Another brake swap question

[JGC403]

Disc Brake Swap, 11 3/4" rotors and LBP wheels.

I know it’s been covered before on here I just want to make sure that all of what I found is correct. I have been trying to figure out what all is needed to convert my 1968 Barracuda to disc brakes with the larger bolt pattern. From what I have read I need the following parts from a 1973-1976 A body:

-Upper and lower control arms
-Spindles
-Calipers, larger piston bore from 1976 A-body or 1976-1980 F-body
-Rotors 11 3/4" from 1976-78 B-body or 1979-81 R-body
-Caliper adapter bracket from 1976-78 B-body or 1979-81 R-body
-Master cylinder
-Valving

I have read that you might loose some of your turning radius if you use the stock drum brake lower control arms. So is it easier to use the 1973-76 A-body lower control arms? I have also read that stock sway bar will interfere with the calipers.

Am I missing anything? Just want to make sure I have the right parts list before I go looking around the Junk Yards. Thanks.

 

[71DartGuy]

I got everything from a 73 dart- UCA's, spindles, calipers, brackets, splash shields. You dont need the LCA's. My drums ones worked fine- the Lower ball joints are the same size drum to disk. The uppers are the larger ones. I cant help you with the F body stuff- never did any research on it

 

[green1]

I bought my kit from Masterpower, they included lower ball joints, I can't remember, but it seems the bolts and spacing were different. You need the backing plate/splash shield.

 

[JGC403]

I added the splash shields to my list.

Has anyone used the larger 11 3/4" rotors from an R-body and the calipers with the larger piston from an F-body?

 

[72bluNblu]

I wouldn't bother with the splash shields. They're almost useless for their intended purpose, but do trap dust and heat close to the rotor.

I have 11 3/4" disks on my Challenger, they were intended for a Cordoba. Drilled and slotted, off of eBay. They work just fine!

I re-used the calipers that were off of my Challenger, so, they're the slightly smaller diameter. The larger diameter pistons may give you a little more braking force, but they also will use more fluid, so it will change your front/rear bias, and the pedal location. This will also depend on the master cylinder used. In addition to the proper proportioning valve for a disk/drum set up, you may want to think about an adjustable proportioning valve. Might not be necessary, but it would let you adjust your front/rear bias if you need to. With the 11 3/4" disks and 11" rear drums on my Challenger the bias is pretty good, but its also a heavier car.

The lower ball joint may be different. I know it is if you had 9" drums, but I'm not sure if it is for 10" drum set ups. You're already in there, wouldn't hurt to change the ball joint while you're at it.

Sway bar interference may come into play with the larger rotors, but it will be the calipers that hit. One thing you may consider doing is swapping the calipers to the rear of the rotor, you can do this by swapping the entire spindle, caliper bracket and caliper side to side. You might need different brake lines to pull this off though.

And finally, the larger rotors will not fit 14" rims. So, if you don't have 15" rims already, you'll need those too. The 11 3/4" rotors barely fit into 15" rims.

 

[dodgedifferent2]

On my 67 dart i am going to use the Mopar Action green brick setup.

11 3/4 rotor from 1976-78 B-body
73 + upper control arm
73 + drum brake spindle
Adapter plate from mancini racing (ar engineering) to mount the 92-02 viper caliper
And switching the K member to the spool type engine mounts.

I will use the existing lower control arm because they are the same as 73 +. The only difference is the sway bar tabs. 73+ used a shorter sway bar.

I have not decided on the master cylinder and booster yet.

 

[JGC403]

Thanks for the input. I will probably need a proportining valve anyways, because I would like to do disc in the back as well.

Not sure what size drums are on it now, I will have to go and measure them. So that will determine if I need to get the lower control arm or not.

The sway bar that is on it now is small. So I'll be getting a bigger one. With an aftermarket sway bar could it still come in contact with the caliper?


Is there an advantage to the Viper calipers?

And why are you changing the K-frame?

I'll need to find a master cylinder that can handle front and rear discs.

 

[dodgedifferent2]

well the 73+ has a narrow mounting position near the shock mount
the 72 down sway bar is mounted out wide near the ball joint. This is the sway bar that causes some problems with caliper so i have been told.

The advantage is 4 piston clamping pressure and a bit lighter in weight.

Changing the k frame to gain the spool mounts. The 67 engine mounts are expensive and the spool mounts are stronger.

I am also planning on putting the jeep cherokee rear disc brakes to the 8 3/4. With my own mounting plates.

 

[JGC403]

well the 73+ has a narrow mounting position near the shock mount
the 72 down sway bar is mounted out wide near the ball joint. This is the sway bar that causes some problems with caliper so i have been told.

The advantage is 4 piston clamping pressure and a bit lighter in weight.

