straight line, with the nose moving up or down, both tires change the same amount, essentially canceling out the effects. Through a corner, however, the outside tire carries most of the weight, and determines most of the driver's control of the car. This means toe-change in compression is most important, as it has a bigger affect on handling. If the wheels toe-out slightly under compression, the car will turn less into the corner, called under-steer. This is typically more stable, as the driver will continue turning the wheel into the turn, which is a natural response. If the wheels toe-in substantially under compression, the car will turn more, called over-steer. The driver is forced to turn the wheel out of the turn to correct, which is not natural, causing an unstable feeling.


Read more: http://www.moparmusclemagazine.com/...isc_brake_spindles/viewall.html#ixzz2lrxkh5hl



I think this is why I had to use the Moog offset bushing. My alignment mechanic couldn't align the Cuda properly until I replaced the bushings.
Treblig
 
If I am at all dissatisfied with my spindles later will my caliper mounts and rotors fit a body spindles from 73 up. The problem was I had bought the spindles first I got the set with backing plates and caliper mounts for $95. Thought it was a good deal. And then as I read later it works but has some differences could be positive could be negative lots of mixed opinions
 
And to be safe I will get the offset bushing. Thank you everyone for helpful info I will post back when I get all remaining parts ordered
 
72 Swinger,

Be extra careful how you install the offset bushings. I really can't tell you which way they need to go. I followed the instructions but I actually had to install mine and take it to the alignment guy only to find that I had to remove the bushings and rotate them 180 degrees. It all depends on which way your spindle needs to move to get the proper alignment. I think I bought an extra set of bushings so I believe I still have the (first) new ones I removed. I can check to see if I have the extra set that I removed and sell them for a decent price if you like??

Good Luck,
Treblig
 
In the past 5 years,I've converted 3 Mopars(9") to discs.
I got the Wilwood setup from Summit,comes complete and works great.
Sam
 
Oklacarcollecto said:
Can you post a link to the Aspen upper control arms? Everything I have read said you have to have the 1973-76 A-body upper control arms.
Click to expand...

I can't find where I red that, but it wasn't Mopar Action. I must have been the other magazine. I withdraw my statement about the Apen spindles since I can't find my source.
 
Sam said:
In the past 5 years,I've converted 3 Mopars(9") to discs.
I got the Wilwood setup from Summit,comes complete and works great.
Sam
Click to expand...

I'm doing this right now. My last one was the 73 and newer disc conversion. RMS recommended the wilwood setup for function, price and weight.
 
72swinger619 said:
I think that scarebird kit looks quite shady it doesnt have the authenic look or strength...
Click to expand...
Scarebird probably isn't an option for you since you have already collected other parts, unless you decide they won't work (many report fine results w/ FMJ spindles). I wouldn't be concerned w/ Scarebird's design. It looks very strong to me, and I am a mechanical engineer. Forces on a caliper are fairly predictable since there is a built-in force limiter in the tires sliding.

I haven't heard of the 9" drum spindle failing, as one post reports. Certainly it could fail in dirt-track racing or such, but unlikely on the street as designed. I did have the outer bearing spin the race in both hubs on my 69 Dart, so that is probably the weak point. You can go overboard putting the heaviest brakes imaginable (C-body disks?), but then you lose the light-weight feature of the A-body. Ditto for sub-frame braces and such.
 
scarebird is well known in the hot rod/street rod world,,,he makes adapter kits for many vehicles that never had disc brakes,,,mostly uses off the shelf parts, some times mixes and matches,,,but it all works out if assembled properly,,,

big ball joint upper control arms are availabe thru firm feel that do not use the after market heim joint design if you perfer the hard mounted factory style,,, beats looking for 1973 and up,,,
 
Doesn't Master Power Brake offer repop upper arms, also?
 
72swinger619 said:
I think that scarebird kit looks quite shady it doesnt have the authenic look or strength... anyhow I have gotten some 73 dart upper control arms with the bbj, I have the b body spindles backing plates caliper mounting brackets for 10" slide style calipers and all the hardware from the donor car and have spent so far $215. Now I am trieng to figure out what the deal is with the separate hub and rotor assemblies and where to get them. I saw a diff post where ppl were saying they are off a crown vic...then machined down or somethin .
Click to expand...

to you the scarebird stuff might look shady and weak. (nothing looks original except original and if your going from drums to disc. it ain't original:D), but I can tell you for a fact that a 65 Plymouth satellite (big b body) with a built 440 in it can yank the wheels up and come down on the scarebird conversion just fine without breaking anything ,multiple times and stops better than the original disc conversion using mopar parts, it's easy to get NEW parts ANYWHERE, that was the main reason I went that route with my dart, I have never seen a 9 inch spindle break,the weak bolts are another story but they get replaced with stronger bolts when doing the upgrade to disc's anyways. It's all about what you want to put on your car. I'd prefer new stuff if at all possible or at least everything that I can afford to get new. your still putting on used spindles and used arms. you had used spindles and used arms originally and you just upgraded(and paid) to use "used" stuff. try getting a rotor,calipers,hoses or pads on a Sunday(or get it machines if you go the Crown Vic way, haven't heard about that one much.) at the autoparts store for that Original conversion. but you can with the scarebird conversion and be on the road as soon as you get back from the auto parts store.

I've used all sorts of setups to get my mopars into the disc brake setup and the best(also cheapest) for me using new parts is scarebirds way.
again people swear by the keep it "original syndrome" and think it's great and the only way to go. Some like it other ways and most want to keep em running without any hassles. Have fun with your disc upgrade. you'll like them better than any drum setup that's for sure no matter what way you go.
 
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