Changing the k frame to gain the spool mounts. The 67 engine mounts are expensive and the spool mounts are stronger.

I am also planning on putting the jeep cherokee rear disc brakes to the 8 3/4. With my own mounting plates.

Reducing weight is what I am trying to do on this build, especially unsprung weight. So lighter calipers would be a bonus. How much are the Viper calipers though?

Since the spool mounts are stronger I will probably do the samething as you then and switch the K-frame.

Are you going to sell those backing plates? I was considering the cherokee brake swap for the back after seeing a couple thread about them.

 

[72bluNblu]

The sway bar that is on it now is small. So I'll be getting a bigger one. With an aftermarket sway bar could it still come in contact with the caliper?

Yes. The problem isn't so much the size of the bar, its the location. The pre-73 sway bars mount farther out, and don't run through the K member. A larger aftermarket, early style sway bar will likely be even worse in regard to caliper clearance.

Is there an advantage to the Viper calipers?

Lighter, possibly more clamping power. More things to go wrong though with multiple pistons. Big thing here is that the adapter to mount them uses a drum brake spindle, so no spindle swap. I thought these used a different rotor though (same size, but not actually a Cordoba rotor). I could be wrong. :dontknow:

And why are you changing the K-frame?

He already mentioned it, but the spool type engine mounts are better. The big difference though is the sway bar, the later K frame allows the sway bar to pass through it, and therefore the sway bar is shorter and mounted in a better, more out of the way location. You can't run a '73 up sway bar without a '73 up K frame (or '73 up LCA's).

 

[dodgedifferent2]

How much are the Viper calipers though?

Are you going to sell those backing plates? I was considering the cherokee brake swap for the back after seeing a couple thread about them.

I found my viper calipers on Ebay, but there are a few viper specific wrecking yards out there. I cant remember what i paid for mine. i think it was $150

When i figure out my setup i could sell the backing plates. I did not like the spacer idea thats why i figure to build my own backing plate. http://www.forabodiesonly.com/mopar/showthread.php?t=105241


I am not sure what shape the original cherokee backing plates will be in after i do my thinking.

 

[JGC403]

Sway bar interference may come into play with the larger rotors, but it will be the calipers that hit. One thing you may consider doing is swapping the calipers to the rear of the rotor, you can do this by swapping the entire spindle, caliper bracket and caliper side to side. You might need different brake lines to pull this off though.

Won't the steering arm on the spindle go from the back to the front when you swap the spindles around?

 

[72bluNblu]

Won't the steering arm on the spindle go from the back to the front when you swap the spindles around?

Nope. Steering arm is part of the lower ball joint, not the spindle. And the the lower ball joint mounts are symmetrical, so the only thing that changes is the location of the caliper. These are magnumforce drop spindles (not stock), but you get the idea.

 

[JGC403]

Ok I see how it works now.

Those tubular upper control arms that you have in the picture, were they lighter than the stock ones?

 

[JGC403]

An updated lists:
Viper caliper would be cool, but I think I will stick with the stock sliding calipers for now. I should have plenty of braking power with the 11.75" rotors for this A-body.

Will I need the lower control arms because of the different sway bar mounting on the later K-frame?

Most parts from a 1973-76 A-body.

-K-frame (spool type)
-Upper control arm (probably tubular)
-Lower control arms (boxed)
-Ball joints
-Bearings
-Spindles (probably drop ones)
-Dust shield
-Calipers, larger piston bore from 1976 A-body or 1976-1980 F-body
-Rotors 11 3/4" from 1976-78 B-body or 1979-81 R-body
-Caliper adapter bracket from 1976-78 B-body or 1979-81 R-body
-Master cylinder
-Valving
-Proportioning valve

I'll be swapping the calipers to the rear of the rotors, to make sure there is no sway bar interference and because I think they look better in that position.

 

[mtandrews]

M body spindle and caliper w/ hoses, St. Regis 11.75 rotors, stock booster with 73 A-Body MC

 

[JGC403]

But to swap in a Big Block I need to keep the '67-72 K-frame.

Why doesn't Schumacher make Big Block conversion motor mounts for the '73 and up K-frames?

 

[dgc333]

well the 73+ has a narrow mounting position near the shock mount
the 72 down sway bar is mounted out wide near the ball joint. This is the sway bar that causes some problems with caliper so i have been told.

The advantage is 4 piston clamping pressure and a bit lighter in weight.

Changing the k frame to gain the spool mounts. The 67 engine mounts are expensive and the spool mounts are stronger.

I am also planning on putting the jeep cherokee rear disc brakes to the 8 3/4. With my own mounting plates.

If you are using the 72 down k- member you can make sway bar clearance by swapping the left side spindle and caliper to the right and right to the left. This will position the caliper behind the ball joint just like a F body.